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Turbocharging for economy #1085048 09/29/11 11:41 AM 09/29/11 11:41 AM
Joined: Aug 2003 Posts: 4,481 Mesa, AZ P Pat_Whalen OP super gas
Pat_Whalen OP super gas P Joined: Aug 2003 Posts: 4,481 Mesa, AZ	I know that a turbocharged engine has the potential to be more fuel efficient than an equally spec'ed N/A engine. Is that something that is easily done? I've got a late 70's low compression 440 in my 80 Ramcharger (3.23 gears) and was wondering if there was any feasibility to adding a turbo (without any internal engine mods) and seeing an increase in highway economy. Point me in the right direction if you will

Re: Turbocharging for economy [Re: Pat_Whalen] #1085049 09/29/11 12:06 PM 09/29/11 12:06 PM
Joined: Jan 2003 Posts: 24,562 Brookeville, Md Mr.Yuck Not enough dumb comments...yet
Mr.Yuck Not enough dumb comments...yet Joined: Jan 2003 Posts: 24,562 Brookeville, Md	any economical gain will be thwarted by the cost of the set-up. Not sure how it would gain MPG because when the engine is not under load there will be no boost. I think this is why new cars use turbos. Because they can make good H/P with small cubic inches, but when you step into it and the boost hits the H/P goes up. Under normal driving conditions the engine maintains it's good mpg. I'm guessing if you drove around like a mad man and stayed in the boost your mpg would suffer. But I'm probably wrong about all that. [IMG]http://i66.tinypic.com/pui5j.jpg[/IMG] Coming soon!!!!

Re: Turbocharging for economy [Re: Pat_Whalen] #1085050 09/29/11 12:23 PM 09/29/11 12:23 PM
Joined: Dec 2006 Posts: 3,533 Indiana F Fury Fan master
Fury Fan master F Joined: Dec 2006 Posts: 3,533 Indiana	Key point - equally-spec'd (which I will take to mean same max torque and HP). To gain MPG I think you'd need to go to a smalelr engine boosted to the same overall output, so that when not in boost you benefit from the smaller engine. There might be some engine combinations that might become more efficient at certain RPM when boosted, but as a rule I'd say boosting an engine will drop MPG.

Re: Turbocharging for economy [Re: Pat_Whalen] #1085051 09/29/11 02:58 PM 09/29/11 02:58 PM
Joined: Jan 2003 Posts: 28,067 Irving, TX feets Senior Management
feets Senior Management Joined: Jan 2003 Posts: 28,067 Irving, TX	The turbocharged engine will get more energy out of the fuel it burns when compared to a similar output n/a engine. The turbo engine has a more fuel efficient cam profile in most cases. However, dropping a turbo on an existing engine will not return better mileage on the street. We are brothers and sisters doing time on the planet for better or worse. I'll take the better, if you don't mind. - Stu Harmon

Re: Turbocharging for economy [Re: feets] #1085052 09/29/11 06:25 PM 09/29/11 06:25 PM
Joined: Jan 2005 Posts: 2,540 Milwaukee WI T TRENDZ master
TRENDZ master T Joined: Jan 2005 Posts: 2,540 Milwaukee WI	I gotta dis-agree with you, Feets. You will never see bsfc numbers in the .4s with any turbo engine(with the exception of direct injected engines). It's not all that uncommon to see .45 in a well thought out n/a engine. The myth of economy with a turbo engine comes from, as previously stated, a smaller engine that is capable of making the hp of a larger engine. If you were to use that smaller engine in boost all the time though, you would be no further ahead in economy. It's the time out of boost with a smaller engine that you see your gains in economy. "use it 'till it breaks, replace as needed"

Re: Turbocharging for economy [Re: TRENDZ] #1085053 09/29/11 10:55 PM 09/29/11 10:55 PM
Joined: Aug 2003 Posts: 4,481 Mesa, AZ P Pat_Whalen OP super gas
Pat_Whalen OP super gas P Joined: Aug 2003 Posts: 4,481 Mesa, AZ	I can only guess that what is to follow is a direct result of not knowing much about turbos: My understanding was that because a turbocharged engine will produce an equal amount of power more efficiently than a similiar N/A engine that there could potentially be a higher efficiency at highway speeds. For example, if it takes 100HP to keep my truck moving at 65MPH on the freeway (~2100rpm), the turbo'd engine will be able to produce that 100HP more efficiently using less fuel. Is this inaccurate?

Re: Turbocharging for economy [Re: Pat_Whalen] #1085054 09/29/11 11:04 PM 09/29/11 11:04 PM
Joined: Feb 2003 Posts: 21,318 Manitoba, Canada DaytonaTurbo Too Many Posts
DaytonaTurbo Too Many Posts Joined: Feb 2003 Posts: 21,318 Manitoba, Canada	Quote: I can only guess that what is to follow is a direct result of not knowing much about turbos: My understanding was that because a turbocharged engine will produce an equal amount of power more efficiently than a similiar N/A engine that there could potentially be a higher efficiency at highway speeds. For example, if it takes 100HP to keep my truck moving at 65MPH on the freeway (~2100rpm), the turbo'd engine will be able to produce that 100HP more efficiently using less fuel. Is this inaccurate? On the highway at a steady speed, you will have no boost. Your engine will be under vacuum just like a n/a engine. The turbo engine sees no benefits from the turbo itself in this scenario because you are just taking the turbo along for the ride. The only difference is the turbo engine may have a milder cam, resulting in better economy during normal driving. However the turbo engine may have a lower compression ratio, offsetting or partially offsetting the gains of the milder cam.

Re: Turbocharging for economy [Re: TRENDZ] #1085055 09/30/11 12:03 PM 09/30/11 12:03 PM
Joined: Nov 2006 Posts: 2,255 IL furious70 top fuel
furious70 top fuel Joined: Nov 2006 Posts: 2,255 IL	Quote: I gotta dis-agree with you, Feets. You will never see bsfc numbers in the .4s with any turbo engine(with the exception of direct injected engines). It's not all that uncommon to see .45 in a well thought out n/a engine. The myth of economy with a turbo engine comes from, as previously stated, a smaller engine that is capable of making the hp of a larger engine. If you were to use that smaller engine in boost all the time though, you would be no further ahead in economy. It's the time out of boost with a smaller engine that you see your gains in economy. Herb's old book shows bsfc in that range with water injection and turbos. I believe Booster is seeing that kind of results with his TT340, but he's spent 20yrs engineering that systems to be as good as any OEM setup for the street. Would have to talk to Tom Vaught on tmf, but I wouldn't be surprised if Ford's Ecoboost systems are among the most efficient engines out there right now (they are direct injected though) To the OP's concerns, if you wanted better mpg you'd probably replace that 440 with a boosted 318. OR, if you wanted to make 600hp with your 440 and have good street manners, you could boost it rather than put big heads and cam in it. Corky's book explains it well saying 'at best the turbo system is a mild restriction in the system under light load and will cause a small loss in efficiency'. The 'gain' in mpg is not over the existing engine but in any upgraded NA engine that would compete with it for equal power. Last edited by furious70; 09/30/11 12:05 PM. 70 Sport Fury 68 Charger 69 Coronet 72 RR

Re: Turbocharging for economy [Re: Pat_Whalen] #1085056 09/30/11 05:52 PM 09/30/11 05:52 PM
Joined: Nov 2003 Posts: 1,969 Chandler, AZ Duner top fuel
Duner top fuel Joined: Nov 2003 Posts: 1,969 Chandler, AZ	I got better mileage on the street just from adding a turbo on my 2000 4.7 Dakota. But I will be the first to admit it is because I drove it different. The turbo would spool up and come on like a light switch with any more than 1/4 throttle applied... so I pretty much drove it at 1/4 or less unless I was going WOT. Without the turbo, I would catch myself leaning into the throttle at 1/2 or 3/4 all the time - which is where my mileage went. I don't doubt that the turbo aided efficiency even when it wasn't at WOT - but I could buy a whole bunch of fuel for what the system costs.

Re: Turbocharging for economy [Re: Duner] #1085057 09/30/11 11:05 PM 09/30/11 11:05 PM
Joined: Jan 2007 Posts: 7,664 IN A ahy master
ahy master A Joined: Jan 2007 Posts: 7,664 IN	Turbo BSFC numbers on a dyno may often be better than NA... except that is at high load. At real "road HP" - off boost - the lower compression ratio on a turbo hurts. Agree as several have posted, a smaller engine with turbo may do better in real world driving compared to a larger NA engine. Comparing same sized engines, the turbo would likley be worse than NA though.

Re: Turbocharging for economy [Re: Duner] #1085058 09/30/11 11:42 PM 09/30/11 11:42 PM
Joined: Jan 2005 Posts: 12,419 Kalispell Mt. H HotRodDave I Live Here
HotRodDave I Live Here H Joined: Jan 2005 Posts: 12,419 Kalispell Mt.	Quote: I got better mileage on the street just from adding a turbo on my 2000 4.7 Dakota. But I will be the first to admit it is because I drove it different. The turbo would spool up and come on like a light switch with any more than 1/4 throttle applied... so I pretty much drove it at 1/4 or less unless I was going WOT. Without the turbo, I would catch myself leaning into the throttle at 1/2 or 3/4 all the time - which is where my mileage went. I don't doubt that the turbo aided efficiency even when it wasn't at WOT - but I could buy a whole bunch of fuel for what the system costs. Since the engine is not under boost at cruise the turbo has no ability to improve mpg, however the factory programming is terrible for MPG and since your computer was reprogrammed that alone is where your mpg improvement probably came from. I am not causing global warming, I am just trying to hold off a impending Ice Age!

Re: Turbocharging for economy [Re: HotRodDave] #1085059 10/01/11 09:26 AM 10/01/11 09:26 AM
Joined: Jun 2008 Posts: 10,847 Oakdale CT gdonovan I Live Here
gdonovan I Live Here Joined: Jun 2008 Posts: 10,847 Oakdale CT	Quote: Since the engine is not under boost at cruise If I may? This is a falsehood. As someone who has spent a LOT of time boosting engines I see boost with the cruise control on all the time. Hills gentlemen, hills. Some cars like the SRT-4 see boost off idle, ridiculous. You can size a turbo so large that you almost never see boost at cruise but that does take some of the fun out the package. I agree with the poster who already pointed out that the mpg gains come from the ability to run a smaller motor at cruise and a "larger one" as needed under boost. An example I would use would be the 2.2 engine at 0 boost would be using as much air as a 135 CID engine. At 14 psi indicated boost (twice atmosphere) using as much air as a 270 CID engine and so on. Simplistic, but you get the general idea.

