going to change gears out.

Have tunerpro, cables, tunercats

HELP !!!!

 

Including a "Signature" with basic info about your car - year, model, engine, trans and any major mods will help people give you more accurate answers.

Left click on "User CP" on the red task bar at the top of the page, on the dropdown, left click on "Edit Signature".

 

ok - changed my signature....

 

i just sent my ecm out to pcms4less and they took all my info and reprogramed it for me works great

 

In LT1_Edit, there's a screen that allows you to enter the tire size and the rear axle ratio. I would assume TunerCats has something similar.

 

Tunercats does. It will do all the calculations for you and then you can have it enter them into the file. Or you can do it all manually if you want to.

 

I assume your tranny is a 4L60E... As DOOM_Master stated when you go to the speedometer setting utility in TunerCats you will get a Pop-Up that asks if you want to alter all the settings. If you select the option it will reset all your shift tables to match the new rear gearing. I your case the shift point RPM's should increase 36.6% across the board. I have heard some say they were not happy with the utility results, but they never explained why. I myself updated the tables manually to make sure they were exactly where I wanted them. Also worked with Solomon (LT1pcmtuning) and he moved some of the lower gear shift points up sooner with some pressure tweaks to get a snapper response. With your 'CRT Race Built transmission' you may already have modified tranny settings, I'm not familiar with that setup..

 

I am using TunerPro to edit the program and TunerCats to just shoot it back in. So everything is going to have to be done manually. The gears are going in on Friday. I went through every table I could find that had a MPH related setting on it and multiplied by .73 to lower the MPH at which that event took place. I believe from my research so far that this should be correct.

One example are the Kickdown Mode Up/Down Shift Points. Shown are the original values followed by my new values.

1>2 48.......33MPH
2>3 92.......64
3>4 150.....104
2>1 29......20
3>2 86......60
4>3 142.....98

There are a few other setting which I can't seem to find any explanation for related to the Speedometer. Shown below are my original values and what I THINK are the new correct values. This is based on multiplying the original values by 1.366 which is 373/273.

Speedometer Scalar 22..........30.052
Speedomter Scalar, Fraction 36.22.............49.77
Speedomteter Scalar (Scan Tool) .99................1.35
Speed Pulses Per Driveshaft Revolution 40.02...........40.02 (left this alone - you should still get the same number of pulses per revolution)

Can someone confirm or deny my calculations?

As a last resort, I guess I will have to break down and buy another program that just allows you to input the gear ratio but I was trying to avoid that.

COMMENTS - THOUGHTS ????????

 

Here is what we finally figured out......

My multiplication in all the tables for shift points x .73 seems close - may need to do some small tweaking but good starting point.

Speedometer Scalar (Scan Tool) was put back to .99 and all seemed good.

So here are the final values we used

Speedometer Scalar 22..........30.00 (calcluations are 30.052 but it rounds off)
Speedomter Scalar, Fraction 36.22.............49.77
Speedomteter Scalar (Scan Tool) .99................ 0.99
Speed Pulses Per Driveshaft Revolution 40.02...........40.02 (left this alone - you should still get the same number of pulses per revolution)

 

do you have a stall? if you do read up on the problems associated with programing for a stall wall issues

 

2800 stall converter was installed by CPT when trans was done.

 

With a 2800 you may be OK, keep an eye out for DTC 24 (VSS error) sets when tranny tail shaft (VSS sensor) less than 250 RPM and engine RPM greater than 3000 . It will force tranny into safe mode until ignition is cycled off/on. To fix set the the VSS diagnostic enable RPM constant higher than 3K RPM.