morris

iTrader: (2)

Okay time for a new tranny for the GS400. My last tranny was a supposedly built transmission and good for supposedly 800hp. Well short story is, it wasnt.

So somebody tell me what options I have here.

I need to handle up to 800 hp or so

I have been told by several people that the GS tranny due to design limitations cant really be built to handle that much hp no matter what is done to it.

Supra tranny is very costly and untried, I dont really want to be the guinea pig on a 6K project

R154 isnt going to handle the hp even if I could get it to fit.

any other ideas?

DaveGS4

iTrader: (2)

I'd start doing research on a TH400 tranny were I you.

Oh, and sorry to hear about the prior one

morris

iTrader: (2)

Yea it happenede on the way back from MD.

Do you know anyone that has succesfully made a TH400 fit and work in the GS?
Sources for bellhousings etc?

From what I have read on other sites the TH400 will want to rev kind of high on freeway driving, but I may be at the point where I am wililng to live with it.

DaveGS4

iTrader: (2)

I believe SRT did it for at least one (maybe two) of their TT GS400's. I read Mitch was running one. Don't know the details, but definitely worth a call to Mo or PM to Tturbopimp or others to check.

May also want to see what some of the high HP FI IS300s are running.

ksu1998

iTrader: (1)

Dave is right, I have read about a TH-400 was used. Have seen it on a 2jz with 800hp...the last TH-400 I messed with was on a pontiac 400ci ..crazy...

http://www.turbo6.net/

D

Supraownzu

iTrader: (1)

Ive seen built th400's on 2jz's, actually getting to be pretty common. however to do it right will cost a good chunk of change. Quite a few places sell kits to mate the th400 to a 2jz, dont know what it would take to do for a gs400, as i'm not very familiar with the motor. I know SP has a kit for the TH400, and also Boost logic IIRC. The kit i saw, was custom built to take care of a few short comings of the commercially available kits.

after i kill my built supra auto, i plan to switch over to the th400 or a 4l80e.

GSteg

iTrader: (15)

I think the GS300 and GS400 uses the same transmission. That's as far as i know

JBrady

Well, if it were me... I would strongly look into a GM 4L80e which is basically a THM400 with overdrive and electronic valve body.

http://www.hotrod.com/techarticles/g...ission_review/

It would not be cheap but ultimately the strongest choice with overdrive.

A less strong alternative would be the Toyota/Lexus 4 speed automatics which are at least stronger than the 5 speeds but have mixed reviews handling mid level powered Supras.

morris

iTrader: (2)

Yea but has anyone done it in a GS, or do I get to be the guiniea pig again.

JPI Racing

Hey Morris,
I personally have the Th400 on my race car. Our tranny is fully built and could go up to 1500whp. You would have to make an adaptor plate for mate up with the engine. Custom driveshaft have to be in place. Custom tranny mount and brackets.
Here are the Pros: If built right, it would be the last tranny to have to replace. Down shift to first gear at 60 mph. Did I say it's a bad bad tranny?
Cons: You have to shift manually. Yup, We have a B&M ratchet shifter(This unit is about $150 from jegs.com), cruising on the freeway 60mph at 35rpm , Convert the signal from tailshaft so it would register on your speedo. Expect to see some power drop by using this tranny.
PS: The tranny tunner need to modify a little to make a perfect fit. It would be a tight tight fit.
JPI

Hameed

It would be cheaper if you just dumped the GS400 and bought an S65 AMG that handles that much HP from the factory.

Just messing with you bro!

c0wboy

This is the crux with the GS. Not many people are interested in performance so innovations are slow coming. Overall there's only 4 real choices for what youre' trying to do.

Th400

.....Pros- Very strong if built right.

.....Cons- Pricey if built right, and there's a lot of parts that go with it. As JPI pointed out, 60mph will get you 3500rpm so highway cruising is out. 25%-30% power loss through the trnas. The 4l80 is an option however the trans is massive even for the MKIV Supra, and even though Supra guys are all about performance, we have yet to showcase one daily driven 4l80.

V160

.....Pros- The last trans you'll ever need. Smooth shifting, great highway trans. No more luxo-barge, but a huge step towards true enthusiast performance car. More power to the rear wheels than the stock Lexus trans

.....Cons- May require some engineering to adapt to the GS, roughly 6K for a swap.

R154

.....Pros- Same as the V160, less expensive entry cost for trans

.....Cons- Same as the V160, less powerful transmission all together. Shifts like it's out of a truck because it came out of a truck.

Built Toyota Auto

.....Pros- Lower cost, direct wire in, full compatability

.....Cons- Roll the dice and take your chances.

That's about it for the choices.

Thanks man,

Eric

morris

iTrader: (2)

sucks to be me, over 20K in engine work and no way to get it to the ground.

Supraownzu

iTrader: (1)

welcome to the club. you can buy overdrive adapters for the th400 that will allow it to be used on the freeway, i foreget what they call them though.

c0wboy

It's the Gear Vendors overdrive unit. Expect to pay another 4K for the overdrive unit by itself, and then it carries mixed reviews. There have been vibration problems reported.

Eric