stfuad

The speedometer used to be off, 10mph fast throughout the gauge. I bought the Tuner software associated rom file and the aldl cable to fix this, and get into tuning.

The tire size 225/60/16 came with the car, stock rear end or so I believe code GU2/2.73 gears.

Now the gauge shows 15mph fast. Up to 30mph fast or so I believe, it's hard to tell when everyone speeds. I measured the tire top to bottom and it measures out to about 25.85" as indicated by the Tuner software.

So I suppose I'll have to have a friend with a known accurate speedometer drive in front of me to set a baseline.

Any suggestions would be helpful.

bobdec

Here is a site " http://www.wallaceracing.com/gear-speed.php " You do not have a signature so since you said GU2 2.73 I assume you have an auto tranny. enter the data and check it out. The A4 gears are 1st - 3.06, 2nd- 1.625, 3rd- 1.00 and 4th - .696. As a test , at the site enter tire size 25.85 , gear 1.00, rear 2.73 if you drive the car in 3rd and you s/b doing 62.23 at 1500 rpm. If not your spedo tune is messed up. Also any speed tune errors would be a % difference not MPH, EG 10% @ 30 MPH = 3 mph, 10% at 60 MPH = 6 MPH error. What tuner program R U using ?

EnfuegoZ28

Why does your car have such a tall and narrow tire?