A big hello to everyone on the forum. I am a 23 year old small business owner from Northeast Indiana. Just over a month ago, I purchased a 1996 SC400 with 58k miles. I am the second owner. I love the car. It is in fantastic shape as the original owner took excellent care of the car, having already performed a 60k mile check that included a new timing belt and fluid flush.

I chose the SC because of its performance, reliability, and value. Having been the previous owner of only a 1993 Ford Taurus GL, 260 horsepower is a new experience. At the same time, I am looking to upgrade. With the money I saved over a GS4, M3, S4, or CLK55, I am looking to invest some of the difference into upgrading the performance of my car into a similar ballpark of performance. Currently, my SC is completely stock.

I have completed a good amount of reading on this forum, intellexual, planet soarer, lexus owners club, and lextreme. The torque converter by Precision Industries appears to be a must have to increase off the line acceleration (something I value highly). It is universally considered a "Great Mod", and it is something I am definitley ordering and installing in the coming weeks.

After the Dragon, I plan on adding an LSD to compliment the additional low end torque. I have read that certain Supra Torsen models are easily compatible. I also notice that TRD makes a very good LSD that works with the SC400.

My questions are these:
(1) What is the difference in functionality and performance between a Supra Torsen and TRD LSD?

(2) What is the difference in compatibility between the stock drive mechanisms and a Supra Torsen or TRD LSD?

(3) Specifically, what models of the Supra Torsen and TRD LSD should be found?

(4) How does one go about finding and/or ordering the Supra Torsen and TRD LSD?

(5) Once purchased, would I use a transmission shop to install the part or would I be able to do the differential transplant myself?

Thanks in advance for any insight that can be offered. It is appreciated as I am new to teaching myself the ins and outs about cars (specifically the SC400)-
Blizzy

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As a postscript, if this attack plan as a "bang-for-buck" 0-60mph acceleration upgrade seems flawed to anyone, please feel free to offer any suggestions.

**My goal is to drop my 0-60 time under six seconds to bring my 96 into a more modern era of acceleration times for a luxury sports car.**

 

Welcome to the site.

For all your questions...The Search Button will give you the answers.

 

yeahh....i dont know anything...but the person above OBVIOUSLY doesnt know anything either....
just to let you know... there are ganna be lots of

"durr....please use search button durr...." (which is obviously not helpful...)

even though MOST of your questions could be answered through the search button.....

but yeah...just ignore the people that say the line above and you'll be fine

welcome to the club!

 

I have had my good and bad times with the search feature...I must just have to get better with it. I appreicate any efforts and answers, even the "I Don't Know; Search for it" answers.

Thanks for the welcome. I am very interested in learning a lot more about my SC400. I hope to give back to the forum by keeping well documented results of each of my upgrades.

 

I have no comprable input inregards to supra torsen vs TRD torsen, however i know that you'll need to find the torsen diff from a non-turbo, automatic supra.. JZA80 MKIV if i'm not mistaken.. its a relatively straightforward swap that almost any monkey with an ounce of mechanical ability can acheive at home.

its highly reccomended that you do a gear oil change on the replacement part first, if only to inspect for shavings/filings on the plug, or in the oil itself.

bolts straight up.

the idea of using the non turbo supra torsen, is to retain the factory gearing. unless you want to recalibrate your speedo to suit the new centre ratio.

of course, all JZA80 supra diff's will bolt up.. as far as i know.. so.. it depends if you just want the LSD function whilst keeping your standard ratio, or if you want something that sits a little higher in the food chain for that snappy take-off....

that said.. i'm an aussie.. speaking from experience over here.. you'll also find that JZA80 brakes and suspension swap over nicely too.. as well as the driver 's seat if you find the soarer/sc seat a little high for your liking..

 

How would the "snappiness" of take-off differ from one Supra LSD to another? With my main goal being quickness off the line, would I be best off getting the "snappiest" of the LSD's?

If I went with a different drive ratio for a quicker release from the line, how difficult would it be to recalibrate the speedometer? Is this something that the Lexus/Toyota dealer could do? Is this something any good mechanic could do?

Ultimately, I am looking for the best launch possible with the SC using the TC/LSD combination. I suppose I should rephrase some of my original questioning:
(*) Which SC400 compatible LSD would best work with the Dragon torque converter to maxmize off the line launch capabilities?

(**) Could an LSD be so "snappy" that I really struggle with traction off the line even with the limited slip protection?

 

And this comment and post helps how???

I wasn't being mean or sarcastic, I was just pointing the guy in the right direction. Oh and I do know the do's and donts to the SC LSD swap questions. But I, like others on this site learned from reading other posts about it.

Grow Up man....Get over it

 

You won't notice the difference between the supra and trd lsd if you aren't hardcore drag racing.

I have the TRD lsd coupled with a rear end from a supra. The reason I have the rear end from the supra is the gear ratio. Not sure what the gear ratio is anymore since it's been so long.

