Anyone know who can calibrate a speedometer and tachometer for different wheel size and different final drive. Mine is off by about 8% at 60mph

 

What diameter tires are you running!??

Speedometer is not affected by final drive ratio changes because it actually uses the abs wheel speed sensors

 

You sure thats for all models?
I've seen the speedometers be effected on the 06/07 models when the FD was changed.

 

IDK, might be different for newer ones, but Cory's is a 05. I really thought those went off the WSS

 

^It might. The 05's are weird since they share some characteristics of both the earlier and later models.
Don't know the answer but I inquired about this once at a dealership and they told me the cluster would have to be shipped off somewhere inorder to be recalibrated.

 

That's what I thought too but people keep saying it. And I'm running a 245/35R19. I know its barely off

 

how do you know it's off 8%?

 

That tire is 2.2% different from OEM sport 235/45-18s

The Spedo also isn't accurate so I am not sure how you are measuring your %

To me you are only 2.2% off

 

Wait a sec,
Danny, yours is an 05 and you changed FD ratio. Did it affect your speedometer?

 

I have 245/45/18s on coupe 18s in the rear, have around a snug 3 finger gap. Planning to drop on full revised Z, how much should my fenders be rolled? What's the disadvantages of rolling flat vs. Just rolling?

 

do you have spacers on? and there aren't an DISADVANTAGES of doing either, rolling it more just give you more room to put a bigger spacer or bigger tires on

 

Thanks, I don't have spacers, they're pretty flush as is on a sedan...I've seen people on the forum who say they didn't roll their fenders flat. If there are no disadvantages of rolling flat, why wouldn't they have done so?

 

They either didn't have the legit tools to do a real rolling job because they didn't want to pay somebody to do it or they just rolled them enough to fit their setup....some people are really against rolling their fenders at all but there is nothing wrong with doing it

 

I've read its possible water can get trapped in the rolled area and rust, I assume a professional fender roller would use a sealant or something?

 

I've never heard of that happening to anybody....mine weren't sealed and i haven't had any problems....with the angle of the fenders the water shouldn't get trapped up anyways....some people get their fenders "pinched" which basically means their is no possibility of any space between the two peices of fender