nudderGS400

First, thanks to Adrenaline Motorsports in Canada, the source of my '95 1/2 Supra TT rear. Turns out the unit is in excellent condition, just as advertised. Thanks Phil!

Second, I would recommend BodyMotion in Amboy, NJ for this type of job, impressive shop and staff (littered with Porsches though). Not cheap, but thorough, and easy to deal with. Plan to get my SRT intake done by them next week.

Impressions;

After a few days with it (approximately 700 miles) it is a must have. For me, it doubled the fun quotient. Feels like a much stronger beast in almost every situation. Much, much quicker off the line. Just as much fun at highway speeds. I don't know how I did without it.

I wanted it because;
from a stop sign or light, one rear wheel would spin very easily when turning a corner,
traction control came on way too often,
hoped it would help in the snow.

Now, when stopped, I can accelerate much harder before they break loose, and now when they do break loose, they do it together and keep on pushing, the traction control doesn't even kick in. Not yet anyway, will keep trying. However, the VSC does kick in and try and keep the car straight (probably a good thing til I get used to it). RPMS are affected as many posts say with the 3.76 ratio, gas mileage is down 1-2, but without the resonators the new sound at highway speeds is great. Just a little louder, doesn't seem to be working too much harder.

Had a little snow too! Much better in the snow (also thanks to Conti Extreme tires). What I noticed was, once again, that the car keeps pushing and the VSC comes on only to keep it straight. (Less than an inch of snow, one day only.)

With the LSD, I would re-prioritize my performance mods from must have down as; 1-Bilstein/Eibach (should have done coliovers though), 2-TRD race sways, 3-LSD, 4-front STB, 5-steering ECU, 6-Toms six piece kit, 7- lose center section resonators, 8-tranny cooler, 9-rear STB, 10-front LCB.

SRT intake going on next week. Will give you my impressions on incremental performance gain, relative to LSD.

PS- saw 'LEXMATIC' on the Southern State today. Is he a CL member? Nice blue GS.

D2-AUTOSPORT

nice writeup man, with large wheels, i really wanna do this mod to shorten my final drive ratio and get better performance, enjoy it!

presto

I'M excited about the possibilities with the LSD. It seems that the 3.76 gives the most low end torque and overall acceleration compared to the TRD. Is this correct thinking on my part?

It also seems that the cost of RMM and TRD is close to a wash when you factor in the labor costs.

I want to make sure about a few points. Does the shift sequence still seem Lexus smooth and quiet?
How is it to drive in the city?

I have 17" stock wheels with new Firestone Firehawks along with TRD shocks, Eibach springs, TRD sways, L-tuned steering ecu and a tightened steering rack on my 03 430.

It seems that the drivetrain is the next step. Let me know your answers.

nudderGS400

Presto,

It definitley improves the low end torque and acceleration, not that the GS4 needs much, but with both tires working it is applied to the street instead of just making noise.

Other posts have suggested that the real cost is about a wash, I would tend to agree. It would seem to be more a choice of whether you want the TRD with the clutch pack and standard gearing or the Supra/RMM torsen type with 3.76 gearing. Main difference is that you can find the RMM rear used much easier (Supra Auto version that is). I got mine for $600 plus shipping.

It drives very smooth, just seems a little more responsive with even a light press on the gas. Normal driving is relatively unchaged except for higher RPMS.

I also am running stock 17s. You should be very happy with it if you decide to go that route.

D2-AUTOSPORT

nudder, this may be tough to answer, but how much top speed have you lost? Have you ever taken to top (or close to top) end before/after the LSD.

Not telling you to go out and be stupid and reckless, maybe on a really long trip/ secluded highway type deal

redgs4

There have been several threads on the reduction in top speed due to the 3.76 gearing. The new high end is around 135mph. Note: This is due to a speed limiter, not topping out the RPM. You also have to be careful buying a used supra rear end. Aside from the usual wear and tear, not all were limited slip. You will end up with the gearing and not the LSD.

Hameed

Write-ups such as this are always exciting to read!! I am sooooo looking forward to getting mine installed in about 4 weeks or so when my car comes out of winter storage!!!!!

I noticed that you have not done the PI/TC mod. Any particular reason why? Other members here like Bitkahuna who have done that mod, swear by it and strongly feel that the LSD mod should only be done with the TC mod simply because they complement each other and the install cost to do both at the same time would be less than doing them seperately.

You definitely sound very happy with the LSD mod only, I can't imagine how much more happy you would be if you did the TC mod as well. Higher stall speed of 2800 rpm would launch you even faster!!!

D2-AUTOSPORT

Since 20" wheels give my car a taller final drive ratio than stock, I wonder if my top speed would be slightly higher? I would like to still be able to visit 140 or so when traveling late nights in the deep south!! LOL

bitkahuna

iTrader: (20)

nudderGS400 - I share your impressions completely! CONGRATS. As Hameed said I have the 2800 rpm Precision Industries (PI) Torque Converter (TC) in my car also, which I put in first actually (because I didn't have the Supra diff at the time), and the TC alone makes a HUGE difference in performance and IMPROVES driveability because the tranny down shifts more easily.