Re: Turbocharging for economy [Re: gdonovan] #1085060 10/01/11 10:20 AM 10/01/11 10:20 AM
Joined: Jan 2003 Posts: 24,562 Brookeville, Md Mr.Yuck Not enough dumb comments...yet
Mr.Yuck Not enough dumb comments...yet Joined: Jan 2003 Posts: 24,562 Brookeville, Md	Quote: Quote: Since the engine is not under boost at cruise If I may? This is a falsehood. As someone who has spent a LOT of time boosting engines I see boost with the cruise control on all the time. Hills gentlemen, hills. Some cars like the SRT-4 see boost off idle, ridiculous. You can size a turbo so large that you almost never see boost at cruise but that does take some of the fun out the package. I agree with the poster who already pointed out that the mpg gains come from the ability to run a smaller motor at cruise and a "larger one" as needed under boost. An example I would use would be the 2.2 engine at 0 boost would be using as much air as a 135 CID engine. At 14 psi indicated boost (twice atmosphere) using as much air as a 270 CID engine and so on. Simplistic, but you get the general idea. a turbo 4 banger might pull boost at cruise but a BB will not. I had many many highway and cruise miles on my old S/C'd 440. It never pushed any boost at speed. With vacuum readings of 20+ how can it? It would go into boost until vacuum was near 0.

Re: Turbocharging for economy [Re: Mr.Yuck] #1085061 10/01/11 10:25 AM 10/01/11 10:25 AM
Joined: Jun 2008 Posts: 10,847 Oakdale CT gdonovan I Live Here
gdonovan I Live Here Joined: Jun 2008 Posts: 10,847 Oakdale CT	Quote: a turbo 4 banger might pull boost at cruise but a BB will not. I had many many highway and cruise miles on my old S/C'd 440. It never pushed any boost at speed. With vacuum readings of 20+ how can it? It would go into boost until vacuum was near 0. Will all depend on how the turbos are sized. We are talking turbos, NOT superchargers as you have indicated in your post.

Re: Turbocharging for economy [Re: gdonovan] #1085062 10/01/11 11:34 PM 10/01/11 11:34 PM
Joined: Nov 2006 Posts: 2,255 IL furious70 top fuel
furious70 top fuel Joined: Nov 2006 Posts: 2,255 IL	IIRC it took a pretty good hill for my old 90 Daytona with a 2.5 in the tiny mistu turbo to go into boost, if that car didn't do it often I don't know what one would? I know my 86 Shelby Charger took more to do it. Haven't been on any 'big' hills yet with the Fury, but so far it's never in boost unless I put my foot into it more than necessary, and it's got pretty tiny turbos on it. 70 Sport Fury 68 Charger 69 Coronet 72 RR

Re: Turbocharging for economy [Re: furious70] #1085063 10/02/11 08:29 AM 10/02/11 08:29 AM
Joined: Jun 2008 Posts: 10,847 Oakdale CT gdonovan I Live Here
gdonovan I Live Here Joined: Jun 2008 Posts: 10,847 Oakdale CT	Quote: IIRC it took a pretty good hill for my old 90 Daytona with a 2.5 in the tiny mistu turbo to go into boost, if that car didn't do it often I don't know what one would? My 89 Shelby Daytona with a 2.2 would do it all the time with the stock Garrett.

Re: Turbocharging for economy [Re: gdonovan] #1085064 10/02/11 09:49 PM 10/02/11 09:49 PM
Joined: Jan 2005 Posts: 2,540 Milwaukee WI T TRENDZ master
TRENDZ master T Joined: Jan 2005 Posts: 2,540 Milwaukee WI	What year was the switch from throttle plate before the turbo to after the turbo? This could be the difference in your experiences... "use it 'till it breaks, replace as needed"

Re: Turbocharging for economy [Re: TRENDZ] #1085065 10/03/11 06:22 AM 10/03/11 06:22 AM
Joined: Jun 2008 Posts: 10,847 Oakdale CT gdonovan I Live Here
gdonovan I Live Here Joined: Jun 2008 Posts: 10,847 Oakdale CT	Quote: What year was the switch from throttle plate before the turbo to after the turbo? This could be the difference in your experiences... 89 and 90 have the same intake and throttle body. I have seen this in other turbo applications including the old log intake cars.

Re: Turbocharging for economy [Re: gdonovan] #1085066 10/03/11 09:26 AM 10/03/11 09:26 AM
Joined: Jan 2003 Posts: 24,562 Brookeville, Md Mr.Yuck Not enough dumb comments...yet
Mr.Yuck Not enough dumb comments...yet Joined: Jan 2003 Posts: 24,562 Brookeville, Md	Quote: Quote: a turbo 4 banger might pull boost at cruise but a BB will not. I had many many highway and cruise miles on my old S/C'd 440. It never pushed any boost at speed. With vacuum readings of 20+ how can it? It would go into boost until vacuum was near 0. Will all depend on how the turbos are sized. We are talking turbos, NOT superchargers as you have indicated in your post. boost is boost doesn't matter how it's made. Unless you don't have a bypass or POV it's not going to push air until the engine is under load. A 440 w/ 3.23 gears is not going to create load at 75mph on the highway.

Re: Turbocharging for economy [Re: Mr.Yuck] #1085067 10/03/11 05:14 PM 10/03/11 05:14 PM
Joined: Jun 2008 Posts: 10,847 Oakdale CT gdonovan I Live Here
gdonovan I Live Here Joined: Jun 2008 Posts: 10,847 Oakdale CT	Quote: boost is boost doesn't matter how it's made. If I may, you are showing an appalling lack of knowledge regarding turbochargers. Not all boost is created equal, I'm sure several members of the board would be more than happy to point that out. Superchargers are directly run of the crankshaft, turbochargers are run off exhaust flow. I can hold the throttle at one point and go up a hill and the car would be very happy to go from vacuum to boost just due to the increased load on the engine. Turbos are NOT superchargers aside from the fact they make positive pressure. I have owned over a dozen turbocharged vehicles and have worked on thousands of customers cars. Turbo and supercharged.

Re: Turbocharging for economy [Re: gdonovan] #1085068 10/03/11 06:39 PM 10/03/11 06:39 PM
Joined: Jan 2003 Posts: 24,562 Brookeville, Md Mr.Yuck Not enough dumb comments...yet
Mr.Yuck Not enough dumb comments...yet Joined: Jan 2003 Posts: 24,562 Brookeville, Md	Quote: Quote: boost is boost doesn't matter how it's made. If I may, you are showing an appalling lack of knowledge regarding turbochargers. Not all boost is created equal, I'm sure several members of the board would be more than happy to point that out. Superchargers are directly run of the crankshaft, turbochargers are run off exhaust flow. I can hold the throttle at one point and go up a hill and the car would be very happy to go from vacuum to boost just due to the increased load on the engine. Turbos are NOT superchargers aside from the fact they make positive pressure. I have owned over a dozen turbocharged vehicles and have worked on thousands of customers cars. Turbo and supercharged. A s/c will also go into boost up a hill or if you need to mash it to pass. Are turbos not regualted by engine vacuum? They do not always make boost at all rpms. You are right I'm pretty much a novice at this but I'll stand by what I said a 440 turbo'd car is not going to create any boost at highway speeds under zero load...it will not have any effect on the mpg of the vehicle in question. If anything it will make his milage worse because when the boost starts it WILL dump more gas, or it better. And once you go boost it's hard to keep your foot off the go pedal.

Re: Turbocharging for economy [Re: Mr.Yuck] #1085069 10/03/11 07:43 PM 10/03/11 07:43 PM
Joined: Jun 2008 Posts: 10,847 Oakdale CT gdonovan I Live Here
gdonovan I Live Here Joined: Jun 2008 Posts: 10,847 Oakdale CT	Quote: You are right I'm pretty much a novice at this but I'll stand by what I said a 440 turbo'd car is not going to create any boost at highway speeds under zero load.. At highway speeds you are going to be under some sort of load short of coasting down a hill. zero load and highway speeds are mutually exclusive as it takes "x" amount of power to run at speed mph due to mass and frontal area. My Reliant takes 50 more hp to cut through the air at 140 mph compared to a Charger just due to frontal area alone. As I already pointed out, some cars will make boost just off idle and gave an example. SRT-4's are notorious for it. Most turbochargers are regulated by boost pressure- Most waste gates don't open till target boost levels are/almost achieved. Minimum boost on my Daytona was 12 psi, maximum was 30 (all of it setting)

Re: Turbocharging for economy [Re: gdonovan] #1085070 10/04/11 12:05 PM 10/04/11 12:05 PM
Joined: Nov 2006 Posts: 2,255 IL furious70 top fuel
furious70 top fuel Joined: Nov 2006 Posts: 2,255 IL	trying to tie SC and turbo behavior together is a faulty exercise. Without delving into anything technical to explain it, it can be visibly seen in this example: Pace a loaded semi up a big hill on the freeway and listen. He won't downshift, maybe won't even move his accelerator pedal or pick up the rpms but as his engine works against the load of the hill and the exhaust temps rise, you'll hear his turbo spool more and more. A SC is never going to do that. My point is that my experience with my turbos cars (only 1/2 dozen old turbo dodges and now my TT383 in the fury) is that it takes a big hill in order to go into boost. It is pretty easy to get my Fury from cruise @ 20" vac to 'preboost' @10" vac and start to hear the turbos spool up, but I don't go into actual boost unless jab the throttle. 70 Sport Fury 68 Charger 69 Coronet 72 RR

Re: Turbocharging for economy [Re: furious70] #1085071 10/04/11 01:42 PM 10/04/11 01:42 PM
Joined: Jan 2003 Posts: 24,562 Brookeville, Md Mr.Yuck Not enough dumb comments...yet
Mr.Yuck Not enough dumb comments...yet Joined: Jan 2003 Posts: 24,562 Brookeville, Md	Quote: trying to tie SC and turbo behavior together is a faulty exercise. Without delving into anything technical to explain it, it can be visibly seen in this example: Pace a loaded semi up a big hill on the freeway and listen. He won't downshift, maybe won't even move his accelerator pedal or pick up the rpms but as his engine works against the load of the hill and the exhaust temps rise, you'll hear his turbo spool more and more. A SC is never going to do that. My point is that my experience with my turbos cars (only 1/2 dozen old turbo dodges and now my TT383 in the fury) is that it takes a big hill in order to go into boost. It is pretty easy to get my Fury from cruise @ 20" vac to 'preboost' @10" vac and start to hear the turbos spool up, but I don't go into actual boost unless jab the throttle. ok so how is that different from what I said? "I don't go into actual boost unless jab the throttle" That's the same thing I said. The car won't go into boost until it's under load. Hearing a turbo "spool up" isn't the same as creating boost. Just as the S/C is pushing air because the pulley is being turned, the air is not pushing into the intake at that time. As one lays into the gas or the engine starts to feel load the boost begins to build.

