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Re: Fuel mileage improvement success! [Re: Guitar Jones] #3094188
11/14/22 04:16 PM
11/14/22 04:16 PM
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Bend,OR USA
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I think we all need to remember that it takes a certain amount of energy to move the mass when operating any vehicle, car, truck, boat or airplanes.
The faster you go the more fuel it will use and the quicker it will get to where you want to go shruggy work
I remember talking to some SCTA (Southern CA Timing Assoc.) land speed racers at El Mirage on how fast they could make cars stock street go back in the mid 1970s, the replies were anyone can go 125 MPH, some can go 150 MPH but once you get above a certain speed, usually 150 MPH, you have to double the HP to go 175 MPH in the same car with no other changes shock work
I had that example made to me while flying my 1960 Piper Comanche 250 home too SO CA from the Tacoma ,WA area after visiting our grandkids. I was flying at 11,500 above a solid cloud cover, the outside air temp was right at +5 F, I had the airplane trim out to fly straight and level at 2400 RPM with the mixture set at 50 F rich below peak EGT, the ride was very smooth and basically boring so I thought I will try slowing the prop RPM down to try and save some fuel, I use the prop controller to slow it down and then retrim and reset the mixture for that RPM and that stupid dang airplane went from 148 knots ground speed up to 162 knots shock I didn't believe that at all so I redid that test twice in the next 20 minutes, it repeated boogie Got their faster and saved fuel, went from 10.0 GPH to 9.6 GPH at 13 knots quicker ground speed up
I am not a weather guru or know anyone who is but I ended up thinking that the colder denser air at that altitude that day was pushed more efficiently by my prop at 2300 RPM versus 2400 RPM shruggy
Testing paid OFF up
Your right foot determines the fuel mileage, a vacuum gauge can help you get the best mileage on long trips by using the lightest pedal pressure you can to maintain the speed you want to go that day on hat trip up scope

Last edited by Cab_Burge; 11/14/22 05:07 PM.

Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Fuel mileage improvement success! [Re: Cab_Burge] #3094233
11/14/22 08:34 PM
11/14/22 08:34 PM
Joined: Dec 2009
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in a cattle trailer down by th...
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Guitar Jones Offline OP
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in a cattle trailer down by th...
I wasn't trying to get a maximum mileage figure just something that would be representative of what it would get driving it like I would normally, well except for not stabbing the throttle a couple times laugh2


I raise chickens, so I am literally a chicken tender.

The Scamp is sold, now just two old trucks and one newer one.
'92 D250 Club Cab CTD, 47RH conversion, pump tweaks, injectors, rear disc and hydroboost conversion.
'74 W200 Crew Cab 360, NV4500, D44, D60 and NP205 divorced transfer case.
2019 1500 Long Horn Crew Cab 4WD, 5.7 Hemi.
Re: Fuel mileage improvement success! [Re: HotRodDave] #3094240
11/14/22 09:15 PM
11/14/22 09:15 PM
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Plymouth, MI
Blusmbl Offline
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Originally Posted by HotRodDave

EGR does not help MPG, it is strictly there for emissions. It actually lowers MPG and is the reason manufacturers are going away from it.


On a gasoline engine this isn’t true, EGR helps with milage due to the reduction in pumping work and it moves the timing needed to make peak torque for any given speed/load. The engine bsfc will improve with modest amounts of EGR in the cruise range.

The vehicles that don’t have EGR now usually have variable cam timing on both the intake and exhaust, and they accomplish EGR by moving the cams in relation to each other.


'18 Ford Raptor, random motorcycles, 1968 Plymouth Fury III - 11.37 @ 118
Re: Fuel mileage improvement success! [Re: Cab_Burge] #3094241
11/14/22 09:16 PM
11/14/22 09:16 PM
Joined: Jan 2003
Posts: 2,498
541 slobovia
A990 Online content
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I've found that MPG gains are always improved most by dropping RPM.
I guess that Piper had a flat 6? Thats a 300 combustion cycles per minute drop in fuel use. Having pitch control on the prop was a huge advantage, since you could adjust the load.

I found MPG in an adjustable PCV valve. My 99 Dakota with the 5.9 dropped more the 100 RPM at idle, and that helped city mpg quite a bit.
The OEM pcv design is inaccurate and inconsistent. I put one on my 73 Ford and the adjustment range let me set the idle at 550 to 600, and it gained around town as well.