For those not familiar with these two mods let me try to explain:

The torque converter provides a kind of variably slipping linkage between the tranny and diff I believe (?). It's like two halves of a bagel with fins inside. The fluid inside is spun by one side of the bagel, which gradually makes the other side spin until a certain speed when the two halves are locked, spinning in unison. This locked speed is called the stall speed. The stock torque conveter is fully locked at 1800rpms which means the car is trying to apply all the torque available at 1800rpms to the rear wheels. The PI TC can be ordered with a different stall speed, and many have a 2800rpm stall speed in their GS4's, including me. This basically means the engine spools up closer to 2800rpms before max. torque is applied to the rear wheels. In practice it makes the car feel more 'free revving' and since more of the car's maximum available torque is on tap at 2800 instead of 1800 the car just feels (and is) a whole lot quicker. Several told me before I did it though that the Lexus tranny would feel smoother after I installed the TC, and that is in fact the case. Because more shifts may be done at higher rpms than stock, everyone recommends putting in an extra tranny fluid cooler when installed the TC. I had a B&M racing cooler put in, in front of the radiator up high near the horn. So in summary the 2800rpm TC puts more of the available torque on tap quicker when you drive making the car more responsive. It's a hoot.

The TRD LSD is a clutch type 'ball' that replaces the inner workings inside the differential, and must be precisely installed. Very few have done this as far as I know. I had a TRD LSD in my possession for a while but couldn't find a local shop I felt comfortable with to do the install. In the end I sold it and bought a Supra Torsen differential, which is much easier to install because it simply replaces the entire stock differential.

While there's debates about which is better, clutch type or Torsen type, (I've heard the clutch type can handle more power, but we're only talking if you have turbos or supercharger maybe), either is fine for the job.

An LSD will help you get whatever power you have to the ground much more effectively than an open diff.

I could so relate to nudderGS400's comment:

This bugged the heck out of me - I came to call the VSC 'the nanny'. All that available power so often being applied to the WRONG wheel (the one with the least traction) and then the VSC would say "whoa boy - I'm stopping this fun".

So the TRD or Supra diffs will help this immensely. BUT, while the TRD LSD uses the same ratio ring gear (3.26 I think) as the stock diff., the Supra Torsen diff uses a 3.76 ratio gear, which basically means the overall gear ratios of the car are lower than stock. This means that more rpms of the engine are needed to turn the wheels the same amount. This might sound like it would make the car slower, and it's true that it lowers the maximum speed of the car, but it significantly improves acceleration!

So the Supra diff not only lets you use the power more effectively, it also increases the available torque through lowered gearing. And combined with the PI TC which puts the car in the 'sweet spot' more often, the combo is incredible!

Anyway nudderGS400 - I was happy to read your comments, you captured it perfectly.

presto

A couple of questions regading the 3.76 LSD...What happens with the ect switch on the console(power/norm/snow)?? any changes??

and what happens when you drive it in "4" instead of "D"??

Let me know because I think I'm going to get the RMM LSD this week.

I do remember when I originally test drove a GS 300, it had better (slightly) low end torque off the line than a 430. I realize that after 30mph the 430 spreads its wings. Apparently there is a gearing difference between the 300 and 430 which would explain the 300's low end torque. That's why I'm ready to go for it, and do a 3.76 in a 430, it seems like it makes alot of sense.

bitkahuna

iTrader: (20)

Works the same. I still leave my car in PWR all the time.

I'm not sure where you're coming from. I use the 4 setting a lot but it's less necessary than it was before the LSD because the rpms are a bit higher, so the car downshifts a bit more easily. Don't know about you, but I found the stock tranny/TC/diff conspire to keep the car in 5th too much and reluctant to downshift.

Good luck!

nudderGS400

I would echo bitkahunas comments; however, I used to run with PWR on all the time, but now, it seems not to do as much. The shift points and acceleration seem less different with the LSD.

DGOT20s - I just took everyone elses word for it that the speed limiter would determine top speed, not planning on trying it.

RedGS has a good point also, lots of dissapointing threads about people who didn't get what they wer looking for. I had them count the teeth and make sure it had 49 before they shipped it, then I counted when it came too. Buyer beware, best to prepare, reasearch alot before hand.

Regarding the PI/TC, I wanted to seperate all the mods and do them one at a time to feel good about the investment. Wanted to make sure it produced the desired affect. The LSD defintely did. But it launches so quick now, I am not really thinking about the TC. IAlso, I don't think there is any real cost savings in labor to install both at once. Anyway, I am not sure if I would like it to be any quicker off the line now, I can spin them both way too easily now.

Just my opinion though, I know some guys out there swear by it.

PS - Presto, you'll love it!

UK_GS300

Does changing the diff throw out the speedo and odometer?

bitkahuna

iTrader: (20)

I don't think it does - I believe those are driven off wheel speed sensors.

Now my 19 rims and fat tires did...

Lexotec

Can U please specify the Years of the supra's that HAD the torsen LSD?
I know U said yours is a 95 1/2.
Also the Contact # for Adrenaline Motorsports? If U don't mind.

When U are accellerating do U hit the rev/limit? or does it stop short before 6,500RPMs when U change in M mode?

I have read that the Torsen is good, but the TRD clutch type is better for snowy or muddy conditions.

So the Torsen type is better for 0-60 than the TRD unit?

thanx