Could someone tell me if my car has to be reprogramed to go from my 2:73 rear to a 3:23 or even a 3:42? Mine is an automatic, '94 Z.
Sorry to sound dumb but I'm still learning about computers...Thanks

 

Yes, you will need a computer program, your speedo will be off. Also the computer shifts according to mph and other variables, not according to rpm. So you may have problems hitting your rev limiter.

A hypertech power prgrammer should do the trick. Its not to expensive and pretty easy to use.

 

Thank you! There are a lot of people telling me different things, if it wasn't for this website I'd be crazier than I am now!..Thanks

 

MadZ28.com can also reprogram you pcm. I traded off my hpytech and whet this route.

 

Thanks, although it seems like they're shut down right now.
What would they charge for that?

 

Never mind, I found the price button! Thanks....

 

I never reprogrammed after going from 2.73's to 3.73's and my speedo is right on...

90mph I'm at 3,000RPM's
70mph I'm at 2,400RPM's

 

If your gear ratio was changed then it is impossible for your speedo to be correct without telling the car it was changed. Those mph and rpms sound like they are for a 2.73 car.

If you do new gears, the car doesnt know that and it will read the same as it was before. So you are actually going slower. (if you go with a numerically higher gear ratio.)

 

Ive had these 3.73's in for close to a year and I can tell you that the RPM's above are correct.

 

So you are saying you just popped 3.73 gears in with a stock PCM and your speedometer is reading the correct speed?

Looks like yout MPH and RPM is correct for a 3.73, so that means something was changed to correct it.

 

Never said the PCM didn't have to be reprogrammed, simply stated that I haven't touched mine...

I've made many posts concerning gears so I do know what I'm talking about...just stragne how my PCM didn't need to be reprogrammed...