Re: Turbocharging for economy [Re: Pat_Whalen] #1085072 10/04/11 03:44 PM 10/04/11 03:44 PM
Joined: Aug 2011 Posts: 96 Southern USA TN_Michael member
TN_Michael member Joined: Aug 2011 Posts: 96 Southern USA	my CTD gets 24 mpg @ 65 MPH with 2-5 pounds of boost

Re: Turbocharging for economy [Re: Mr.Yuck] #1085073 10/04/11 04:11 PM 10/04/11 04:11 PM
Joined: Nov 2006 Posts: 2,255 IL furious70 top fuel
furious70 top fuel Joined: Nov 2006 Posts: 2,255 IL	Quote: Quote: trying to tie SC and turbo behavior together is a faulty exercise. Without delving into anything technical to explain it, it can be visibly seen in this example: Pace a loaded semi up a big hill on the freeway and listen. He won't downshift, maybe won't even move his accelerator pedal or pick up the rpms but as his engine works against the load of the hill and the exhaust temps rise, you'll hear his turbo spool more and more. A SC is never going to do that. My point is that my experience with my turbos cars (only 1/2 dozen old turbo dodges and now my TT383 in the fury) is that it takes a big hill in order to go into boost. It is pretty easy to get my Fury from cruise @ 20" vac to 'preboost' @10" vac and start to hear the turbos spool up, but I don't go into actual boost unless jab the throttle. ok so how is that different from what I said? "I don't go into actual boost unless jab the throttle" That's the same thing I said. The car won't go into boost until it's under load. Hearing a turbo "spool up" isn't the same as creating boost. Just as the S/C is pushing air because the pulley is being turned, the air is not pushing into the intake at that time. As one lays into the gas or the engine starts to feel load the boost begins to build. The point was a S/C is coupled to crank rpm whereas the turbo has no relation to it at all. You are right that I'm saying like you that the load is often light enough in my car that I don't see boost. 70 Sport Fury 68 Charger 69 Coronet 72 RR

Re: Turbocharging for economy [Re: TN_Michael] #1085074 10/04/11 04:13 PM 10/04/11 04:13 PM
Joined: Nov 2006 Posts: 2,255 IL furious70 top fuel
furious70 top fuel Joined: Nov 2006 Posts: 2,255 IL	Quote: my CTD gets 24 mpg @ 65 MPH with 2-5 pounds of boost Don't bring a diesel into the conversation or everyone will get confused Diesels do not have a throttle blade and therefore don't pull vacuum. Your CTD will also build boost going downhill with your foot off the accelerator. A gas engine will never do that. Diesels also have a very wide range of operable air to fuel ratios, running as lean as 50:1 at idle. 70 Sport Fury 68 Charger 69 Coronet 72 RR

Re: Turbocharging for economy [Re: furious70] #1085075 10/04/11 07:20 PM 10/04/11 07:20 PM
Joined: Aug 2011 Posts: 96 Southern USA TN_Michael member
TN_Michael member Joined: Aug 2011 Posts: 96 Southern USA	Quote: Quote: my CTD gets 24 mpg @ 65 MPH with 2-5 pounds of boost Don't bring a diesel into the conversation or everyone will get confused Diesels do not have a throttle blade and therefore don't pull vacuum. Your CTD will also build boost going downhill with your foot off the accelerator. A gas engine will never do that. Diesels also have a very wide range of operable air to fuel ratios, running as lean as 50:1 at idle. my bad my diesel truck gets more milage than my gas truck even with out boost

Re: Turbocharging for economy [Re: TN_Michael] #1085076 10/04/11 09:57 PM 10/04/11 09:57 PM
Joined: Jan 2003 Posts: 28,067 Irving, TX feets Senior Management
feets Senior Management Joined: Jan 2003 Posts: 28,067 Irving, TX	Leave the Cummins out of this. Mine behaves the same as yours. Now, back to gassers... My hot rod has turbos that most people consider too small for a 440. They will light up and start making boost pretty low. Running 65 mph means pulling 2500 rpm. It does that with 18" of vacuum at 13% throttle according to my EFI datalogs. A slight bit of throttle (opening to 20%) to go around a truck will build 2 to 3 psi boost. At 75 mph the engine is turning about 2800 rpm and is pulling nicely for such a low throttle input. At cruise, I don't see any boost until I'm over 90 mph. At that point the engine is turning 3500 rpm and is starting to work. It is probably the load on the engine that makes the boost. The engine will hold 3500 rpm without boost in 2nd gear. I don't remember my 85 or 86 Shelby Chargers running in boost at a cruise unless I was treating the speed limit as a paltry suggestion. We are brothers and sisters doing time on the planet for better or worse. I'll take the better, if you don't mind. - Stu Harmon

Re: Turbocharging for economy [Re: feets] #1085077 10/05/11 05:51 AM 10/05/11 05:51 AM
Joined: Jun 2008 Posts: 10,847 Oakdale CT gdonovan I Live Here
gdonovan I Live Here Joined: Jun 2008 Posts: 10,847 Oakdale CT	Quote: It is probably the load on the engine that makes the boost. Your engine is turning a LOT of rpm at highway speeds and yes, turbos LOVE load just like the top fuelers. I kept lowering the rear transaxle ratio and the car just kept going faster and quicker. Reliant runs a 2.50 final drive ratio and loafs through the lights at 5200-5300. Daytona was 3.85 but it had overdrive at cruise, off the top of my fuzzy head, 2500 rpm while going 65 sounds about right. Feets was your Shelby Charger with stock or near stock exhaust? Chrysler used the cat & exhaust to limit the turbocharger, Daytona had a 3" system.

Re: Turbocharging for economy [Re: gdonovan] #1085078 10/05/11 09:46 AM 10/05/11 09:46 AM
Joined: Jan 2003 Posts: 24,562 Brookeville, Md Mr.Yuck Not enough dumb comments...yet
Mr.Yuck Not enough dumb comments...yet Joined: Jan 2003 Posts: 24,562 Brookeville, Md	"The point was a S/C is coupled to crank rpm whereas the turbo has no relation to it at all". Yes I know they make boost differently, my point was what we both said... "You are right that I'm saying like you that the load is often light enough in my car that I don't see boost." 6857217-komp.jpg (48 downloads)

Re: Turbocharging for economy [Re: gdonovan] #1085079 10/05/11 11:39 AM 10/05/11 11:39 AM
Joined: Jan 2003 Posts: 28,067 Irving, TX feets Senior Management
feets Senior Management Joined: Jan 2003 Posts: 28,067 Irving, TX	Quote: Feets was your Shelby Charger with stock or near stock exhaust? Chrysler used the cat & exhaust to limit the turbocharger, Daytona had a 3" system. I had stock exhaust on both cars. In fact, with the exception of the basic turbo related mods both cars were bone stock. We are brothers and sisters doing time on the planet for better or worse. I'll take the better, if you don't mind. - Stu Harmon

Re: Turbocharging for economy [Re: feets] #1085080 10/06/11 12:04 AM 10/06/11 12:04 AM
Joined: May 2003 Posts: 6,562 Downtown Roebuck Ont Twostick Still wishing...
Twostick Still wishing... Joined: May 2003 Posts: 6,562 Downtown Roebuck Ont	Picture it this way... if the engine is running, the exhaust turbine is turning which means the compressor is also turning. If that is turning, it is moving air. This is the key, the air is ALREADY moving when it comes into the engine. It doesn't have to go into boost to affect efficiency. Anything that will increase velocity even slightly in the manifold can give better fuel distribution cylinder to cylinder which will make the engine more efficient which could equal better mileage. Kevin

Re: Turbocharging for economy [Re: Twostick] #1085081 10/06/11 11:55 AM 10/06/11 11:55 AM
Joined: Jan 2003 Posts: 28,067 Irving, TX feets Senior Management
feets Senior Management Joined: Jan 2003 Posts: 28,067 Irving, TX	I'm very familiar with that. Again, I've been playing with turbos off and on since 1990. I've tinkered with them constantly for the last decade. You should feel the air moving with a pair of hybrids on a 440. It's a substantial amount of air but the engine still pulls a strong vacuum until it's under load. We are brothers and sisters doing time on the planet for better or worse. I'll take the better, if you don't mind. - Stu Harmon

Re: Turbocharging for economy [Re: feets] #1085082 10/06/11 12:54 PM 10/06/11 12:54 PM
Joined: Nov 2006 Posts: 2,255 IL furious70 top fuel
furious70 top fuel Joined: Nov 2006 Posts: 2,255 IL	Can we explore that a bit more? Yes, the turbos are spinning and moving the air, but if there is a vacuum that means the engine is still doing the work of sucking the air through the throttle opening and valves. How does one quantify the benefit. 'Ram air' at WOT is one thing, but what you're suggesting is that ram air has a real effect on the engine at partial throttle/vacuum conditions. 70 Sport Fury 68 Charger 69 Coronet 72 RR

Re: Turbocharging for economy [Re: furious70] #1085083 10/06/11 01:10 PM 10/06/11 01:10 PM
Joined: Jan 2003 Posts: 28,067 Irving, TX feets Senior Management
feets Senior Management Joined: Jan 2003 Posts: 28,067 Irving, TX	The turbos are moving air at idle. The engine is moving air at idle. What volume of air each is moving is open for discussion. Somebody else can do the math on how much air a 440 moves at 900 rpm. I'm a bit busy today. We are brothers and sisters doing time on the planet for better or worse. I'll take the better, if you don't mind. - Stu Harmon

