disavowed10

iTrader: (3)

ive read that some of you are averaging 30+ mpg highway with M6?
if so what are your shift points/avg. speed/octane/upgrades/mods?

my shift points are at 2k and average 80mph highway

jmdale1984

iTrader: (6)

It's not that hard to accomplish in these. When my 00 SS was stock it got about 28 mpg/hywy doing 70-80 mph. But I noticed that the faster I went, the better it did, and it would only get about 26 mpg doing 60-65.

So, after putting in some 3.90 gears... I started getting about 31-32 mpg doing 70-80. It only got better with the new motor, too. Has a baby cam (similar to stock LS7), but the one time I checked it so far, it got 29 mpg in 230 miles. 120 miles being hywy (70-75 mph) and 110 miles being city (including a couple traffic jams).

So yeah... great mileage is easy with an M6. I think the most important part is keeping the motor in an efficient operating range (slightly higher than highway rpms on stock gears, in my experience). I think it's also very important to not have a monster cam and to be tuned well for your mods.

I knew a guy in Dallas that was over 500 rwhp NA (surely not with stock cubic inches), and claimed he was still getting 32 mpg hywy out of his 02 SS M6! If that's true... it's amazing.

69lemansguy

iTrader: (12)

i drove to atlanta and back, and got great gas mileage. did about 80-90 and got 31-34 mpg.

2002_Z28_Six_Speed

iTrader: (19)

+1

I will agree there is something funny to the logic but I have a 4,56 and I get better gas mileage than stock. I just can't go as fast for cruising now. 65 or 70 and I and get a guaranteed 28,7 MPG or up to 31 MPG.

But you have to realise our in towns are much worse. A 4 cylinder car is still going to get better mileage in town or combo. It just works for me because I am almost 100% highway miles.

I think the camshaft/intake selection can influence this greatly, too.

coolformula

iTrader: (21)

100% hwy my 2:73 car gets 32.7 at 65 mph.
I got a 6 speed with .600 lift cam at 70mph pulled down 29 mpg.

So keeping your foot out helps a lot! Thats why I don't see how these cars didnt' sell off the shelf great gas mpg and power.

Z Fury

iTrader: (1)

I've gotten just over 30 mpg on a few highway trips. The key to it all is getting to your speed and just dialing in the cruise. The flatter the road, the better your chances. It is also helpful if you don't run into traffic that forces you to slow down and speed up a lot.

CrimeSScene

iTrader: (9)

I wish....I just checked my mileage and on a full tank I got 286 miles before I had to fill up. That works out to just under 21 mpg. Only TWICE did I even shift above 2,000 rpm. I was hoping for at least 26-27 mpg. I am not sure if it's my tune or what, but my gas mileage sucks for an M6.

ItsNotStock

iTrader: (24)

Stock 01 Z28 M6. On a 120 Mile trip in Montana (roads are not flat, sidewinding curves through mountains and constant ups and downs on hills) I got 30-32mpg in 6th going 90 all the way with the cruise on.

ae13291

iTrader: (8)

i want better gas milage!! o i should clean my air filter. its pretty damm dirty!!

jmm98LS1

iTrader: (28)

These t56 cars are great! The best I ever got when my car was a brand new bone stock auto w/3.23's was 20mpg. Now I've got a healthy cam, built t56, big ol' 9 inch rear, 4.56 gears and heavy 17x11 wheels w/315 drag radials..........and I still pull 24mpg on the highway at 75mph with the a/c on, ~3k rpm shift point in every gear.