Gas mileage: 100 hwy / 100 city 15.1
Horsepower/Torque: 275 hp (crank) 325 torque
Gearing: 2.73
Transmission: A4
Approx $$ spent on mods: $0 (US dollars please)

my best yet wahoo but usually i get about 12, that was the first tank w/ all 8 cylinders running tho so i'll figure it out later

 

Yeah, no emissions in the sunshine state I wouldn't even be able to pass the visual at the moment, much less the actual test (still working on tuning).

 

Any others?

 

Highway: Low 20's
City: High teens

My commute has both highway and stop and go, so hard to say for sure.

Due to this post I am trying 93 octane (have always put 87 in) and seeing if my mileage improves. At least enough for the added cost of 93 octane.

 

'95 LT1 in '92 RS, T-5 5 speed, '95 disc rear with 3.42's, LT4 heads, intake, hotcam.

Hwy/City: 30/18
HP/Torque: no dyno yet
Gears: 3.42
Trans: T-5
Mods: $1500

 

I've kept a running total since I got the '97 in 2000. The average so far is 19 mpg on mixed driving. I kissed 29 mpg once on I10 and it usually runs 16 in straight town driving. Btw, this is no competition car-I even run mid grade gas. It's an M-6.

 

18.5MPG 60/40 hwy/city with several WOT runs everyday
300RWHP/317TQ
3.42 M6, bone stock LT4 Firehawk other than madwolf tuning
was getting 16MPG before tuning

As a reference point, my 01 Z06 usually averaged 18-20MPG over the same route.

 

i've never even concidered putting 87 in my car...doesnt everyone use 93??

 

lol the highest around here is 91, altho my friend gets 110 for his bike, so i might try a mix...

but yay i gassed up today got an amazing 15.7 mpg!!! i was extatic, im so used to low 12's those two wires were really burning some fuel

 

i have a stock 94 m6 with 3.42'2 and 90k and i get 12mpg city and 20 highway

 

I ran 87 for a few months because I was broke and prices were up. Usually run 89 though, maybe 92 when I go to the track.

 

I drive from NC to MD every three weeks and its 410 miles and i make it on one tank of gas.I put it in 6th and cruise at 75 at about 1750rpm. I have roller rockers, 52mm tb, and a pretty decent flowing exhaust so i am amsuming that helps.I get about 30miles to the gallon. oh yea and i have 158,000 on her and she still runs great. As for the gears i have the stock 3.42.was going to go with 4.10 but i didnt want to lose that milliage because i drive that trip so much.

 

For you people with stock M6 cars who get less than 25 MPG on the highway (real highway milage - as in cruise set 70-80 for hour+ per trip):

Your car needs some love! There is no way a stock LT1 with a manual should get low twenties or less unless you drive 90+ on the highway or are really talking mixed city/hwy.

On cross country excursions, I was seeing 29-30 average, with a 31+ best on flat land, AC off. This was both when new and at 100,000+ miles.

Other than that, this has been my often tracked experience:

In Tune - 30/16/12 MPG hwy/day-to-day/hvy ft
Running - 22/13/9 MPG

Only my opinion of course! And again for stock autos.

Sean

 

Well, Ive had the car for 10 years, so I can't remember if I ALWAYS put 87 in. The last few I have, always ran fine. But maybe I should switch.......

BTW, the best I ever got on hgwy was 26 mpg. But I was probably doing 75 mph

 

Back from the dead post...

28 mpg hwy, 22 city.

'94Z M6 conversion
prom tuning, SLP 224/232 cam, LT4 springs, stock rockers and chain. New opti, wires and plugs, u-pulleys, CAI, hooker S/C shorties and borla catback. Total mods: $~750,

Half in tuning, half on engine condition and driving, from what I've seen. Still haven't gone to larger TB, ported heads, LT4 chain or 1.6 rockers and stiffer springs yet...hoping to up it to 30 MPG or 400+ miles/tank and get another 35 HP since it feels as if the valves are floating above 5250 RPM. getting 375ish miles per tank now.