Re: Turbocharging for economy [Re: Twostick] #1085084 10/06/11 11:24 PM 10/06/11 11:24 PM
Joined: Jan 2005 Posts: 2,540 Milwaukee WI T TRENDZ master
TRENDZ master T Joined: Jan 2005 Posts: 2,540 Milwaukee WI	Quote: Picture it this way... if the engine is running, the exhaust turbine is turning which means the compressor is also turning. If that is turning, it is moving air. This is the key, the air is ALREADY moving when it comes into the engine. It doesn't have to go into boost to affect efficiency. Anything that will increase velocity even slightly in the manifold can give better fuel distribution cylinder to cylinder which will make the engine more efficient which could equal better mileage. Kevin There are so many flaws in this I don't know where to start. First, yes the turbine is spinning. Why? Because of the restriction in the exhaust flow. That in itself is a give and take in fuel economy. The give.....a restriction means less airflow through the engine. Less airflow means less fuel, except,(here's the take) the "in cylinder" mixture gets tainted from the restriction, and weakens the combustion process. There is also parasitic loss. There is no way to spin anything without expending energy. The energy in this case comes from the fuel. Turbos and superchargers don't speed up airflow. They increase density. There is a throttle plate between the compressor and the intake manifold on most gas engines. The throttle plate plays a big role in manifold density. At idle and light cruise there is a vacuum in the manifold. The less vacuum, the higher the load on the engine. More load(more air) equals more fuel. Bottom line is a turbo is an energy exchanger, a machine. You can't convert energy forms without a loss. You wont get more out than you put in. A turbo can make an engine more powerful, but not without more fuel. The only thing that a turbo is intended to do is add air to an engine. If you add air, you need to add fuel. Adding fuel is not the path to economy. "use it 'till it breaks, replace as needed"

Re: Turbocharging for economy [Re: TRENDZ] #1085085 10/07/11 03:14 AM 10/07/11 03:14 AM
Joined: Jan 2003 Posts: 8,180 Detroit, MI CokeBottleKid master
CokeBottleKid master Joined: Jan 2003 Posts: 8,180 Detroit, MI	Quote: I gotta dis-agree with you, Feets. You will never see bsfc numbers in the .4s with any turbo engine(with the exception of direct injected engines). It's not all that uncommon to see .45 in a well thought out n/a engine. The myth of economy with a turbo engine comes from, as previously stated, a smaller engine that is capable of making the hp of a larger engine. If you were to use that smaller engine in boost all the time though, you would be no further ahead in economy. It's the time out of boost with a smaller engine that you see your gains in economy. Listen to this man people, he knows what he's talking about. There's no such thing as turbocharged economy for spark ignition engines. The only way it pans out is as Trendz mentioned, you match its output to a larger N/A engine and compare BSFC under light loads (4 cylinder turbo to 8 cylinder N/A for example). It only pans out because the larger engines have more friction and pumping losses. There are a multi-tude of things you get dinged for in efficiency on a turbo engine. 1. You run less compression: we all know compression = power, but it also SIGNIFICANTLY impacts efficiency, in fact it's one of the largest and most well documented players in efficiency. More compression = more efficiency 2. You run less timing: while under light load (vacuum or low boost) the timing is the same-ish as an N/A engine, when under heavy load (high boost) timing is retarded 10-30 degrees easily, obviously having large impact on efficiency. 3. You run way rich: again while not under boost or under low boost maybe at stoich (14.7:1), but under heavy boost EASILY 10 to 11.5:1. You can't burn more fuel than air so that extra fuel is just going out the exhaust. Plus all the other things Trendz covered such as exhaust restrictions etc. So in short, if you want to build an economical v8, build a high compression N/A motor with low friction (think smallblock).

Re: Turbocharging for economy [Re: TRENDZ] #1085086 10/07/11 06:22 AM 10/07/11 06:22 AM
Joined: Jun 2008 Posts: 10,847 Oakdale CT gdonovan I Live Here
gdonovan I Live Here Joined: Jun 2008 Posts: 10,847 Oakdale CT	Quote: There is no way to spin anything without expending energy. The energy in this case comes from the fuel. Turbochargers are recovering some of lost heat energy in the exhaust stream, unlike a supercharger which is stealing it off the front of the crank. One reason why turbos will always make more power than a supercharger. Top fuel teams were working on turbocharging at one time because the supercharger load was calculated to be as high as 500hp off the front of the crank!

Re: Turbocharging for economy [Re: CokeBottleKid] #1085087 10/07/11 06:42 AM 10/07/11 06:42 AM
Joined: Jun 2008 Posts: 10,847 Oakdale CT gdonovan I Live Here
gdonovan I Live Here Joined: Jun 2008 Posts: 10,847 Oakdale CT	Quote: 1. You run less compression: we all know compression = power, but it also SIGNIFICANTLY impacts efficiency, in fact it's one of the largest and most well documented players in efficiency. More compression = more efficiency Actually, filling the cylinders with boost increases the effective compression ratio. Quote: 2. You run less timing: while under light load (vacuum or low boost) the timing is the same-ish as an N/A engine, when under heavy load (high boost) timing is retarded 10-30 degrees easily, obviously having large impact on efficiency. If you are actually in high boost your looking to make power and fuel economy is clearly a non-issue at this point. A large naturally aspirated engine at WOT making the same power under the same conditions will also have poor economy too. Quote: 3. You run way rich: again while not under boost or under low boost maybe at stoich (14.7:1), but under heavy boost EASILY 10 to 11.5:1. You can't burn more fuel than air so that extra fuel is just going out the exhaust. The same applies to any naturally aspirated engine under WOT. I have run small engines and big engines, I did what I'm told can't be done (towed with turbo 4 engine for 50,000 miles!) and if I had a choice I'd take a well built small displacement engine that was turbocharged. Excellent mpg and more power is just the flick of a switch away. My turbocharged 4 got better mpg while towing a car than my current truck gets empty. That's real world. The other thing you have to calculate is, is it worth it? Slapping a turbo on an existing package isn't going to magically get you better mpg or car makers would be all over it. And how long do you have to drive the thing before you make your money back from the mpg savings to just payoff the turbo setup?

Re: Turbocharging for economy [Re: gdonovan] #1085088 10/07/11 09:33 AM 10/07/11 09:33 AM
Joined: Feb 2003 Posts: 4,953 Houston, Texas TheOtherDodge master
TheOtherDodge master Joined: Feb 2003 Posts: 4,953 Houston, Texas	Talking about a 600 hp application: IMO the biggest benefit in a turbo application is the ability to run a much more numerically lower gear than a N/A motor. Also, I don't think an N/A motor with a fairly healthy cam is going to be as efficient at lower speeds than a relatively "stock" cam that a turbo uses. Finally, a stock type converter can be used vs a higher stall of an NA application.

Re: Turbocharging for economy [Re: gdonovan] #1085089 10/07/11 04:32 PM 10/07/11 04:32 PM
Joined: Dec 2003 Posts: 22,696 Bitopia J jcc If you can't dazzle em with diamonds..
jcc If you can't dazzle em with diamonds.. J Joined: Dec 2003 Posts: 22,696 Bitopia	Quote: Quote: There is no way to spin anything without expending energy. The energy in this case comes from the fuel. Turbochargers are recovering some of lost heat energy in the exhaust stream, unlike a supercharger which is stealing it off the front of the crank. One reason why turbos will always make more power than a supercharger. And to put a real world approx number on that lost heat/energy in the exhaust/radiator/block, its roughly equal to the flywheel horsepower, and if cooling the exhaust temp by using that wasted energy to run a turbo, I'd say a turbo is more econonical to run, but as stated numerous times before not install. Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.

Re: Turbocharging for economy [Re: CokeBottleKid] #1085090 10/07/11 09:04 PM 10/07/11 09:04 PM
Joined: Dec 2006 Posts: 3,533 Indiana F Fury Fan master
Fury Fan master F Joined: Dec 2006 Posts: 3,533 Indiana	Quote: 2. You run less timing: while under light load (vacuum or low boost) the timing is the same-ish as an N/A engine, when under heavy load (high boost) timing is retarded 10-30 degrees easily, obviously having large impact on efficiency. Actually, this is not as cut-dry as that. I hope I can explain it accurately... Ignition advance is required because the mixture does not explode instantaneousy @ spark, but rather as a controlled burn that takes time. As we don't want it burning much after TDC, we must start earlier so that we have complete combustion for the start of the power stroke. More timing is needed as RPM increases becuase there is less time available for the burn event (which still requires about the same amount of time, in comparison). The flame front travels faster from droplet-to-droplet in a denser or more homogeneous mixture (I believe this is an accurate statement). So, the more efficient a cylinder head (think turbulence, swirl, quench) or the more boost you have, the less timing is needed, as the mixture is more homogeneous, and gives better flame travel. that does not necessarily mean the burn is less effective. Excessive timing lead causes pressure to build on the piston while it is travelling upward on the compression stroke - reducing efficiency. To summarize: I don't think we can really compare timing #s between NA and boosted engines as relating to efficiency.

Re: Turbocharging for economy [Re: Fury Fan] #1085091 10/07/11 09:59 PM 10/07/11 09:59 PM
Joined: Dec 2003 Posts: 22,696 Bitopia J jcc If you can't dazzle em with diamonds..
jcc If you can't dazzle em with diamonds.. J Joined: Dec 2003 Posts: 22,696 Bitopia	Quote: The flame front travels faster from droplet-to-droplet in a denser or more homogeneous mixture (I believe this is an accurate statement). For what little I know, I believe you are spot on. However regarding the benefits of "homogeneous mixture", I am not sure how turboing by itself effects that. I will admit mixture is denser, but not sure if it travels faster, mainly because of high residual exhaust back pressure, and not sure if that also makes for a more homogeneous mixture, which would mean high rpms are more homogenous then lower? Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.