I wondered how a Magnum would do with a well programmed 8 speed, so that cruise RPM could be held around 1800 or so

Re: Fuel mileage improvement success! [Re: Blusmbl] #3094246
11/14/22 09:35 PM
11/14/22 09:35 PM
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Kalispell Mt.
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Originally Posted by Blusmbl
Originally Posted by HotRodDave

EGR does not help MPG, it is strictly there for emissions. It actually lowers MPG and is the reason manufacturers are going away from it.


On a gasoline engine this isn’t true, EGR helps with milage due to the reduction in pumping work and it moves the timing needed to make peak torque for any given speed/load. The engine bsfc will improve with modest amounts of EGR in the cruise range.

The vehicles that don’t have EGR now usually have variable cam timing on both the intake and exhaust, and they accomplish EGR by moving the cams in relation to each other.



Leaning out the mixture will do all the same things. Also running a leaner mix does not decrease the statistical probability of a fuel molecule finding and reacting with an oxygen molecule in a timely fashion but a lean mix don't get along with a cat used for reacting remaining carbon in the exhaust stream with remaining oxygen. It also does not reduce peak temp as much as EGR that causes NOX, it is the more emissions friendly way but not quite as efficient MPG wise as leaning out the mixture. Also new hemis don't have EGR and don't change the intake and exhaust cam separately, they merely retard the whole cam to reduce cylinder pressure under certain conditions. I have tested many vehicles with and without the EGR hooked up and every. single. one. got worse MPG with it working including my current 92 dakota with a 318.


I am not causing global warming, I am just trying to hold off a impending Ice Age!



Re: Fuel mileage improvement success! [Re: Guitar Jones] #3094283
11/15/22 07:05 AM
11/15/22 07:05 AM
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USA
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360view Offline
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Originally Posted by Guitar Jones
The engine doesn't make a ton of vacuum, even though the cam is mild it has a 108° LSA, 60° of overlap IIRC.


With a camshaft of those specs,
at low rpm and part throttle, the engine is probably creating at least 5% “internal EGR.”

If the exhaust valve stays partially open past top dead center when intake manifold pressure is low, it naturally pulls in exhaust gas.

Lean air to fuel ratios improve fuel economy by raising raising intake manifold pressure.

Exhaust gas recirculation improves fuel economy by raising manifold pressure
- but too much EGR can cause ignition missfires to increase.
A single sparkplug with low swirl cylinder head design will begin ignition missfire earlier than dual sparkplugs with high swirl heads.

Since this engine has a carb it would be relatively easy to leak some air air around the carb to lean it out - airplane style.

Re: Fuel mileage improvement success! [Re: 360view] #3094311
11/15/22 09:58 AM
11/15/22 09:58 AM
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PINE VALLEY
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Originally Posted by 360view


Since this engine has a carb it would be relatively easy to leak some air air around the carb to lean it out - airplane style.

My 75 B300 camper van (360 2BBL) would run way rich at 9,000', so I added a 3/8" bleed line to the carb base and a valve where I could reach it. Just left it open whenever in Utah.

My Geo Metro TBI 3 banger runs poorly without the EGR functioning perfectly, and get 52mpg highway when it is.

Last edited by Ray S; 11/15/22 09:58 AM.
Re: Fuel mileage improvement success! [Re: Ray S] #3094388
11/15/22 01:41 PM
11/15/22 01:41 PM
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Kalispell Mt.
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Originally Posted by Ray S
Originally Posted by 360view


Since this engine has a carb it would be relatively easy to leak some air air around the carb to lean it out - airplane style.

My 75 B300 camper van (360 2BBL) would run way rich at 9,000', so I added a 3/8" bleed line to the carb base and a valve where I could reach it. Just left it open whenever in Utah.

My Geo Metro TBI 3 banger runs poorly without the EGR functioning perfectly, and get 52mpg highway when it is.


I blocked the EGR on my dads 97 metro 5 speed he bought brand new and it did better. It would do right aroun 50 MPG on the highway with and about 52 or 52 without it under identicle conditions but it did make the CEL come on with an insufficient EGR flow code so I took my block off plate and made a tiny hole so it could still get just enough flow to keep the light off and it settled right down around 50 and 51 mpg.