My suggestion is to get a TRD lsd and install it into your sc. It should fit. Call Dusty at www.mvpmotorsports.com and he should be able to help you out. The reason I say get a TRD is beause it's impossible to know if the supra rear end you are getting really has a lsd in it. I would bet that half the people here who bought supra lsd's don't have lsds because they never opened the pumpkin up to check.

In regards to your other questions, do a search. There is a list of what supra rear ends fit and the gear ratios per year.

In regards to performance, I have the PI torque converter and the TRD lsd. It launches great. The TRD lsd makes a world of a difference. Before, I used to spin off the line when I launched. I mean tires spinning, smoke everywhere type burn out. I was launching hard today and I get brief spin, chirp, and I'm off. And don't forget to get a good set of tires. Once I finish off my current tires, I'm getting drag radials.

 

(1) How badly does the TRD product effect the accuracy of the speedometer? Does it effect the odometer as well? To what degree and in what way does it effect both?

(2) If I will not notice the difference between a supra LSD and a TRD LSD, why would I not buy the Supra LSD that maintains speedometer integrity?

(3) Am I able to get a new Supra LSD from a Toyota dealer directly so as to eliminate getting swindled?

Regardless, the LSD+TC combination sounds like it is exactly what I am looking for.

 

The lsd itself will not cause misreadings in the speedometer or the odometer. You need to do more research about what lsd's if you believe the unit itself will cause an innacurate speedometer.

You are more likely to get swindled from Toyota than from mvpmotorsports.

 

Chris ( DIrEctQL ) Has that TRD LSD in his TT swapped SC, I didn't notice any difference at all...the only thing I noticed was hitting 120mph in a few hundred feet.

Look around online before hitting Toyota. I found my Torsen LSD (after almost buying a 6spd LSD) on ebay. Way cheaper than Toyota....((I'll let you know whats its like when I put it in this winter.)) Also check out the swap guy's online Jazz Pro Parts, TigerJapaneseEngines...they get that stuff all the time, and are pretty safe. But yes, nothing is safer than going to Toyota

 

The TRD LSD is much better for drag racing from a stop compared to the torsen lsd. Since you care about 0-60 times, just buy a trd lsd unit that can be installed in your sc400's differential housing (aka "pumpkin"). Twin turbo charging your sc400 is a waste of money given your goals. So, just put a supercharger on your car and upgrade the exhaust and you should be able to have ~5 second (or less) 0-60 times with excellent reliability and power band.

If you end up having traction problems after the supercharger, pay $700 for a traction control unit by RaceLogic...it will definitely make you accelerate a LOT faster and make the driving experience more safe overall.

 

At intellexual.net, "Be aware that mix matching...will alter your final drive ratio which will affect your speedometer accuracy."

This site claims that only the NA Supra Automatic LSD has the same drive ratio as the SC400. It claims that the TRD and all other Supra units have slightly different final drive ratios from the SC400.

(1) If I put an LSD unit with a different final drive ratio on my SC400, how will my speedometer accuracy be affected? Will it always be too high or too low? Will it vary between being too low or too high? I have never seen a car after an LSD transplant to know.

If I am going to do this LSD transplant, I would prefer to get something that is a certainty. If that means I have to go through a Toyota dealer or a motor sport company to get a new unit, then I am more than willing to do that. I tend to play decisions such as these more safely than anything. That is why I am asking so many questions.

**My main concern is about just how an LSD with a final drive ratio different from stock affects the speedometer. To the guys who have put a TRD LSD in their auto, how is the speedometer affected? Does this adversely affect the reading of other gauges as well?**

 

I have been running the Dragon torque converter...I first tried the KAAZ LSD differential and determined it was too agressive, too noisy, and needed way to much maintenance...I Then picked up a used 1995 Torsen Supra TT Auto differential...Slapped it on with no problems and have been happy ever since...Rides just like the stock lexus open end differentials except you always get the two wheel burnouts at lauch...

However, I have heard the TRD LSD is the best...I cannot comment on the TRD as I have not tried it out...

 

This is my exact plan: TC, LSD, Exhaust, Supercharger. I am glad to hear that my plan is consistent with my goals.

It sounds as if the TRD LSD is the unit for me.

My final question(s):
(!) If I order this product from a motor sports company (MVP having been suggested to me), what would be needed to complete the installation? Could I do the install myself? Would I need to purchase anything additional to the LSD unit itself for installation? Should I contract a local garage to do the install for me? Should I be asking the sales represenative at MVP these questions?

- Plus, can anyone tell me how badly the TRD LSD will affect my speedometer and in what way?

Thanks for everyone for the advice. This is an awesome forum-
Blizzy

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Note: I consider myself to be handy with tools, I have just never done much in the way of modifications to my cars (I am only a previous owner of a 1993 Taurus GL that had exactly zero things glamorous about it).