Re: Turbocharging for economy [Re: jcc] #1085092 10/08/11 02:42 AM 10/08/11 02:42 AM
Joined: May 2003 Posts: 6,562 Downtown Roebuck Ont Twostick Still wishing...
Twostick Still wishing... Joined: May 2003 Posts: 6,562 Downtown Roebuck Ont	I think everyone here is assuming that there is no boost without positive pressure. Just because a turbo'd engine cruises with vacuum doesn't mean it isn't seeing boost. Say a NA engine cruised with 18" of vac. Now put a turbo on it under the same conditions but now it cruises with 17". The engine is now running with whatever 1" equals for boost. With a NA type part throttle tune you have now just leaned it out at cruise. Maybe reaching here a bit but I think technically there is a case to be made for better fuel efficiency. Kevin

Re: Turbocharging for economy [Re: Twostick] #1085093 10/08/11 04:23 PM 10/08/11 04:23 PM
Joined: Jan 2005 Posts: 2,540 Milwaukee WI T TRENDZ master
TRENDZ master T Joined: Jan 2005 Posts: 2,540 Milwaukee WI	No. An engine's manifold pressure/vacuum indicates load. If you apply the same load, you get the same vacuum, no matter how much pressure is in front of the throttle blade. You're working the equation from the wrong angle. Manifold pressure is resultant. You cruise at say 65mph. At 65mph, your engine may make 12" of vacuum on a flat road, 20" down hill and 4" up a hill. You aren't after a vacuum number, you're after 65mph, and the throttle plate is what you change to achieve that goal. Your example assumes the throttle plate is in a fixed position. If it were, the denser air would pass the throttle plate and speed up the engine. Cruise speed would go up,as would fuel consumption. "use it 'till it breaks, replace as needed"

Re: Turbocharging for economy [Re: TRENDZ] #1085094 10/08/11 09:30 PM 10/08/11 09:30 PM
Joined: May 2003 Posts: 6,562 Downtown Roebuck Ont Twostick Still wishing...
Twostick Still wishing... Joined: May 2003 Posts: 6,562 Downtown Roebuck Ont	I agree with most of your explanation for manifold pressure but I'm pretty sure you have still made my point. (I think )If the pressure above the blade has no bearing then at our given 65 mph level road load, the blade angle will still be the same as NA or effectively fixed. The denser air will in fact go around the blade but it won't be carrying any more fuel than it would NA because a carb meters fuel based on air volume not air density and the mix will be slightly leaner. Kind of like the difference between 2500' DA and say -500' DA with it jetted for 2500'. Would you agree that if you could cruise steady state at a -500 DA while jetted for a higher DA that there would be the potential for a slight increase in fuel efficiency? And just to be clear, when I say I think a boosted engine can be more fuel efficient than the same engine NA I'm talking single digit % increase. Kevin

Re: Turbocharging for economy [Re: Twostick] #1085095 10/08/11 10:49 PM 10/08/11 10:49 PM
Joined: Jan 2003 Posts: 8,165 Plymouth, MI Blusmbl master
Blusmbl master Joined: Jan 2003 Posts: 8,165 Plymouth, MI	Quote: And just to be clear, when I say I think a boosted engine can be more fuel efficient than the same engine NA I'm talking single digit % increase. With your version explained you're "cheating" by not having the same tailpipe air/fuel ratio. It would only potentially make a difference at higher loads, it would definitely not be true from an overall perspective. You could run a speed/load map of an n/a engine and the same engine with a turbo added, and there may be a small number of points where the turbo engine is more efficient because it could make a higher torque value at a given engine speed, but it would most likely be at higher loads, if any at all. Adding the turbo alone is going to decrease fuel economy, between the weight added to the vehicle and the increased pumping losses with the turbo in the exhaust stream. I would not be adding a turbo to a motor thinking fuel economy would improve. Fun factor, yes. Fuel consumption, no. '18 Ford Raptor, random motorcycles, 1968 Plymouth Fury III - 11.37 @ 118

Re: Turbocharging for economy [Re: Twostick] #1085096 10/09/11 01:12 AM 10/09/11 01:12 AM
Joined: Jan 2005 Posts: 2,540 Milwaukee WI T TRENDZ master
TRENDZ master T Joined: Jan 2005 Posts: 2,540 Milwaukee WI	Quote: I agree with most of your explanation for manifold pressure but I'm pretty sure you have still made my point. (I think )If the pressure above the blade has no bearing then at our given 65 mph level road load, the blade angle will still be the same as NA or effectively fixed. The denser air will in fact go around the blade but it won't be carrying any more fuel than it would NA because a carb meters fuel based on air volume not air density and the mix will be slightly leaner. Kind of like the difference between 2500' DA and say -500' DA with it jetted for 2500'. Would you agree that if you could cruise steady state at a -500 DA while jetted for a higher DA that there would be the potential for a slight increase in fuel efficiency? I come from a fuel injected world, where more air in equals more fuel in. So, you're saying that this hypothetical engine's vacuum changes because it's getting more air, yet your explaination says," A carb meters fuel based on air volume.... My question is, where is the extra air in the engine coming from if a larger volume of air is not going through the carb? Do you think density has no bearing on a venturi? Do you think a carb's throttle angle is directly proportionate to fuel flow? Would you tune your carb to run richer than needed in one spot so you could make it run correct in another and expect a more fuel efficient engine? How about making it run clean everywhere? Your explaination seems to indicate it cant be done. Last edited by TRENDZ; 10/09/11 01:31 AM. "use it 'till it breaks, replace as needed"

Re: Turbocharging for economy [Re: TheOtherDodge] #1085097 10/09/11 01:29 AM 10/09/11 01:29 AM
Joined: Jan 2005 Posts: 2,540 Milwaukee WI T TRENDZ master
TRENDZ master T Joined: Jan 2005 Posts: 2,540 Milwaukee WI	Quote: Talking about a 600 hp application: IMO the biggest benefit in a turbo application is the ability to run a much more numerically lower gear than a N/A motor. Also, I don't think an N/A motor with a fairly healthy cam is going to be as efficient at lower speeds than a relatively "stock" cam that a turbo uses. Finally, a stock type converter can be used vs a higher stall of an NA application. This is the best argument for the turbo engine. My understanding is(and I could be wrong here) that the OP was thinking of adding a turbo to an existing engine to gain fuel economy not to add power. My stance is adding a turbo to an engine wont make the engine more fuel efficient. But as you say here the car can now be changed to take advantage of the turbo engine characteristics. I agree, if you want a 600hp car this is the way to go. If you want a 400hp car,not so much. "use it 'till it breaks, replace as needed"

Re: Turbocharging for economy [Re: TRENDZ] #1085098 10/09/11 02:23 AM 10/09/11 02:23 AM
Joined: May 2003 Posts: 6,562 Downtown Roebuck Ont Twostick Still wishing...
Twostick Still wishing... Joined: May 2003 Posts: 6,562 Downtown Roebuck Ont	Quote: Quote: I agree with most of your explanation for manifold pressure but I'm pretty sure you have still made my point. (I think )If the pressure above the blade has no bearing then at our given 65 mph level road load, the blade angle will still be the same as NA or effectively fixed. The denser air will in fact go around the blade but it won't be carrying any more fuel than it would NA because a carb meters fuel based on air volume not air density and the mix will be slightly leaner. Kind of like the difference between 2500' DA and say -500' DA with it jetted for 2500'. Would you agree that if you could cruise steady state at a -500 DA while jetted for a higher DA that there would be the potential for a slight increase in fuel efficiency? I come from a fuel injected world, where more air in equals more fuel in. So, you're saying that this hypothetical engine's vacuum changes because it's getting more air, yet your explaination says," A carb meters fuel based on air volume.... My question is, where is the extra air in the engine coming from if a larger volume of air is not going through the carb? Do you think density has no bearing on a venturi? Do you think a carb's throttle angle is directly proportionate to fuel flow? Would you tune your carb to run richer than needed in one spot so you could make it run correct in another and expect a more fuel efficient engine? How about making it run clean everywhere? Your explaination seems to indicate it cant be done. If density had a bearing on a venturi, you wouldn't have to jet a carb up for "good" air. With all due respect an EFI setup has very little in common with a carb so to answer your question if I tuned a carb for max cruise fuel mileage it would be a given that it might not perform as well at WOT. That's the beauty of EFI, you can optimize for all loads or throttle positions. With a carb you can get it dead nuts for a VERY narrow range. Anything outside that at best will just be sorta close. Kevin

Re: Turbocharging for economy [Re: Twostick] #1085099 10/09/11 09:05 AM 10/09/11 09:05 AM
Joined: Jan 2005 Posts: 2,540 Milwaukee WI T TRENDZ master
TRENDZ master T Joined: Jan 2005 Posts: 2,540 Milwaukee WI	Well, you got me there. So the basic idea here is add a turbo, and as long as your fuel metering is wrong, you will increase your mileage. "use it 'till it breaks, replace as needed"

Re: Turbocharging for economy [Re: Blusmbl] #1085100 10/09/11 09:15 AM 10/09/11 09:15 AM
Joined: Jun 2008 Posts: 10,847 Oakdale CT gdonovan I Live Here
gdonovan I Live Here Joined: Jun 2008 Posts: 10,847 Oakdale CT	Quote: Adding the turbo alone is going to decrease fuel economy, between the weight added to the vehicle and the increased pumping losses with the turbo in the exhaust stream. All one has to do is compare factory engines that are mostly the same aside from turbo setups. Chrysler had both in 1989- An N/A 2.5 and a turbocharged 2.5. For all intents and purposes the main differences between the two is a touch more static compression with the N/A motor, the N/A motor has a cam with slightly more overlap. Even though the turbomotor has a far superior intake setup (MPI vs craptastic TBI) the N/A motor was well noted for its better MPG. 21-36 mpg for the N/A motor, 18-26 mpg for the turbo. These numbers are from the Federal MPG website with the same vehicle with manual transmissions. You are not going to get better mpg slapping on a turbo without reduction of displacement, period.

Re: Turbocharging for economy [Re: gdonovan] #1085101 10/09/11 10:51 AM 10/09/11 10:51 AM
Joined: Feb 2003 Posts: 4,953 Houston, Texas TheOtherDodge master
TheOtherDodge master Joined: Feb 2003 Posts: 4,953 Houston, Texas	"You are not going to get better mpg slapping on a turbo without reduction of displacement, period." Once again, unless we are talking about a stockish type motor with no stall and 3.23 gearing, I 100% disagree. Less converter, less gearing, = less rpm on the motor. Your example is from 1989 and not only is FI much better today than back then, you are talking about motors making no more than 225 hp. Does anyone ever wonder why all the new high hp production cars are forced induction?

