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Re: Super duper gas miledge 273/318 experiment !!! UPD
[Re: FuryUs]
#47727
03/21/08 10:19 AM
03/21/08 10:19 AM
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Joined: Feb 2003
Posts: 2,304
WI
RestoRick
top fuel
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top fuel
Joined: Feb 2003
Posts: 2,304
WI
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Quote:
Quote:
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This is interesting... Hughes Modified Magnum Intake
Scroll down and read the mileage increase claims..
Rick
Linky no worky
Go to http://www.hughesengines.com/ then magnum engine, induction. It's a little pricey...
Linky worky for me... 
Here's what they're competing against...($600ish)
If it does what they say it does it might be worth it to some...
Mopar Performance MPI manifold
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Re: Super duper gas miledge 273/318 experiment !!! UPD
[Re: GO_Fish]
#47728
03/24/08 07:59 PM
03/24/08 07:59 PM
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Joined: Jan 2003
Posts: 8,089
Sorrento, BC, Canada
4speeds4me
master
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master
Joined: Jan 2003
Posts: 8,089
Sorrento, BC, Canada
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Quote:
...but the engine vacumn picks up also because the engine is not laboring against the torque convertor. For long lights, kill the engine and restart.
I just press the clutch...
And correct me if I'm wrong, but was there EVER and OD auto from Ma Mopar that did NOT have a lock-up converter?
And lastly, if MPG is the greatest concern (I can't believe I'm asking this...I'm almost scared of the answer) what takes less power to turn? A 904 based auto or an 833?
2 Demons...no, not my kids! 
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Re: Super duper gas miledge 273/318 experiment !!! UPD
[Re: 4speeds4me]
#47729
03/24/08 10:28 PM
03/24/08 10:28 PM
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Joined: Jan 2005
Posts: 12,422
Kalispell Mt.
HotRodDave
OP
I Live Here
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OP
I Live Here
Joined: Jan 2005
Posts: 12,422
Kalispell Mt.
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Some 518s did not have lock up. A 4spd will be more efficent but the wife won't let me because she might need to drive it someday 
I am not causing global warming, I am just trying to hold off a impending Ice Age!
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Re: Super duper gas miledge 273/318 experiment !!! UPD
[Re: HotRodDave]
#47730
03/24/08 10:37 PM
03/24/08 10:37 PM
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Joined: Jan 2003
Posts: 8,089
Sorrento, BC, Canada
4speeds4me
master
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master
Joined: Jan 2003
Posts: 8,089
Sorrento, BC, Canada
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Time for a new wife, by the sounds of things. This one isn't willing to learn anything new... I was asking for my benefit anyways, as I looked at my 64 on Sunday, and oughta be dragging her home soon...  Quote:
I would like to get a custom speced cam but that is even more money.
And what kind of specs would you be looking for, Dave???
2 Demons...no, not my kids!
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Re: Super duper gas miledge 273/318 experiment !!! UPD
[Re: 4speeds4me]
#47731
03/25/08 07:36 AM
03/25/08 07:36 AM
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Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
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Quote:
Quote:
...but the engine vacumn picks up also because the engine is not laboring against the torque convertor. For long lights, kill the engine and restart.
I just press the clutch...
And correct me if I'm wrong, but was there EVER and OD auto from Ma Mopar that did NOT have a lock-up converter?
And lastly, if MPG is the greatest concern (I can't believe I'm asking this...I'm almost scared of the answer) what takes less power to turn? A 904 based auto or an 833?
'91-92 A518's were non-lockup. all A500's were lockup, and all newer 518/46RH/46RE are lockup.
1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
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Re: Super duper gas miledge 273/318 experiment !!! UPD
[Re: 4speeds4me]
#47732
03/25/08 10:21 AM
03/25/08 10:21 AM
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Joined: Jan 2005
Posts: 12,422
Kalispell Mt.
HotRodDave
OP
I Live Here
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OP
I Live Here
Joined: Jan 2005
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Kalispell Mt.
