QBranchCars

I have been informed by fellow members I need a Limited Slip, especially if I track my car often. I need your opinions and comments.

TRD does make a LSD which is available for $800-900, but it's not a complete assy. The dealer book rate for install is ~$700. Also, there's no low gearing for the TRD unit, so I would have to buy also a TC (torque converter) for $900 and another $400 for labor.

The RMM LSD is a complete unit, for $1600 or so. Labor is only $200 for install. The RMM unit also has the lower gearing, so i would not neeed a TC. I'm a little concerned with the quality of the RMM LSD. Does anyone have any experience with it?

I have been told a Supra diff should also work, but I'm not sure if it has the low gearing. It should be easy to install like the RMM. Comments?

Thanks

Mariusz

I think regardless of which LSD you get, the quality should be comparable.


If you decide to go with RMM, I can get you that LSD for $1399+shipping.

Babalouie

AFAIK, the part number for the TRD diff is the same for the GS4 and the Supra, so it should be a bolt-in, bolt-out job.

And I think the gearing is the same, both Supra and GS4 have a 4.083:1 final drive?

JBrady

QBranch, why do you want the LSD? I would STRONGLY recommend starting with the TC from Swift. Call them, thank me later.

http://www.swift-racing.com/

Mean Gene

Calvin - My understanding is that the RMM LSD is a twin turbo Supra piece with 3.76 gearing. I don't autocross but I'd like the steeper gears to get me off the line & out of the hole quicker as opposed to the factory 3.26's. I've been very pleased with my RMM 3.76 LSD as I need the gearing to overcome the stereo weight in my trunk. However, as JB says, the TC made a bigger difference for me in off-idle performance than the LSD. In fact, I had the TC first & could fry the tires but when I added the RMM LSD, the equal power distribution made it harder to spin them but easier to get the power to the ground. TC + LSD - Not a bad combination!

QBranchCars

Mariusz, I'm in California. Would you charge me tax?

hlee1169

Mean Gean,

With the RMM LSD and shorter gearing, do you know what RPM you are running at 70 MPH? Do you like its performance? Thanks.

Mariusz

QBranch, NO tax.

Mean Gene

HL - I don't have access to the car right now but I think it turns around 2800 rpm's at 70 mph or close to it. I've been very happy with the addition as it dropped my 0-60 times by about .1. Unfortunately, it makes it darn near impossible to spin the tires but that's what the LSD is for - to get the power to the ground.

Woody1

I have a RMM LSD I bought from Jamie Zartman (few of us old timers may remember him), but I haven't ever gotten around to have it installed. It's slightly used, but looks great and has original crate. Jamie told me usage was minimal. I don't really want to sell it, but I'll entertain offers.

E-mail me at brad@woodyselectronics.com

Grush

What exactly does the TC do? Allow the rpms to raise before the car roles? What are the off-the-line charateristics?

Sorry for the rookie-like inquiry...

LexusRules

i belive itslike a clutch:

in stock form it grips/locks much more gradualy, so you don't get all of you power until a certain RPM

with the new TC it will lock up the tranny/engine much quicker therefore giving you all you power downlow.

not all your 225/300HP but the expected HP at that RPM.

Mean Gene

Sasha - Actually, it's the opposite of how U described it. The factory TC locks up at a lower rpm to maximize fuel economy & lower tranny operating temps. Not sure but have been told that it's of about a 1600-1800 rpm stall design. The Dragon TC stalls at 2800 for the naturally aspirated design & 2500 or so for those with the S/C ( due to their increased low-range rpms torque ). This higher stall allows the engine to slip up into it's powerband ( 3000 rpms ) quicker & give the good launches. Basically, a TC is a viscous coupling between the engine & tranny & serves the function of torque multiplication. It doesn't make power but allow U to use what U already have better.
Grush - the car will begin rolling as soon as U let off the brake. Some folks think that the car won't move until the TC locks up at it's designed stall speed - NOT TRUE!

Grush

Thanks Gene! So if I just accelerate normally from a stop, what difference would I experience over stock?

And with heavy accel from a stop?


Steve

LexusRules

i'll just shut up now...