67rsss

iTrader: (4)

While this is not a long term average, we have already seen 26.6mpg in our LS1/T56 swap into a first gen camaro. While we are taking it easy on the car right now, this really exceeded our expectations. We had hoped to get at least 18mpg!!!

What kinda milage are you guys getting? Please include the engine/trans and what vehicle its in. Driving style may help....

Rantheman

I'm also curious on this subject

Also 67rss was it highway miles flat hils or what

67rsss

iTrader: (4)

Dude, this is MN, its all flat! 100 or so miles where in 5th or 6th on the highway, the rest about town. Only a few blasts on the throttle to get a feel for it, but we are trying to be patient and break the clutch in right. We also don't want to make any hard launches, as the 10 bolt open diff will definatley give up the ghost if we do!

fouz65

my scan gauge 2 says im getting around 22-24 "avg". but i have changed my tires since my dyno tune and he changed the pcm to 205 tires (what i had then). im running 255 ATM and going to 275 soon. im taking it back to him after i get the 275's. bottom line is the scan gauge 2 is off right now. and im running 3.9 gears so that hurts me a little. maybe with the 275's and the pcm changed to match the tires it will be better.
and i live in a hilly area.

bczee

iTrader: (12)

I did about 350 miles trip last weekend (about 280 was freeway) and got 23+ doing 70-80 most of the time., Stock LS1 with T56. 4:11 rear and 275x40x17 tires. Engine has no smog, air or cats, duel 2 1/2 with flowmasters.

a10beav

I'm getting about 17 in town and 27 on the highway. LS2, T56 and Ford-9 with 3:50's. It's a street legal exhaust as well.

Oscar Will

I put a set of 3.25 gears in mine as we are preparing to do a Route 66 cross country jaunt in the near future. With that gearset I did a trip this weekend and netted 27.5 mpg.............and that was at 75-80 mph on the freeway. Try THAT with anything else that will run a mid 13 second quarter mile!!!

LS1-IROC

iTrader: (4)

I just got 29mpg on a recent trip stock LS1/T56 in a light thirdgen with 3.42 gears.

IOwnCalculus

I've yet to do better than 14 highway, which is about what my carbed 350 got with the 700R4 behind it. Still haven't beaten my best-ever mileage, which was the result of a heavy rainstorm and bald tires - a 130 mile trip I usually do at 75-85 was now a 55-60MPH affair, and that was long before the LS1 swap.

It did improve "city" mileage (I say that because it includes a good bit of in-town freeway) considerably, though. Went from 10 to 13-14.

My LS1 has also tied my old 350 for worst mileage on a tank without having a major fueling problem...the first long trip I took it on, I couldn't keep my foot out of it and was solidly in the single digits for mileage.

The problem is far more my right foot than anything else, though

John B

iTrader: (10)

With the LS1 motor, B1 cam and 4.10's I would get mid 20's on the highway. With the LS7 it's about the same!

digitalsolo

iTrader: (24)

15-16 mpg averaging city/highway.

cammed 5.3L w/ 3800 stalled 4L60e and 4.10 gears.

Still working on the tune though, I think there is another 3-4 mpg to be had.

LS1GMCTruck

iTrader: (2)

Un-fuc-ing believable! What a great all-around package, huh? John, in the 1/4 mile...what gear do you go through the traps in? And at what RPM? Any idea?

Stu Cool

iTrader: (13)

Trips I have measured I get about 25 on the highway. 70 mph, A/C and cruise control on. Details are in my sig, my tires are almost 29" tall. I plan on a drivability tune pretty soon, after that I may do better.

Pat

89 formula350

iTrader: (8)

sounds right. I was hopping I could get up to 31 mpg hwy in my thirdgen ls1. it's a formula so it should be possiable

G-Body

iTrader: (4)

My normal city driving nets me 14-16 and I don`t exactly baby the car, actually I think most rentals are driven easier than my car.

I usually get 18-19 on the highway ~70mph. But my best ever was 22mpg on the highway, I was slowed down to 55-65 because I was flat-towing a suburban .

My dragstrip fuel mileage is ~13mpg, I filled the car up a couple miles from the strip, made 30 passes and topped the tank off at the same station on the way home. I couldn`t believe I averaged 13mpg between the ~15 miles on the street and 30 passes.

My numbers might be artificially low though, I just discovered a couple weeks ago that my mechanical odometer on my electric speedo neglects to register the mileage sometimes. It registered a little over 3 miles on the way to work (its a 25 mile drive to work) So it now makes me wonder how many miles the odometer has missed.

99c5vert

I only measured it once... on a trip that took me through skyline drive and down I 64 to Williamsburg. I averaged 26.5 MPG. I was playing a little in the twisties, and doing about 75 on the highway.

As you can see, my car isn't exactly aerodynamic.

Cam72aro

iTrader: (28)

I have calculated 22-24 on the highway with heads and cam. Around town it will get 17-18. This is not getting on it much either.

OldSchoolFormula

I have seen just a hair under 25MPG freeway cruising in my car. My daily commute seems to net me around 19MPG average. I just had my absolute worst tank EVER this past tank, it was only 14.8MPG. I think it was because I have been letting it idle for extended periods of time playing with the A/C and such. Hopefully this tank gets back to normal. No codes.

72ChevelleConv.LS1

iTrader: (5)

THe chevelle dosn't have a odometer but I am guessing around 20-23 hwy. the vette is a 98 and heads/cam/intake and 3:15 auto trans and the I have averaged 26 MPG.

90LS1TOY

iTrader: (38)

In my cammed ls1/t56 with 4:10s at about 85 on a 1200 mile trip avg. 21 on the interstate in my toyota truck.