3.08 to 3.73's and JET SCU 2000

[Sean37]

I am very close to buying a rearend with 3.73's and disc brakes. I want to make sure before I buy anything that if I get a Jet SCU 2000 that it will be able to fix my speedometer and get the shift points correct or at least fairly close. If anyone else has gone from 3.08 to 3.73 with this please let me know if you had any problems. So I guess all I have to do is install the SCU and then set the stock tire size, modified tire size, stock gears, and modified gears. And then I might have to play with the modified tire size setting to get the shift points where they should be. So is this gonna work?

Oh yeah and where is the best place to get a Jet SCU cheap? Thanks.

[Harry94]

If you have 3.08 gears then the jet will only work up to 3.42 gears. It can only recalibrate for a 2 gear difference, ie. 3.23 to 3.73, 3.42 to 4.10. If you go beyond this it will get you closer to the correct speedo and shift points, but it will still be off.

[Harry94]

Sorry, it recalibrates for a 2 gear difference or less.

[Magnus]

Get a 3.42 pcm, it will help.

Also, I'm moving this to drivetrain. It's not advanced.

[satellite98]

I brought this up before...

A few people have said you could just program to 3.42 and change the tire size to 24" or something. That'll fix the speedo anyway. Not sure about shift points, never heard an answer on that yet.

[Sean37]

I guess I wont be buying it then. I'll wait until I can find a rearend with 3.42's

[Devilboy28]

You can get a new PCM at www.3800performance.com I called them last week and they said they can program them for almost any gearing. That will be my next purchase.

[Dekay]

I put 3.73 gears on my car and the speedo is off but so what. It shifts fine and just know that the speedometer is reading about 15% higher than you're actually going. It does no damage to the vehicle if you don't fix the speedo. I checked with a couple places to make sure of this and everyone said not to worry about it too much. I've been driving my car this way for a while now and haven't had any problems. 3.73 gears from a 3.08 holy cow what a change. It's like driving a different car altogether.