Guys, I just got my car back I put a 3.91 diff from a GS300 in it. I havent driven it yet but will try to as soon as the rain lets up here in houston.

 

Just drove it was a little slippery outside but it pulls really hard!

 

WOW!!!
That's gona be a blast! 1st gear to
2nd must last about 2 seconds.
I can't wait to hear all about this.
parts & Labor cost? gas milage?
0 to 60 & 1/4mile times? ECU?
Tell it all Brother (as soon as it drys
out down there).

The Hat Guy <<<<(:-)

 

What is a 3.91 diff from a GS300

 

kgmobley,
It is the parts that causes the wheels in the rear
to turn at a different RPP than the motor turns.
The higher the number the quicker the car will
accelerates Our cars (SC430) have a 3:27 ratio.
The parts LexPro used came from a GS300 Lexus.
His SC430 will have a much faster 0 to 60 time now.
His car will give a stock Corvette a good run for the
money now. The Stock C5 Corvette has a 2:73 ratio.
0-60= 5.1sec stock C5 and 5.9sec. stock 430

Just My Thoughts
The Hat Guy
<):-)

 

Sounds great! Let us gearheads know all the info !!

 

Thanks Joe Peters.

BTW, how long before 0-60 numbers?

 

So how much faster is it with the new gearing?

How much did the new rear end cost?

 

Dan,
Is It Dry yet? Is it Dry yet?
We want a report !!!!!
<)))))):-)

 

Dan,

Very interesting mod! The primary problem a few GS owners have had with just switching from factory 3:23 gears to a 3:76 gearing from a Supra is the rev limiter. Under full accelleration the car reaches the redline sooner than the ECU expects it to and it 'bounces' of the rev limiter (causing the car to buck a bit and lose power). This doesn't happen to all GS's with the mod, just some of them. Your change in drive ratio is even greater and I'd be interested in hearing if you run into the same problem.


BTW, with this mod you aren't going to come anywhere close to giving a C5 corvette a run (wishful thinking ), but it should be a nice boost in off the line performance. Top end will suffer, as will gas mileage. May have traction issues .

 

Well guys have driven it for two days now. Gas mileage went from 19.1 to 16.7. Acceleration is noticably stronger(even mygirlfriend said your car gets to speed alot quicker). I dont need to downshift into third to pass anymore 4th works fine and feels like it has infinite pull. The difference in top end is I would say 10mph( i say this becuase I was at 80mph with 3k rpm and now i am at 70mph with 3k rpm). I really like the way it drives you can also feel engine braking when you let off the gas at highway speeds. I dont know how i can get you 0-60 times, i guess there should be some formula that can tell you. Now with this redline thing I think that is totally wrong. I dont see how a manufacturer can program a car to shift at certaind MPH during wide open throttle, they are programmed to shift at RPM's. I dont have any issues with redline and my car shifts now at the same RPM (a little over 6000) and different speeds. As far as traction with VSC off on some surfaces the 20's break loose but these are tall tires and grip pretty well.
I was able to get the rear end from a friend who has a salvage yard at 0$ cost and a friend(tech) put it in for me for 150$.

 

Dan,

Can you post the exact model and year for the rear? I'm really interested !

How about the approximate time to install? If I can get use of a lift somewhere, I just may attempt it myself.

Is the rear specifically from a GS300?

 

All 98 and later gs300 rear ends will work. The time to install took 3-4 hours.

 

Dan,

Is this a pure swap (bolt off, bolt on) or is there any drilling/tapping involved?

 

Pure swap! No customizing.