chuckb

labor is bigtime on that though and so is the chance of error on reassembly. too bad they never made a 3.55 supra LSD, I think that'd be a nice compromise

JBrady

Ok, that changes the numbers slightly worse and even more definite that a stock tired GS400 with 3.769 gears actually must shift from 2nd to 3rd prior to hitting 60mph. Mind you, this does NOT make the car slower to 55mph or to 70mph. It only changes the 0-60mph time.

Stock gearing gives the following speeds in the following gears at 6100rpm:
1st = 43mph, 2nd = 66mph, 3rd = 100mph, 4th 143mph

3.769 gearing gives the following speeds in the following gears at 6100rpm:
1st = 37mph, 2nd = 56mph, 3rd = 86mph, 4th = 122mph

FutureGS400

OK, I'm a bit confused here I always thought the TRD was just the LSD (clutch type) that was installed using the stock gearing. I didn't know they also made (maybe just "rebadged" ? ) the Torsen LSD.
Are you saying that you used the TRD clutch type LSD and also changed the ring and pinion gears to the 3.76? Or does TRD also sell the 3.76 Torsen LSD (TT Supra)?
The change to 3.76 gears and Torsen LSD made a very big difference in my car! Of course, I also have the PI 2,800 stall TC, but using my Passport G-Timer I can crank off low to mid 5 second runs easily ! (assuming decent weather conditions).
Almost sounds to me like you still have the same gears after all...

JBrady

Lee, you should also be able to launch harder. Get the car on a good rough concrete surface and work HARD at your 60ft times (does the old GTech show 60fts?) At the strip I am consistently 2.20 seconds 60ft times. That is of course with the stock gearing, tires and open diff. With both tires preventing a loss of traction I should be 2.0-2.1. Doesn't sound like much but that works out to 0.1 to 0.3 by the end of the 1/4 ALONE not considering the improvement in time due to the gearing.

JBrady

Good catch MIke...

Lee, what do you have?

redgs4

Ditto. And unless you have noticed a big difference in your day to day driving I'd agree that you have the TRD with the stock gearing.


If you did not replace the pumpkin then you indeed have the clutch type TRD.

JBrady

By the way I just went out and ran a pair of 5.9 0-60s. 60fts were 2.3. Max Gs were just over .6

Darn slow LS400

Lvangundy

Nice JBrady - nearly 6 flat.

The unit I have installed is the *edit Supra TT 3.76 LSD unit. TRD sells the LSD 'piece' separetly for around $900?

http://www.l-tunedparts.com/product/?id=1754

I believe the *edit Supra TT 3.76 LSD 'pumpkin' is a Torsen type, not a clutch type.

JBrady

Lee, five-point-nine seconds.

So, did you purchase the complete LSD assembly from L-Tuned? The one listed in your link is of course the 3.769 ratio torsen gear limited slip. However, the TRD lsd carrier ONLY is not a torsen it is a clutch type. Which did you get? Where did you get it?

DaveGS4

iTrader: (2)

Lee, the piece you bought is 'Toyota', not 'TRD' and that's what is confusing many of us here.

http://www.l-tunedparts.com/product/?id=1754 is the Supra Torsen-style LSD full pumpkin with 3.76 gears, also sold by RMM (and branded RMM)

http://www.l-tunedparts.com/product/?id=657 is the TRD clutch-style LSD. This LSD is inserted into your existing differential and keeps the stock gearing; not a full replacement like the Supra one.

So... don't call it TRD and you won't confuse people

DrewGS4

That is weird,
I have the supra lsd and TC combo and in 70 degree weather I consistently bang out around 5.5-5.6 seconds 0-60mph time.
I did a run lately in 95 degree weather and I had a 6.4 second run.
My best run was around 5.3 seconds in about 60 degree weather.

All runs were done at one location.

Keep the weight the same, get your launch technique down, and keep it under 1/2 tank gas, also watch your tire pressure.

FutureGS400

I hate to say this , but unless you KNOW specifically that you ALSO changed your ring and pinion gears when you had the TRD LSD installed, you still have stock gearing- which of course would explain your unimproved 0-60 times.
Not the end of the world however, you could still change your gearing, just unfortunate to have to do extra work... The good news is that you have an excellent limited slip diff just with stock gears though...

Lvangundy

No, I said TRD but meant what's on that link I posted.

I have the 3.67 gears and LSD.

JBrady

Mike, that is why I asked him what I did. What did he buy? Where did he buy it? Finding a complete Supra 3.77 torsen assembly is getting hard to say the least. I don't even know if there are ANY new ones anywhere anymore.

Lee, what DO you have?

That said, while nice to have the gearing is NOT required to reach his 0-60 goals. In fact it may be easier with stock gearing due to the one less shift to reach this specific speed.

FutureGS400

OK, that's great! The piece you referred to from TRD for around $900 is just the clutch type LSD carrier which has nothing to do with gearing so that's what led to the confusion...
Although as John mentioned, if you bought your "pumpkin" used there still might be some question as to what it is. I know others have ended up with something different than intended so you might want to double check both the gear ratio and make SURE it is the Torsen diff. too.
Sounds like you may be convinced that it IS the Torsen diff. based on your improved traction, so that's good...
John, I understand what you're saying about the change in shift points affecting the 0-60 times, but it seems to me that (unless the car is shifting really slowly) that the improved acceleration rate from 0-55 with the 3.76 gears would more than offset the additional shift from 2nd to 3rd. I will try a couple of runs today (nice cool weather!) and see how the shift point works out.