I've never heard of that type of gain....ever. You do limit the amount of air that flows underneath the car, but I could see 0.2 MPG, no 2. lol

I do have 20's but Ive def seen an increase. Its a solid 2mpg on the hwy. I usually cruise at 80-85 maybe thats why?

Idk. Did you recalibrate your speedo for the taller wheels and tires? If not, you are turning less RPMs, so that may be part of the equation.

Well when Ive had the 20's for about 2 months now and they are the same height as the stock 18's. The increase was seen after the 20's? LOL Its really weird.

If they are the same height, then maybe those weigh less than the stock setup. Only other explanation.

Fuckers are light by any means but the rears are close to the same weight.

When i was NA, i had 3.73s and got 24 on the highways. closer to 21 mixed driving

now im boosted, i have 3.31s and get 22mpg on the highway. closer to 19 mixed driving.

So today I used the mpg avr and reset. To work 16 mph. Back home with adv sport mode activated, got around 19. I did make an effort to go easy on gas. tomorrow I will reset again and run sport mode each way. And drive like my normal self. ( disclaimer) I only drive like 8 mile each way so not much of a test.

What is sport mode?

-Alex

Ok, at a stop, foot on brake, double tap the console button most to the front by your gear shifter. You will see the spin control off light on left and advance track on.

Sweet! Like the competition mode of the C5 I had. I'll give that a try. I was driving with traction control off because I thought it was the only option.

-Alex