30+ Mpg?
if so what are your shift points/avg. speed/octane/upgrades/mods?
my shift points are at 2k and average 80mph highway
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.
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.
Last edited by 2002_Z28_Six_Speed; Jun 26, 2008 at 12:29 PM.
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.
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