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I think for a custom cam I would want about 175@.050 with as much lift as they can possibly get from a .904 diameter lifter and get a 110 or mabey even 112 LSA to keep overlap next to none. Imagine a baby comp MM lobe. Remember that at short durations the flat tappet can lift the valves faster than a roller. I would probably try to get as high of a rocker ratio as I could to get lift open real good so it could make a little bit of hp. The extra hp would be there if needed but not costing you anything when you don't need it. I think the overlap and late closeing intake are the 2 biggest things for desighning an MPG cam. The overlap costs efficency when some of the intake charge goes out the exhaust (obviously wasted and produces no power)and some of the exhaust goes in the intake track(reversion)and dilutes the next charge comeing back in causing it to burn slower. If you look at some of the newer engines they are going this direction and still makeing real nice hp. An example is the new Hemis with right around 200 degrees duration. Also of less importance but still there is the ex opening point, the charge is still burning when it opens so opening it a couple degrees later gives it a couple more degrees to push on the crank. I think with heads really desighned to get flowing at low lifts like magnums with 33 degree seats and deshrouded chambers around the 2.02 valves you would be suprised at the hp it could make also. It would not be a beast so to speak but it would be way better than a Geo metro 3cyl for sure. I think a combo like that could even lower the tq in the rpm range even more and alow for a higher gear ratio also. BTW according to the waller calculator I had the cuda doing 139 mph the other day 
I am not causing global warming, I am just trying to hold off a impending Ice Age!
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Re: Super duper gas miledge 273/318 experiment !!! UPD
[Re: HotRodDave]
#47733
03/27/08 04:18 PM
03/27/08 04:18 PM
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Joined: Jan 2003
Posts: 4,558
Montana
FuryUs
master
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master
Joined: Jan 2003
Posts: 4,558
Montana
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Quote:
BTW according to the waller calculator I had the cuda doing 139 mph the other day
What does this mean?
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Re: Super duper gas miledge 273/318 experiment !!! UPD
[Re: FuryUs]
#47734
03/27/08 07:05 PM
03/27/08 07:05 PM
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Joined: Jan 2005
Posts: 12,422
Kalispell Mt.
HotRodDave
OP
I Live Here
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OP
I Live Here
Joined: Jan 2005
Posts: 12,422
Kalispell Mt.
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I put the RPM the tire hight and gear ratio into the speed calculator and it said I was going that fast when I was "not-raceing" a saturn aura XR the other day. I only looked at the tach not the speedo until I had slowed down a bunch, so when I got home I checked to see how fast it was.
I am not causing global warming, I am just trying to hold off a impending Ice Age!
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Re: Super duper gas miledge 273/318 experiment !!! UPD
[Re: HotRodDave]
#47735
03/30/08 04:26 AM
03/30/08 04:26 AM
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Joined: Jan 2003
Posts: 8,089
Sorrento, BC, Canada
4speeds4me
master
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master
Joined: Jan 2003
Posts: 8,089
Sorrento, BC, Canada
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Wow...did you really mean 175º @ .050"? Looking at Comps lobes this is about all that stands out...Lobe# 3100 230º adv. 178º @ .050. .405" w/1.5's, .432" w 1.6's, and .459" w/1.7's. I'd prefer to see the 1.6 or 1.7 number with 1.5's, I think, but this was about the only lobe they have with less than 200º @ .050. Most are 230+... http://www.compcams.com/Technical/Search/CamDetails.asp?PartNumber=20-416-3How does this look for an "off-the-shelf" flat tappet unit?
2 Demons...no, not my kids!
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Re: Super duper gas miledge 273/318 experiment !!! UPD
[Re: HotRodDave]
#47736
03/30/08 08:06 AM
03/30/08 08:06 AM
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Joined: Jan 2003
Posts: 4,558
Montana
FuryUs
master
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master
Joined: Jan 2003
Posts: 4,558
Montana
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Quote:
I put the RPM the tire hight and gear ratio into the speed calculator and it said I was going that fast when I was "not-raceing" a saturn aura XR the other day. I only looked at the tach not the speedo until I had slowed down a bunch, so when I got home I checked to see how fast it was.
Gotcha! Good thing you weren't racing--that might waste gas!
