I've searched around but haven't been able to find an answer with the keywords I've tried...

Curious as to how many extra miles added / how far off the speedo will be on my '99 if I was to install the new 10bolt without recalibrating the PCM? I have the new rear sitting in my storage building right now and I'm anxious to bolt that thing in I haven't planned on getting the ECM reprogrammed until after I do the heads/cam approx. 3 weeks from now.

I can deal with having the speedo off, I can compensate for that until it can be corrected but I don't want to add a TON of un-actual miles to the car due to the higher ratio. I'm basically wanting to know if I was to put 100 actual miles on the car.... how many miles will the car THINK was put on it due to the 4.11's out back?

I'm sure there's a formula some where out there to calculate it but I haven't been able to find it yet

Thanks

 

This is how it would work:

I am gonna assume you have 3.42 gears with the 6 speed

4.11/3.42=1.20
So 100miles*1.20=120.2 miles recorded

 

where can you get recalibration? thanks

 

I do them, what are you looking for?

 

That's exactly what I was looking for... it crossed my mind that the formula may be something like that but wasn't sure. Hrmmm guess an extra 100 miles or so being added to the car wouldn't be that bad.

Thanks

 

Unhook the speed sensor and just roll with traffic. My 92 firebird's speedohasnt workeed since i swapped trannies and the only good thing about it is the 214k hasnt went up any since

 

Here is a site with some useful calculators:

http://www.smokemup.com

The only bad thing is you have to register... though it is free.