I been making a spacer for my 92 dakota to block off the exhaust and instead open up to introduce fresh air when the valve opens, I expect the O2 sensor will just "fix" the AF ratio but figure it is worth a try in my free time.


I am not causing global warming, I am just trying to hold off a impending Ice Age!



Re: Fuel mileage improvement success! [Re: A990] #3094436
11/15/22 04:42 PM
11/15/22 04:42 PM
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Atlanta, GA
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Originally Posted by A990
I've found that MPG gains are always improved most by dropping RPM.
I guess that Piper had a flat 6? Thats a 300 combustion cycles per minute drop in fuel use. Having pitch control on the prop was a huge advantage, since you could adjust the load.

I found MPG in an adjustable PCV valve. My 99 Dakota with the 5.9 dropped more the 100 RPM at idle, and that helped city mpg quite a bit.
The OEM pcv design is inaccurate and inconsistent. I put one on my 73 Ford and the adjustment range let me set the idle at 550 to 600, and it gained around town as well.

I wondered how a Magnum would do with a well programmed 8 speed, so that cruise RPM could be held around 1800 or so



How much fuel mileage gain did you find?

Curious how that would work since the IAC valve would adjust for different idle speed wouldn't it?

Re: Fuel mileage improvement success! [Re: mgoblue9798] #3094442
11/15/22 05:19 PM
11/15/22 05:19 PM
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All driving about 2 or 3 mpg.
The IAC does compensate, but I guess the PCV design is very consistent across all throttle positions and loads. The adaptives in the computer respond with more accurate fuel/timing profiles.
It's just a swag on my part.
The idle drop takes several miles (or startups) to occur though. But that's just with a computer reset.

Re: Fuel mileage improvement success! [Re: HotRodDave] #3094463
11/15/22 06:55 PM
11/15/22 06:55 PM
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Originally Posted by HotRodDave


I blocked the EGR on my dads 97 metro 5 speed he bought brand new and it did better. It would do right aroun 50 MPG on the highway with and about 52 or 52 without it under identicle conditions but it did make the CEL come on with an insufficient EGR flow code so I took my block off plate and made a tiny hole so it could still get just enough flow to keep the light off and it settled right down around 50 and 51 mpg.

Consensus on GMF is that EGR is best if all else is stock
https://geometroforum.com/viewtopic.php?p=766586#p766586
The ECU map is fixed and programmed for it.

https://geometroforum.com/memberlist.php?mode=viewprofile&u=9543

Ha, and I just saw my old post on carbon cleaners https://geometroforum.com/viewtopic.php?p=706381#p706381

Re: Fuel mileage improvement success! [Re: mgoblue9798] #3094464
11/15/22 06:58 PM
11/15/22 06:58 PM
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Originally Posted by mgoblue9798


Curious how that would work since the IAC valve would adjust for different idle speed wouldn't it?

I have considered adding a new IAC to the 71 413-1 (Holley 4150) so I could go leaner with a dash switch, but I'm not sure what size to get, or what is the biggest flow out there. One can always reduce the flow if too much.

Re: Fuel mileage improvement success! [Re: Ray S] #3094586
11/16/22 07:49 AM
11/16/22 07:49 AM
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You can reduce EGR flow by relocating the EGR tapping point in the exhaust farther toward the tailpipe.

The longer pipe carrying this exhaust gas back to the intake manifold will also act as a gas cooling “radiator”.

Cooled EGR will raise intake manifold pressure, but WITHOUT increasing combustion chamber tendency to knock/ ping/ detonate.

I have thought about doing this using Cunifer metal tubing and designing all curves with long radius elbows to make periodic carbon deposit “rod outs” cleaning easier.

If you scientifically care about such things,
cooled EGR reduces NOx even more than hot EGR.
That is why OEM’s put those high $ EGR radiators on that clog up so bad.

I first saw a “water scrubber” on coal mining “scoops” and “Ramcars” with diesel engines in the 1970s.
These water scrubbers are the ultimate in exhaust gas cleaning but require clean out of “black gunk” and water refill at least every two days.
I have also pondering building a 2x2x2 foot water scrubber in the bed of my pickup to super clean and super cool the exhaust gas for EGR.