Re: Turbocharging for economy [Re: TheOtherDodge] #1085102 10/09/11 11:28 AM 10/09/11 11:28 AM
Joined: Jun 2008 Posts: 10,847 Oakdale CT gdonovan I Live Here
gdonovan I Live Here Joined: Jun 2008 Posts: 10,847 Oakdale CT	Quote: Your example is from 1989 and not only is FI much better today than back then, you are talking about motors making no more than 225 hp. The fuel injection and intake on the 89 turbo motor is SIGNIFICANTLY better than the 89 non-turbo motor. And yet the N/A motor gets better MPG. The real world results speak for themselves. This will only be compounded by modern technology, any improvement that can be applied to a forced inducted engine can be applied to a N/A engine as well. Rpm isn't necessarily the killer of MPG (I have driven 1.8l Acuras that buzzed down the highway at much higher rates than a typical mopar and get good MPG) Higher load on the motor = more fuel consumption. Quote: Does anyone ever wonder why all the new high hp production cars are forced induction? Doh! Perhaps because more power can't be extracted by N/A means due to running afoul of federal emissions.

Re: Turbocharging for economy [Re: TRENDZ] #1085103 10/09/11 03:50 PM 10/09/11 03:50 PM
Joined: Nov 2006 Posts: 2,255 IL furious70 top fuel
furious70 top fuel Joined: Nov 2006 Posts: 2,255 IL	Quote: Well, you got me there. So the basic idea here is add a turbo, and as long as your fuel metering is wrong, you will increase your mileage. and if we 'stumble' upon this little carb tuning secret, why wouldn't we apply it to the NA engine as well and be back to square 1? If we're gonna run the turbo engine leaner than it should be, why not do the same to the NA? 70 Sport Fury 68 Charger 69 Coronet 72 RR

Re: Turbocharging for economy [Re: furious70] #1085104 10/09/11 03:54 PM 10/09/11 03:54 PM
Joined: Feb 2003 Posts: 4,953 Houston, Texas TheOtherDodge master
TheOtherDodge master Joined: Feb 2003 Posts: 4,953 Houston, Texas	"Rpm isn't necessarily the killer of MPG (I have driven 1.8l Acuras that buzzed down the highway at much higher rates than a typical mopar and get good MPG)" Really? that 1.8L Acura got what mpg at that "buzzin" rpm vs what 1.8L Mopar at "normal" rpms? Please give me an example to help me believe this.

Re: Turbocharging for economy [Re: TheOtherDodge] #1085105 10/09/11 03:56 PM 10/09/11 03:56 PM
Joined: Feb 2003 Posts: 4,953 Houston, Texas TheOtherDodge master
TheOtherDodge master Joined: Feb 2003 Posts: 4,953 Houston, Texas	"Doh! Perhaps because more power can't be extracted by N/A means due to running afoul of federal emissions. " Really? I guess that big inch Viper didn't pass emissions? And you don't think driveability and mpg has no factor in the decision to go with forced induction? Ok. Not going to argue as we all have our own opinions.

Re: Turbocharging for economy [Re: gdonovan] #1085106 10/09/11 04:15 PM 10/09/11 04:15 PM
Joined: Nov 2003 Posts: 1,969 Chandler, AZ Duner top fuel
Duner top fuel Joined: Nov 2003 Posts: 1,969 Chandler, AZ	Don't forget that in the 80's - the answer to turbo tuning was to take away timing and throw fuel at it. We've progressed well beyond that now, where we can have lots of timing and only back it down when actually in boost. That little change helps fuel efficiency/mileage by a huge amount. Too bad we can't get Smokey Yunick in this conversation....

Re: Turbocharging for economy [Re: furious70] #1085107 10/09/11 04:51 PM 10/09/11 04:51 PM
Joined: May 2003 Posts: 6,562 Downtown Roebuck Ont Twostick Still wishing...
Twostick Still wishing... Joined: May 2003 Posts: 6,562 Downtown Roebuck Ont	Quote: Quote: Well, you got me there. So the basic idea here is add a turbo, and as long as your fuel metering is wrong, you will increase your mileage. and if we 'stumble' upon this little carb tuning secret, why wouldn't we apply it to the NA engine as well and be back to square 1? If we're gonna run the turbo engine leaner than it should be, why not do the same to the NA? Been done already. It was called Leanburn. Good idea. Really bad execution. Kevin

Re: Turbocharging for economy [Re: TheOtherDodge] #1085108 10/09/11 05:28 PM 10/09/11 05:28 PM
Joined: Jun 2008 Posts: 10,847 Oakdale CT gdonovan I Live Here
gdonovan I Live Here Joined: Jun 2008 Posts: 10,847 Oakdale CT	Quote: "Doh! Perhaps because more power can't be extracted by N/A means due to running afoul of federal emissions. " Really? I guess that big inch Viper didn't pass emissions? And you don't think driveability and mpg has no factor in the decision to go with forced induction? Ok. Not going to argue as we all have our own opinions. Now your trying to muddy things up- The Viper is a V-10 because of federal emissions, the same reason they are supercharging V8 packages. Big wide cylinders increase hydrocarbon emissions around the edges of the pistons. Chrysler (and other car makers) went to "extra cylinders" to reduce this area and better control emissions. Also exactly why piston rings are so close to piston tops now. The Challenger, Mustang and Camaro are working within the confines of a V8 package. Big cams are not going to pass federal emissions, hence forced induction in an effort to produce more power within a given package. Look it up, I'm not going to do the research for you. This has been well covered.

Re: Turbocharging for economy [Re: Duner] #1085109 10/09/11 05:31 PM 10/09/11 05:31 PM
Joined: Jun 2008 Posts: 10,847 Oakdale CT gdonovan I Live Here
gdonovan I Live Here Joined: Jun 2008 Posts: 10,847 Oakdale CT	Quote: Don't forget that in the 80's - the answer to turbo tuning was to take away timing and throw fuel at it. Still has to pass federal emissions standards which are much higher than state. Feel free to cite another example where a turbocharged engine gets better mpg than its naturally aspirated counterpart of the same displacement. . I pointed out a clean example and so far got nothing but hot air in return.

Re: Turbocharging for economy [Re: TheOtherDodge] #1085110 10/09/11 05:35 PM 10/09/11 05:35 PM
Joined: Jun 2008 Posts: 10,847 Oakdale CT gdonovan I Live Here
gdonovan I Live Here Joined: Jun 2008 Posts: 10,847 Oakdale CT	Quote: Really? that 1.8L Acura got what mpg at that "buzzin" rpm vs what 1.8L Mopar at "normal" rpms? Please give me an example to help me believe this. http://www.fueleconomy.gov/feg/calculatorCompareSideBySidePopUp.jsp?column=1&id=6443 You are well aware there is no comparable "1.8 mopar" engine made during this time frame. 6863571-mpg.jpg (32 downloads)

Re: Turbocharging for economy [Re: gdonovan] #1085111 10/09/11 05:47 PM 10/09/11 05:47 PM
Joined: Nov 2003 Posts: 1,969 Chandler, AZ Duner top fuel
Duner top fuel Joined: Nov 2003 Posts: 1,969 Chandler, AZ	I don't really understand your argumentative tack... I just pointed out why in the 80s the turbo'd engine would get worse mileage. Other than when in boost - a "modern" engine will make the same mileage NA as boosted when not in boost. They didn't have as much control over things in the 80s - so it wasn't the case. They put more fuel to it and retarded the timing to make it work hard enough to burn the fuel at idle to pass emissions. That's just how they did it in "the old days". I don't really care about your argument. I understand that the REASON manufacturers add turbos is for PERFORMANCE. Feel free to expend as much energy supporting the argument as you please - I have no dog in this fight.

Re: Turbocharging for economy [Re: Duner] #1085112 10/09/11 06:23 PM 10/09/11 06:23 PM
Joined: Jun 2008 Posts: 10,847 Oakdale CT gdonovan I Live Here
gdonovan I Live Here Joined: Jun 2008 Posts: 10,847 Oakdale CT	Quote: I just pointed out why in the 80s the turbo'd engine would get worse mileage. Other than when in boost - a "modern" engine will make the same mileage NA as boosted when not in boost. Your position makes no sense- The turbo motor passes Federal emissions (destroying the "dumps fuel" argument) has better intake and fueling than the N/A counterpart and yet the N/A motor gets better MPG. The turbocharged engine WILL get worse MPG regardless of electronics for the same displacement. The exhaust restrictions alone due to the turbo will cause some loss of MPG. Oh, and by the way? If you compare turbocharged 2.4 engine with the non-turbocharged version you will see that the non turbocharged version gets better mpg. One can assume that 2006 vintage electronics are somewhat better than what was used in 1989. Quote: They put more fuel to it and retarded the timing to make it work hard enough to burn the fuel at idle to pass emissions. That's just how they did it in "the old days". You keep stating this without a shred of proof. I have access to the code and can point out that at times the turbo engines ran as much as 54 degrees of timing at cruise. This can be confirmed with a Snap On MT 2500 scanner on an average turbo Mopar. My point (again) is that you cannot increase mpg by adding a turbo to an engine package (which is the original intent of discussion is it not?). Only by decreasing the displacement will you gain any mpg when adding a turbocharger. The turbocharger will allow you cruise with a "small" engine and have a "larger" engine when desirable.

Re: Turbocharging for economy [Re: gdonovan] #1085113 10/09/11 06:30 PM 10/09/11 06:30 PM
Joined: Nov 2003 Posts: 1,969 Chandler, AZ Duner top fuel
Duner top fuel Joined: Nov 2003 Posts: 1,969 Chandler, AZ	OK, I see that reading comprehension isn't your strong point - and that you continue to want to be argumentative. Go ahead and argue with yourself. I'm finished conversing with you on any level.

