LS MPG in swaps...

mrvette

Phantom of the Opera
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Mar 24, 2008
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Into older vettes, also the trans and final ratio in your ride, and of course what car.....

:p
 
68 vette convertible, 6.0 LQ9, stock with mild tune, Richmond 6 speed (0.76 OD), 3.08 rear. Low 20s combined, best of 26mpg hiway.
 
With a 6spd you can probably get 28mpg highway...... I used to have a 99 Z28 and it got 26 highway mpg with a auto tranny...... 6 spd drops the rom even lower...... Right now with my LS2 C6 I can get 30mpg highway if I keep my foot off the pedal.....but that's really trying hard not to push the pedal.....

I would think that 25mpg in a c3 with 3.55 gears is very realistic.

City driving: anywhere from 14-20 mpg...... Depending on how heavy your foot is......
 
I am getting 16-17 mpg. LS1 with cam and 2004R 3:08 gears. 1800 rpm at 60 mph. Should get better longer it runs and more tuning. Can't seem to keep my foot out of it and really don't have any long highway miles yet.
 
16-17 is low.... As you say, on longer trips you can expect mpg to go up a bit...

City/highway mix I think 20mpg average is not unrealistic....

What's funny is that this mpg is actually better than my '93 Fox 2.3L mustang.... Only getting 25mpg highway with it, best ever was 27 but that was snail speed.....
 
Well, thanks guys, I getting damn nearly the same MPG as all you guys, with my 336 gear, and 200 4r, and 350 roller engine...

so I suppose not much is left on the table for doing the LS swap, as the current engine runs fine....not worth the hassle in other words.....

oh well.....:eek::surrender::thumbs:
 
I was debating going with an Ls3 or the new ZZ383 (450/450) for a long time. I know that the Ls engines are great but from talking with a few guys who've done the swap c/w tune and reading the forums it seems that mileage may be up 1 or 2 mpg. The big increase came from adding a 5 or 6 sp. Some of you may know MotorHead, he's getting 24 - 26 mpg with his 427 sb, TKO 5 sp and a 825 Drag Race Demon carb.
 
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So I don't feel so bad on the MPG gig.....my '72 got 24 up and down I 95 back in winter '97.....336 rear and muncie stick shift....L98 injection on a dead stock L48 engine.....obviously no overdrive....

so IF I had an o/drive maybe it would have been slightly better....
I was cruising 80 mph at ~4k rpm.....

but that was back in '97 today with all the ethanol, and shit, but having same engine size but upgraded.....355 L98 injected roller engine, and 200 4r seems I should be able to do about 28 or so.....

and what gets ME, is for all of what I hear, most guys with new vettes get about 26-28 on the freeways, ~80mph steady on pull....and honestly I am surprised, I would have thought closer to 32 mph anyway.....

I thinking of messing with the injector firing order on an interrupt basis at any speed above 60 mph......:smash:
 
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