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Re: Super duper gas miledge 273/318 experiment !!! UPD
[Re: BigTerry]
#47737
03/30/08 08:11 AM
03/30/08 08:11 AM
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Joined: Jan 2003
Posts: 4,558
Montana
FuryUs
master
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master
Joined: Jan 2003
Posts: 4,558
Montana
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Quote:
the one thing that been eaten at me was the concept that fi was suppose to give better performance and fuel mileage over a carb what gives?? I would love to get alittle more fuel mileage out of my 99 p/u 318 auto. What about installing taller tires wouldn't that help fuel mileage?
The problem is peak fuel efficiency isn't always the cleanest burn. The tailpipe has to put out limited amounts of... whatever comes out the tail pipe, and leaning it out for best mileage can jack that up. Also, it seems to me that the pre-magnum TBI motors got better mileage, but the lean condition led to cracked heads over time.
Taller tires should help with cruise mileage if the combo is right, but it'll affect acceleration. Skinnier tires will help with rolling resistance.
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Re: Super duper gas miledge 273/318 experiment !!! UPD
[Re: FuryUs]
#47738
03/30/08 08:34 AM
03/30/08 08:34 AM
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Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
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Quote:
Quote:
the one thing that been eaten at me was the concept that fi was suppose to give better performance and fuel mileage over a carb what gives?? I would love to get alittle more fuel mileage out of my 99 p/u 318 auto. What about installing taller tires wouldn't that help fuel mileage?
The problem is peak fuel efficiency isn't always the cleanest burn. The tailpipe has to put out limited amounts of... whatever comes out the tail pipe, and leaning it out for best mileage can jack that up. Also, it seems to me that the pre-magnum TBI motors got better mileage, but the lean condition led to cracked heads over time.
Taller tires should help with cruise mileage if the combo is right, but it'll affect acceleration. Skinnier tires will help with rolling resistance.
tuning for emissions (specifically lower NOx emissions) leads to fuel economy compromises
taller tires might be a wash, because if they have worse rolling resistance, or if they raise the truck up higher, and cause more aerodynamic drag, you'll need slightly more power to maintain the same speed, offsetting dropping the engine RPM.
also, look at the HP/tq ratings of a magnum 318 (230 hp/300 tq) vs. say the 318 out of my 5th ave that got 22-25 highway mpg (140hp, 265 tq)....more power requires more fuel....
1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
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Re: Super duper gas miledge 273/318 experiment !!! UPD
[Re: 4speeds4me]
#47739
03/30/08 08:46 AM
03/30/08 08:46 AM
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Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
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Quote:
Wow...did you really mean 175º @ .050"? Looking at Comps lobes this is about all that stands out...Lobe# 3100 230º adv. 178º @ .050.
.405" w/1.5's, .432" w 1.6's, and .459" w/1.7's. I'd prefer to see the 1.6 or 1.7 number with 1.5's, I think, but this was about the only lobe they have with less than 200º @ .050. Most are 230+...
http://www.compcams.com/Technical/Search/CamDetails.asp?PartNumber=20-416-3
How does this look for an "off-the-shelf" flat tappet unit?
too much overlap...that has 45 degrees overlap. I'd look at a voodoo 60400 (250/256, 208/213@.50, .454 lift, 112 LSA. that has only 29 degrees overlap (compared to about 16 degrees for a stock flat tappet 318, or ~26 degrees for a stock flat tappet 360 cam)....
1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
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Re: Super duper gas miledge 273/318 experiment !!! UPD
[Re: patrick]
#47740
03/30/08 03:17 PM
03/30/08 03:17 PM
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Joined: Jan 2003
Posts: 8,089
Sorrento, BC, Canada
4speeds4me
master
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master
Joined: Jan 2003
Posts: 8,089
Sorrento, BC, Canada
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So, if I could get that cam on a 116º LSA, what would it do to my overlap? Most of the times when I'm doing this stuff, I'll find a cam that has a close spec. Then I get a look at my available lobes from my cam regrinder, and tell him what lobe and LSA I'd like. He finds a core that'll take it, and 75-100 bucks later I have a cam ready to go to my specs.
2 Demons...no, not my kids!
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Re: Super duper MPG 273/318 experiment ! NUMBERS!!!!!!!
