checking gear size

webbs7mgte

New Member
Jun 2, 2008
298
0
0
wisconsin
How can u check wat rear gear size u have I know its a lsd set but idk if its the 3.90 or 4.30 is there a way the vin tells u ?
 

Jeff Lange

Administrator
Staff member
Mar 29, 2005
4,919
4
38
37
Sunnyvale, CA
jefflange.ca
Yeah you can tell from the VIN.

Or you can look at your data tag on the car to get the axle code.

Or you can know that N/A's have 4.30:1, 87-88 Turbos have 3.91:1, 89-92 Turbos have 3.73:1. All Turbos have LSD, and some N/A's do too. They're all 8.0" Toyota G-series differentials.

Jeff
 

Angry7M

Formerly redmaro
Sep 6, 2007
733
0
0
35
AZ
So do you guys think its a big difference in acceleration from a 3.7x to a 3.9x ?

For example my friends Mustang GT has like a 3.3x (something like that) and he bought some 4.10's and installed them. Now the car has a great launch but on roll races it falls flat on his face.

I was thinking of changing to a 4.30 but hows acceleration on Turbo Mk3's on roll races? Or are the stock gears better for roll races?

Ohh and i heard something like the turbo takes longer to spool with 4.30's at from a stop. Would this also apply when changing from 3.7x to 3.9x? LOL too many questions i know
 

87CandyBlueT

Banned
Feb 8, 2006
553
0
0
38
Kentucky (NKY)
I haven't driven the 3.73 but My 87 turbo 3-3100k RPM around 78mph or something I think I can't remember for sure what it was when stock.

I will say that it is a top end car.

155 on the highway and set the cruise ;)

I don't think I would swap rear ends for playing on the street.

Drive your car and you'll know what you want.
 

annoyingrob

Boosted member
Jul 5, 2006
2,304
0
0
Calgary, Alberta, Canada
redmaro;1125421 said:
I was thinking of changing to a 4.30 but hows acceleration on Turbo Mk3's on roll races? Or are the stock gears better for roll races?

How's your power delivery?

I run 4.30s in my car, but I have tons of power from 4k-7.5k. If you have a narrower powerband, you could very well fall out of it on a shift.

They make for a wicked launch on slicks, but on the street, I have lots of traction issues with a 4.30, and highway cruising sucks balls.

Another thing to keep in mind is it's difficult to re-gear the R154 speedo drive for a 4.30 rear-end. How the PO did it on my car, I have no idea.