Hello

I have a 94 Camaro Z28 with 255-35-20 tires on it. I was wondering how i would alter the PCM with the USB ALDL cable I own to correct the spedo/transmission shifts/ect. Also, if I were to correct it, or atlease the power ratio with gears, what gears should i get. 3.7x?

 

First, figure out what size tires you have. Both of them seem too large to even fit in the wheel wells. A 255/45-20 is 29" diameter. A 245/55-20 is 30.6" diameter.

You need program software like LT1_Edit or TunerCat to access the PCM and adjust for tire diameter. I'm not sure that the PCM will even accept tire diameters that large.

To determine what gear ratio you should get, you have to tell us what tranny it has, and what mods it has. You're probably going to need 4.56's with a 29" or 30.6" tire.

Could you post a picture.... I'd like to see this.

 

Do you have datamaster or LT1 edit?
thats important to have first.
and are you asking about what gears you want to buy or what gears does your car have?

 

how can the speedo be calibrated on a 93?

 

Correction - tires are 255/35/20
car picture - Herehttp://i21.photobucket.com/albums/b2...3061d7b1bf.jpg
I have datamaster and freescan. LT1 edit is reallly expencive, is it worth it?
Also, what gears do i need, i really dont care what gears i have, lol, cuz there most likly stock. The trannys a 4l60E.

 

with datamaster I believe there is a tire size setting and also a gear size setting. I'd go with 3:73's unless you drive allot of highway then i'd just stick with 3:42's they give you the best of both highway and in town driving without killing your gas mileage.
if you need more than this I'd go over to the computer and diagnostics area and see what help those guru's can give you. I've tinkered a little with datamaster but I don't wanna tell you what might be wrong. Good luck and enjoy the Z!

 

You can't "tune" (or change parameters like rear axle ratio and tire diameter) with TTS DataMaster. Its just scanning software. You have to use LT1_Edit, Tunercat, or (heaven forbid) a Hypertech Power Programmer (assuming it can enter a diameter as large as 27.0").

 

I thought tunercat was datamaster!

 

No.

http://www.tunercat.com/

http://www.ttspowersystems.com/

 

I feel like an idiot!!

I have tunercat then! Not datamaster. Learn something new everyday!