Re: Turbocharging for economy [Re: gdonovan] #1085114 10/10/11 12:07 AM 10/10/11 12:07 AM
Joined: Feb 2003 Posts: 4,953 Houston, Texas TheOtherDodge master
TheOtherDodge master Joined: Feb 2003 Posts: 4,953 Houston, Texas	"You are well aware there is no comparable "1.8 mopar" engine made during this time frame." You are the one that made the statement "Rpm isn't necessarily the killer of MPG (I have driven 1.8l Acuras that buzzed down the highway at much higher rates than a typical mopar and get good MPG)" Your own admission that there are no comparable mopar motors renders your statement invalid.

Re: Turbocharging for economy [Re: TheOtherDodge] #1085115 10/10/11 02:17 AM 10/10/11 02:17 AM
Joined: Nov 2006 Posts: 2,255 IL furious70 top fuel
furious70 top fuel Joined: Nov 2006 Posts: 2,255 IL	the new 3.5 ecoboost engine is something worth bringing up in this context....I'm not sure if the 3.7l NA is also direct injection? 70 Sport Fury 68 Charger 69 Coronet 72 RR

Re: Turbocharging for economy [Re: TheOtherDodge] #1085116 10/10/11 06:31 AM 10/10/11 06:31 AM
Joined: Jun 2008 Posts: 10,847 Oakdale CT gdonovan I Live Here
gdonovan I Live Here Joined: Jun 2008 Posts: 10,847 Oakdale CT	Quote: "You are well aware there is no comparable "1.8 mopar" engine made during this time frame." You are the one that made the statement "Rpm isn't necessarily the killer of MPG (I have driven 1.8l Acuras that buzzed down the highway at much higher rates than a typical mopar and get good MPG)" Your own admission that there are no comparable mopar motors renders your statement invalid. It also states "typical mopar" if you are going to nitpick and is a true statement as I have driven a large number of mopars and none of them turned as high an rpm as the Acura did. A trade off for having such a small displacement I'm sure. There is a 1.8 mopar engine made now (in the caliber) but since I have no idea what it turns for rpm going down the highway can offer no opinion. It came out about the same time I retired from Chrysler. A quick google search states the acura turns 4000-4200 rpm doing 70 down the interstate which is 2000 rpm higher than my Ram and 1500 rpm higher than my Shelby Daytona. The point still stands, rpm isn;t necessarily the killer of mpg with a real world example provided.

Re: Turbocharging for economy [Re: gdonovan] #1085117 10/10/11 09:55 AM 10/10/11 09:55 AM
Joined: Feb 2003 Posts: 4,953 Houston, Texas TheOtherDodge master
TheOtherDodge master Joined: Feb 2003 Posts: 4,953 Houston, Texas	"which is 2000 rpm higher than my Ram" Really????? You care comparing it to a truck that is probably at least 2000 lbs heavier with a V8? Ok, enjoy! Im done with you too!

Re: Turbocharging for economy [Re: furious70] #1085118 10/10/11 10:27 AM 10/10/11 10:27 AM
Joined: Jan 2003 Posts: 8,165 Plymouth, MI Blusmbl master
Blusmbl master Joined: Jan 2003 Posts: 8,165 Plymouth, MI	Quote: the new 3.5 ecoboost engine is something worth bringing up in this context....I'm not sure if the 3.7l NA is also direct injection? It's a great example. The 3.7 n/a motor gets better economy than the 3.5 ecoboost... http://www.ford.com/trucks/f150/specifications/engine/ You don't turbocharge engines for a fuel economy improvement. If you did, manufacturers would have turbos on everything... '18 Ford Raptor, random motorcycles, 1968 Plymouth Fury III - 11.37 @ 118

Re: Turbocharging for economy [Re: Blusmbl] #1085119 10/10/11 03:40 PM 10/10/11 03:40 PM
Joined: Nov 2006 Posts: 2,255 IL furious70 top fuel
furious70 top fuel Joined: Nov 2006 Posts: 2,255 IL	Quote: Quote: the new 3.5 ecoboost engine is something worth bringing up in this context....I'm not sure if the 3.7l NA is also direct injection? It's a great example. The 3.7 n/a motor gets better economy than the 3.5 ecoboost... http://www.ford.com/trucks/f150/specifications/engine/ You don't turbocharge engines for a fuel economy improvement. If you did, manufacturers would have turbos on everything... And it also proves the real world advantage is that the 3.5 ecoboost provides more torque over a broader rpm range and better mpg than the 5.0L does. This other side argument is silly IMO and I've never heard it argued before that same displacement, same stockish configuration and somehow the turbo engine gets better mpg. 3.5 ecoboost > 5.0L is the real takeaway. 70 Sport Fury 68 Charger 69 Coronet 72 RR

Re: Turbocharging for economy [Re: furious70] #1085120 10/10/11 04:45 PM 10/10/11 04:45 PM
Joined: Jun 2008 Posts: 10,847 Oakdale CT gdonovan I Live Here
gdonovan I Live Here Joined: Jun 2008 Posts: 10,847 Oakdale CT	Quote: And it also proves the real world advantage is that the 3.5 ecoboost provides more torque over a broader rpm range and better mpg than the 5.0L does. This other side argument is silly IMO and I've never heard it argued before that same displacement, same stockish configuration and somehow the turbo engine gets better mpg. 3.5 ecoboost > 5.0L is the real takeaway. Careful, I have pointed that out several times in this thread and got nothing but flack for it.

Re: Turbocharging for economy [Re: TheOtherDodge] #1085121 10/10/11 05:07 PM 10/10/11 05:07 PM
Joined: Jun 2008 Posts: 10,847 Oakdale CT gdonovan I Live Here
gdonovan I Live Here Joined: Jun 2008 Posts: 10,847 Oakdale CT	Quote: "which is 2000 rpm higher than my Ram" Really????? You care comparing it to a truck that is probably at least 2000 lbs heavier with a V8? Ok, enjoy! Im done with you too! "Typical Mopar" was clearly stated alongside another known quantitys for points of reference. Thanks for contributing to this discussion.

Re: Turbocharging for economy [Re: gdonovan] #1085122 10/10/11 09:36 PM 10/10/11 09:36 PM
Joined: Jan 2003 Posts: 28,067 Irving, TX feets Senior Management
feets Senior Management Joined: Jan 2003 Posts: 28,067 Irving, TX	Look, guys, it's not going to happen. Dropping a turbo on an otherwise non-turbo setup WILL NOT increase efficiency. Now, quit all the attempts at trickery and twisting each others' words. As a collective, you've managed to make this thread no longer worth reading. We are brothers and sisters doing time on the planet for better or worse. I'll take the better, if you don't mind. - Stu Harmon

Re: Turbocharging for economy [Re: feets] #1085123 10/10/11 10:17 PM 10/10/11 10:17 PM
Joined: Feb 2003 Posts: 4,953 Houston, Texas TheOtherDodge master
TheOtherDodge master Joined: Feb 2003 Posts: 4,953 Houston, Texas	Hey Feets, the answer is yes and no. Which you do you think will get better gas mileage? 1. 400 inch motor, 4.56 gear, 5000 stall, big cam. 2. 400 inch motor, 3.55 gear, 2500 stall, small cam, 76 mm turbo. Everything else is identical with the exception of noted above. I am curious as to your reply. Whatever your reply, I won't dispute it. My point is that with a turbo (and my example is based on a 600 hp combo, not a stockish type setup) there is the ability to drop rpms that will in turn give the increased gas mileage. A poster replied to my statement and claimed that dropping rpms will not affect gas mileage then attempted to compare a 1.8L motor to a typical Mopar motor (even though at his on admission there was not a compareable motor) and then to a Dodge Ram truck! I didn't make any of that up! It is all on this post!

Re: Turbocharging for economy [Re: TheOtherDodge] #1085124 10/10/11 11:10 PM 10/10/11 11:10 PM
Joined: May 2003 Posts: 6,562 Downtown Roebuck Ont Twostick Still wishing...
Twostick Still wishing... Joined: May 2003 Posts: 6,562 Downtown Roebuck Ont	Quote: Hey Feets, the answer is yes and no. Which you do you think will get better gas mileage? 1. 400 inch motor, 4.56 gear, 5000 stall, big cam. 2. 400 inch motor, 3.55 gear, 2500 stall, small cam, 76 mm turbo. Everything else is identical with the exception of noted above. I am curious as to your reply. I think the premise is identical engine, just add turbo. I still maintain that with blow-thru carb wet manifold induction and an appropriate cam ie stock type, boost theoretically could do slightly better on fuel because it could help an OEM manifold with fuel distribution and perhaps induce/enhance swirl in the chamber when the intake valve opens. Real world? Certainly not enough to warrant the cost. David Gardiner is a friend of mine in the R+D biz that has done all manner of automotive fuel research and is published in the SAE. He is with Nexum Research http://www.nexumresearch.com/publications.html and I'll give him a call this week and get a scientific type opinion. I'll specify a 440 Mopar (he's a Mopar guy) and see what he says. Kevin

Re: Turbocharging for economy [Re: Twostick] #1085125 10/11/11 06:22 AM 10/11/11 06:22 AM
Joined: Jun 2008 Posts: 10,847 Oakdale CT gdonovan I Live Here
gdonovan I Live Here Joined: Jun 2008 Posts: 10,847 Oakdale CT	Quote: Quote: Hey Feets, the answer is yes and no. Which you do you think will get better gas mileage? 1. 400 inch motor, 4.56 gear, 5000 stall, big cam. 2. 400 inch motor, 3.55 gear, 2500 stall, small cam, 76 mm turbo. Everything else is identical with the exception of noted above. I am curious as to your reply. I think the premise is identical engine, just add turbo. Exactly, which is the original posters intent and what we were discussing! I'll answer the question for him though- The motor with the 76mm turbo will get better mpg since it has a mellower cam, milder gear and less stall on the converter.

Re: Turbocharging for economy [Re: feets] #1085126 10/11/11 12:03 PM 10/11/11 12:03 PM
Joined: Dec 2003 Posts: 22,696 Bitopia J jcc If you can't dazzle em with diamonds..
jcc If you can't dazzle em with diamonds.. J Joined: Dec 2003 Posts: 22,696 Bitopia	Quote: Look, guys, it's not going to happen. Dropping a turbo on an otherwise non-turbo setup WILL NOT increase efficiency. Now, quit all the attempts at trickery and twisting each others' words. As a collective, you've managed to make this thread no longer worth reading. , Regardless, heat is power, heat lost thru the exhaust is wasted power, heat used to turn a turbo, which then reduces exhaust temp, (and we all know energy is only converted) and adds other benefits, increases effiency. In WW2, millitary aircraft started to use "turbo compounders", which used the wasted exhaust heat/energy to spin a turbo that was then connected to the shaft output, for added power of nearly 200hp. Before anyone throws up their hands, what am I missing? Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.