[Re: Dakota_Don]
#47742
03/30/08 11:09 PM
03/30/08 11:09 PM
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Joined: Jan 2003
Posts: 8,089
Sorrento, BC, Canada
4speeds4me
master
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master
Joined: Jan 2003
Posts: 8,089
Sorrento, BC, Canada
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Off the top of my head? 30 over 318 with KB167 pistons. 273/2-bbl solid cam. 302 casting heads with stock valve diameters and the sharp edges smoothed off. Factory 4bbl intake with TQ, IIRC, and TTI headers because the next plan is a 400+ inch SB. Best numbers he's posted so far if memory serves are 23 city and 29 HWY...maybe 23 combination city/hwy, and 29 hwy...
2 Demons...no, not my kids!
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Re: Super duper MPG 273/318 experiment ! NUMBERS!!!!!
[Re: 4speeds4me]
#47743
03/31/08 08:02 AM
03/31/08 08:02 AM
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Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
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easiest way to determine overlap:
take the adv. intake and exhaust duration. add them.
take the sum, divide by 4.
subtract the LSA from that
multiply by 2.
for example, a comp XE250H is 250/260 adv. 206/212@.050, on a 110 LSA.
so 250+260=510. 510/4=127.5 127.5-110=17.5 17.5*2=35, the cam has 35 degrees of overlap. widen the LSA to 116, and you get 127.5-116=11.5 11.5*2=23, so the cam would have 23 degrees of overlap.
BTW, the overlap numbers I was quoting for the stock cams I was assuming a 114 LSA, since I could find advertised durations for them, but not LSA, and 114 seems reasonable...
Last edited by patrick; 03/31/08 08:04 AM.
1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
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Re: Super duper MPG 273/318 experiment ! NUMBERS!!!!!!!
[Re: 4speeds4me]
#47744
03/31/08 07:08 PM
03/31/08 07:08 PM
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Joined: Jan 2003
Posts: 6,816
Alton, IL
Dakota_Don
master
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master
Joined: Jan 2003
Posts: 6,816
Alton, IL
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23 and 29, with a 318...... for real  so what if i took a 68 318, added magnum stock heads.. decent exh manifold (360 or headers) and some HYD camshaft and good Ignition system with an OD trans then it should get that or close to it.. what intake? cast iron w/ a mid 70s BBD 2 barrel or alu w/ a TQ 4 barrel?
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Re: Super duper MPG 273/318 experiment ! NUMBERS!!!!!!!
[Re: Dakota_Don]
#47745
04/04/08 07:00 PM
04/04/08 07:00 PM
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Joined: Jan 2005
Posts: 12,422
Kalispell Mt.
HotRodDave
OP
I Live Here
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OP
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Kalispell Mt.
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Some of you need to go back and read the entire thread, many of the questions being asked have been asked and answered a couple times.
4speeds has it right on, except I have a brand new LD4b intake. I also have a 190 tstat and electric fan a LU 904 tranny with low 1st and 2nd gears. 2.76 gears. Manual steering no ac no power brakes. Light weight aftermarket scat I beam rods. Electronic ign. I get about 5 mpg better now than the when I bought it with the bone stock #s match 318 2bbl. I have to use premium gas but it is still cheaper to operate than before with a nice bonus of more HP and TQ derived from burning more of the fuel when it counts, in the engine not the exhaust.
I think the mag heads would be about the same mpg with a little more WOT HP.
I am not causing global warming, I am just trying to hold off a impending Ice Age!
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Re: Super duper MPG 273/318 experiment ! NUMBERS!!!!!!!
[Re: HotRodDave]
#47746
04/05/08 10:57 PM
04/05/08 10:57 PM
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Joined: Dec 2005
Posts: 1,160
Cruising!
QuickDodge
super stock
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super stock
Joined: Dec 2005
Posts: 1,160
Cruising!
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How does one tune for maximum mileage? I saw on a previous page that Hotroddave40 used the smallest jets and largest metering rods he could find. I have a different carb, so this advice may or may not work.
I've heard in the past that an excessively lean mixture will burn hotter, possibly causing overheating and/or burnt valves. So my question is, How can one know when the engine is tuned as lean as possible without doing any damage to the engine? Ideally, I'd like to know how to reach this point without using an oxygen sensor to measure the air/fuel ratio.
Last edited by QuickDodge; 04/05/08 11:00 PM.
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