downwithmustang

I have the stock rear axle thinking about go with a 3.73 with my A4. What's the gas mileage like on them? Do I have to recalibrated my speedo or anything at that matter?

2001NBMZ28

I went from 2.73 to 3.42 and lost about 4 MPG highway, if you have 3.23's you won't loose that much. You can compare the RPM differences using a calculator like www.f-body.org/gears/ And yes, you'll have to program the PCM for the new gear ratio to keep the speedo/odo correct.

a4z28

I have them in my a4 and honestly maybe i lost 3-5 mpg but what i got in return was a smile i just cant shake off. So with just the gears i would say maybe 2-3. And you will need to recalibrate your speedo. I went from 2.73 to 3.73 with a 3000 stall

downwithmustang

What about city?

a4z28

1-2 mpg in the city.

cas0484

I get 15mpg city with 3.73 and a 3000 stall but some others with the same mods and small cams get 15-17.

downwithmustang

Well I have a stock LS1 whats the og city/highway on them? Would a 3.55 gear save gas?

WestCoast96Z28

With the mods in my sig...I get about 14mpg....probably 3/4 city and 1/4 highway. Yeah, it sucks. Ironically, I drive my SUV sometimes to save on gas. Brutal.