Re: Turbocharging for economy [Re: TheOtherDodge] #1085127 10/11/11 02:14 PM 10/11/11 02:14 PM
Joined: Jan 2003 Posts: 28,067 Irving, TX feets Senior Management
feets Senior Management Joined: Jan 2003 Posts: 28,067 Irving, TX	Quote: Hey Feets, the answer is yes and no. Which you do you think will get better gas mileage? 1. 400 inch motor, 4.56 gear, 5000 stall, big cam. 2. 400 inch motor, 3.55 gear, 2500 stall, small cam, 76 mm turbo. Everything else is identical with the exception of noted above. EVERYTHING IDENTICAL. EVERYTHING! CHASSIS, ENGINE, TRANS, GEARS, EVERYTHING! IT WILL NOT MAKE AN IMPROVEMENT! Now, quit changing combinations. It was a simple question. Will adding a turbo increase efficiency? NO, IT WILL NOT! Now, if you toss everything out the window and make an entirely new package bumper to bumper you can build a package to suit your prefrences. That's not what this topic was about. Some of you freaks just don't get it. You can't get something for nothing. Spinning a turbo consumes energy. to take advantage of it you have to change the combination. POW! It's no longer the same package and therefore out of the realm of this topic. Some of you people need to pull your heads out of your collective arses and THINK! There is no free lunch. Cause and effect. Go all the way through cause and effect WITHOUT changing your combination. I'm out of this one. We are brothers and sisters doing time on the planet for better or worse. I'll take the better, if you don't mind. - Stu Harmon

Re: Turbocharging for economy [Re: feets] #1085128 10/11/11 03:31 PM 10/11/11 03:31 PM
Joined: Jan 2005 Posts: 2,540 Milwaukee WI T TRENDZ master
TRENDZ master T Joined: Jan 2005 Posts: 2,540 Milwaukee WI	Now you guys went and made him angry. "use it 'till it breaks, replace as needed"

Re: Turbocharging for economy [Re: TRENDZ] #1085129 10/11/11 03:56 PM 10/11/11 03:56 PM
Joined: Nov 2003 Posts: 1,969 Chandler, AZ Duner top fuel
Duner top fuel Joined: Nov 2003 Posts: 1,969 Chandler, AZ	OK? Now what? OK, if we're gong to play THAT game: Cause and effect.... I put a turbo on my truck. I didn't change the programming in the PCM for a turbo, so when I'm not in boost it doesn't know it has a turbo on it. I get better fuel mileage now. That's cause and effect. Yeah, I already told you guys WHY, but apparently it was supposed to COST me fuel mileage and it didn't. I don't believe the efficiency changed one single bit when I'm not in boost.

Re: Turbocharging for economy [Re: feets] #1085130 10/11/11 04:35 PM 10/11/11 04:35 PM
Joined: Feb 2003 Posts: 4,953 Houston, Texas TheOtherDodge master
TheOtherDodge master Joined: Feb 2003 Posts: 4,953 Houston, Texas	Quote: I'm out of this one. Maybe your blood pressure will go down some then! Geez, it's just a web board with a question...

Re: Turbocharging for economy [Re: Duner] #1085131 10/11/11 05:03 PM 10/11/11 05:03 PM
Joined: Nov 2006 Posts: 2,255 IL furious70 top fuel
furious70 top fuel Joined: Nov 2006 Posts: 2,255 IL	Quote: OK? Now what? OK, if we're gong to play THAT game: Cause and effect.... I put a turbo on my truck. I didn't change the programming in the PCM for a turbo, so when I'm not in boost it doesn't know it has a turbo on it. I get better fuel mileage now. That's cause and effect. Yeah, I already told you guys WHY, but apparently it was supposed to COST me fuel mileage and it didn't. I don't believe the efficiency changed one single bit when I'm not in boost. you already said it was cuz you started [Edited by Moparts - Family Friendly Site - Keep it clean] footing the truck vs how you drove it b4. That's a different argument that states changing your driving characteristics can actually effect mpg. Anyone going to argue that one and say that there's less pumping losses at WOT so you should get better mpg by hammering on it? 70 Sport Fury 68 Charger 69 Coronet 72 RR

Re: Turbocharging for economy [Re: furious70] #1085132 10/11/11 06:07 PM 10/11/11 06:07 PM
Joined: Nov 2003 Posts: 1,969 Chandler, AZ Duner top fuel
Duner top fuel Joined: Nov 2003 Posts: 1,969 Chandler, AZ	I don't think it hurt the mileage by putting a turbo in the exhaust path - especially compared to the restrictive stock setup vs the turbo and big exhaust. That's all I am really trying to get across. Then again, I'm not driving an antique with a carbentator either.

Re: Turbocharging for economy [Re: Duner] #1085133 10/11/11 09:40 PM 10/11/11 09:40 PM
Joined: Jan 2003 Posts: 24,562 Brookeville, Md Mr.Yuck Not enough dumb comments...yet
Mr.Yuck Not enough dumb comments...yet Joined: Jan 2003 Posts: 24,562 Brookeville, Md	I think the main thing is A. He WILL NOT improve mpg w/ a turbo but B. he WILL improve his HP and torque.

Re: Turbocharging for economy [Re: Mr.Yuck] #1085134 10/17/11 12:51 PM 10/17/11 12:51 PM
Joined: Dec 2003 Posts: 22,696 Bitopia J jcc If you can't dazzle em with diamonds..
jcc If you can't dazzle em with diamonds.. J Joined: Dec 2003 Posts: 22,696 Bitopia	I guess the First law of thermodynmics does not apply to turbos. I always thought heat/energy sent out the exhaust was wasted and deducted from the total efficency of the engine. I also thought using that wasted exhaust heat and energy to spin a turbo was beneficial to improving cylinder filling. I also thought it if it took x amount of gallons of fuel to move a car y amount of miles and z amount of heat went out the exhaust, by lowering z I could go Y+ miles or use x less gallons. Guess I was wrong. http://en.wikipedia.org/wiki/First_law_of_thermodynamics Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.

Re: Turbocharging for economy [Re: jcc] #1085135 10/17/11 04:09 PM 10/17/11 04:09 PM
Joined: Jan 2003 Posts: 6,608 Indiana EV2DEMON The Camaro Kid
EV2DEMON The Camaro Kid Joined: Jan 2003 Posts: 6,608 Indiana	Quote: I guess the First law of thermodynmics does not apply to turbos. I always thought heat/energy sent out the exhaust was wasted and deducted from the total efficency of the engine. I also thought using that wasted exhaust heat and energy to spin a turbo was beneficial to improving cylinder filling. I also thought it if it took x amount of gallons of fuel to move a car y amount of miles and z amount of heat went out the exhaust, by lowering z I could go Y+ miles or use x less gallons. Guess I was wrong. http://en.wikipedia.org/wiki/First_law_of_thermodynamics That's not necessarily wrong, but, again, fails to account for the fact that while traveling at low-load highway speeds, a turbocharged IC gas engine is still making vacuum and not seeing any boost or associated benefits. So, the heat passing through the turbo and out the exhaust is still "wasted". Pretty sure that was covered on the first page though.

Re: Turbocharging for economy [Re: EV2DEMON] #1085136 10/17/11 05:22 PM 10/17/11 05:22 PM
Joined: Jun 2008 Posts: 10,847 Oakdale CT gdonovan I Live Here
gdonovan I Live Here Joined: Jun 2008 Posts: 10,847 Oakdale CT	I figure at this point people are just trolling since there is three pages of information on the subject that pretty much covers it.

Re: Turbocharging for economy [Re: EV2DEMON] #1085137 10/17/11 07:50 PM 10/17/11 07:50 PM
Joined: Dec 2003 Posts: 22,696 Bitopia J jcc If you can't dazzle em with diamonds..
jcc If you can't dazzle em with diamonds.. J Joined: Dec 2003 Posts: 22,696 Bitopia	Quote: a turbocharged IC gas engine is still making vacuum and not seeing any boost or associated benefits. And is that because the turbo is oversized for power instead of economy by choice? I'll reread the first page. Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.

Re: Turbocharging for economy [Re: jcc] #1085138 10/18/11 12:15 AM 10/18/11 12:15 AM
Joined: Jan 2005 Posts: 2,540 Milwaukee WI T TRENDZ master
TRENDZ master T Joined: Jan 2005 Posts: 2,540 Milwaukee WI	No, It's because if it was making boost it would be accellerating. If it's not making boost it's a parasitic loss. IF YOU ADD MORE AIR YOU NEED MORE FUEL. "use it 'till it breaks, replace as needed"

Re: Turbocharging for economy [Re: EV2DEMON] #1085139 10/18/11 11:20 AM 10/18/11 11:20 AM
Joined: Nov 2006 Posts: 2,255 IL furious70 top fuel
furious70 top fuel Joined: Nov 2006 Posts: 2,255 IL	Quote: Quote: I guess the First law of thermodynmics does not apply to turbos. I always thought heat/energy sent out the exhaust was wasted and deducted from the total efficency of the engine. I also thought using that wasted exhaust heat and energy to spin a turbo was beneficial to improving cylinder filling. I also thought it if it took x amount of gallons of fuel to move a car y amount of miles and z amount of heat went out the exhaust, by lowering z I could go Y+ miles or use x less gallons. Guess I was wrong. http://en.wikipedia.org/wiki/First_law_of_thermodynamics That's not necessarily wrong, but, again, fails to account for the fact that while traveling at low-load highway speeds, a turbocharged IC gas engine is still making vacuum and not seeing any boost or associated benefits. So, the heat passing through the turbo and out the exhaust is still "wasted". Pretty sure that was covered on the first page though. This point would apply more to an industrial or constant load application where you are always making boost. 70 Sport Fury 68 Charger 69 Coronet 72 RR

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