Re: Fuel mileage improvement success! [Re: Ray S] #3094629
11/16/22 11:32 AM
11/16/22 11:32 AM
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Ray there are "stand alone" stepper motors/ iac valves that can be installed using a vacuum line rather than trying to attach directly to the carb. Maybe a manual rheostat could be used to control the opening at part throttle cruise? With your computer knowledge though I am sure you would fashion something a little less crude.

Re: Fuel mileage improvement success! [Re: mgoblue9798] #3094646
11/16/22 12:10 PM
11/16/22 12:10 PM
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Ray S Offline
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Originally Posted by mgoblue9798
Ray there are "stand alone" stepper motors/ iac valves that can be installed using a vacuum line rather than trying to attach directly to the carb. Maybe a manual rheostat could be used to control the opening at part throttle cruise? With your computer knowledge though I am sure you would fashion something a little less crude.

Yeah I was thinking a new port under the carb - I have a 1" spacer that I could drill and tap.
A stepper solenoid would be cool but I don't have the Pi touchscreen going yet, too many other paying projects.

Re: Fuel mileage improvement success! [Re: 360view] #3094682
11/16/22 01:08 PM
11/16/22 01:08 PM
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Originally Posted by 360view
You can reduce EGR flow by relocating the EGR tapping point in the exhaust farther toward the tailpipe.

The longer pipe carrying this exhaust gas back to the intake manifold will also act as a gas cooling “radiator”.

Cooled EGR will raise intake manifold pressure, but WITHOUT increasing combustion chamber tendency to knock/ ping/ detonate.

I have thought about doing this using Cunifer metal tubing and designing all curves with long radius elbows to make periodic carbon deposit “rod outs” cleaning easier.

If you scientifically care about such things,
cooled EGR reduces NOx even more than hot EGR.
That is why OEM’s put those high $ EGR radiators on that clog up so bad.

I first saw a “water scrubber” on coal mining “scoops” and “Ramcars” with diesel engines in the 1970s.
These water scrubbers are the ultimate in exhaust gas cleaning but require clean out of “black gunk” and water refill at least every two days.
I have also pondering building a 2x2x2 foot water scrubber in the bed of my pickup to super clean and super cool the exhaust gas for EGR.


I've been saying for years that the EGR should be picked up after the cat to keep from picking up all the raw carbon that gets deposited in the intake tract. Also it would reduce or eliminate the need for EGR coolers that are so troublesome.


I am not causing global warming, I am just trying to hold off a impending Ice Age!



Re: Fuel mileage improvement success! [Re: mgoblue9798] #3094685
11/16/22 01:11 PM
11/16/22 01:11 PM
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Originally Posted by mgoblue9798
Ray there are "stand alone" stepper motors/ iac valves that can be installed using a vacuum line rather than trying to attach directly to the carb. Maybe a manual rheostat could be used to control the opening at part throttle cruise? With your computer knowledge though I am sure you would fashion something a little less crude.


How about a vacuum switch to open it? This would only allow it to open under high vacuum that happens when the engine is fully warmed up and under decel conditions when it don't need fuel at all. Ideally an adjustable one where cut on and off are both adjustable. This is sort of how the bypass thingy on the back of some thermoquads was sposed to work.


I am not causing global warming, I am just trying to hold off a impending Ice Age!



Re: Fuel mileage improvement success! [Re: HotRodDave] #3094696
11/16/22 01:27 PM
11/16/22 01:27 PM
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Originally Posted by HotRodDave
Originally Posted by mgoblue9798
Ray there are "stand alone" stepper motors/ iac valves that can be installed using a vacuum line rather than trying to attach directly to the carb. Maybe a manual rheostat could be used to control the opening at part throttle cruise? With your computer knowledge though I am sure you would fashion something a little less crude.


How about a vacuum switch to open it? This would only allow it to open under high vacuum that happens when the engine is fully warmed up and under decel conditions when it don't need fuel at all. Ideally an adjustable one where cut on and off are both adjustable. This is sort of how the bypass thingy on the back of some thermoquads was sposed to work.

Good idea, but the problem I've had at 9,000' is that it always needs leaning, which is what the later T-quads had built in - Holley never did.

My 318 in the old Chinook wouldn't even start at Brianhead unless I held the choke wide open.
I have also considered manual choke which my 68 F100 had. The Holley electric "automatic" is time-based electric heat rather than eng temp based.

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