account2x

iTrader: (5)

The early supra r154s got the 3.909 ratio and later switched to 3.727.
The sc400 is 3.916 and supra twin turbo auto is 3.769.
The soarer got the 4.08 but it was a 1jz, less displacement and torque and higher revving than 2jz.

the mark 3 supra rear end if interchangeable only with the is300. the 2gs, 1sc and mark 4 supra differentials are interchangeable.

r154 and w58 gear is almost the same. So you want either the supra tt auto for longer gearing or sc400 for shorter gearing. Both are close to the way toyota wanted it from the factory with a 3l engine.

GS FONZy

iTrader: (6)

BAD954BOI

iTrader: (5)

wow... thanks for the corrections smh!!
but i like to break everything down sorry just a bad/good habit

1. even if i got the mk3 diff and gave it to a shop to make work in either the 4.08 or 4.27 at the end of the day i would be wasting my own time becasue it's impossible.. even if they tried to mod it.. right?

2. only options i can actually choose from that gets me a lsd and lower gears is either the 3.72 from the later mk3 or 3.76 from the auto tt mk4 right?

3. and am i correct with the whole comment about the 4.08 not being that big of a difference from the 4.27 or will the 4.08 give me everything i want short of the lsd issue?

account2x

iTrader: (5)

1) mk3 diff is only interchangible with is300. you want mk4 supra, other sc or gs
2) your only option for lower gearing and lsd is the 3.77(you round up here)
3) why bother even getting a 4.08, get the 3.92 from the sc400 since it's lower.

BAD954BOI

iTrader: (5)

the 3.92 would be perfect if it was LSD but with that type of gear ratio i'm about to say f*** the LSD because with the 3.92 i will jump on the guys with the 3.77 and it's low enough for me to keep up or keep the lead up top...

account2x

iTrader: (5)

u can put a kaaz lsd into the 3.92. I drive a lot on the highway so i favor lower gearing. either are upgrades imo

BAD954BOI

iTrader: (5)

according to: http://www.kaazusa.com/partinfo_japan.html
cant really make out the chart that wheel but all i know is it comes with a $1100 price tag

am i correct: open means its the 2 way lsd option?
and the torsen means it's the 1.5 lsd option?

account2x

iTrader: (5)

i think all torsen are 1.5 but clutch pack can be changed between 1.5 and 2.

1.5 is better for road racing
2 is better for drag racing

KahnBB6

iTrader: (5)

Really? I've read enough about the W58 in my car to consider that if I'm going to the expense of swapping in a GTE engine I might as well swap in an R154 while I'm at it. To each his own.

GS FONZy

iTrader: (6)

W58 are the weakes option to go with for sure. However, in the OP's case, this is just another excuse he's throwing outhere. I have a 1J with some BPU upgrades and a W58. Have not had any issues, since I'm not pushing huge numbers. A simple NA-t set up will not put you past or even close to the threshold of the W58. You'll need some engine upgrades before the W58 starts being an issue on NA-t set ups.

KahnBB6

iTrader: (5)

I am the OP. 1JZ's and NA-T setups do not pass Cali Enhanced Smog (visual). It's not another "excuse" on my part. If you live out here and have a way around the visual inspection or the potential roadside hood pop for whatever reason then you're a better man than I.

As for the W58 being durable enough for moderate boost setups? I'm sure it is but personally I will go with an R154 swap at that point.

GS FONZy

iTrader: (6)

I have yet to see a B.A.R. approved 2j swapped. Not saying that you can't do it, but lets just say I'm pretty sure it won't happen. Either way if your plan is to go 2jzgte, why waste your time with useless gears that are counter productive of your ultimate goal. You're right, to each his own, but I just think you're working backwerd or posting just for the hell of it.

KahnBB6

iTrader: (5)

That's mildly upsetting to me. I am not posting for the hell of it. What would the point of that be? I originally posted this to explore any alternative other than going NA-T or doing a GTE swap as a means of making the car even slightly less sluggish. I am not getting rid of my 4.08 pumpkin so whatever I do can be reversed very easily in my garage. To say I am just posting for the hell of it, though...

I tend to believe that too. I've talked to a couple of Cali guys with 2JZGTE swaps-- one with a JDM 2JZGTE and another with a USDM 2JZGTE. They would echo your sentiments on the likelihood of getting their swaps fully legalized no matter how "factory" (for a Supra at that) their engines may look but it certainly seems like a safer route to go with a stock looking 2JZGTE engine that has an OBD1 VIN on the block and an EGR port on the head. Not talking about ultimate potential here.

Because of that I am willing to try some slightly more aggressive gears in the short term. With them the car won't out accelerate an M3 or a 2011 V6 Mustang (ridiculous comparative examples have been used intentionally) and I'm not expecting that, nor do I care to race other cars on the street. I got over that years ago. I can change back to the 4.08 differential any time without much trouble.

Swapping out a whole engine and all it's wiring because of some smog related issue... that is a lot of trouble. The expense (other than the annoying cost of going fully USDM) of a swap isn't my issue. It's the legal unpredictability of what can happen with that swap when living in California that is my issue. Were it not for that I am certain that for the money a 1JZ would easily satisfy my modest power goals.

The gear change was originally intended to be done with a TT Auto diff install but based on the responses in this thread I will just try the 4.27 pumpkin first. If I don't like it and give up on my dogged desire to have firsthand experience, out it goes and in goes the 4.08.

kez

iTrader: (4)

i hate my auto diff now. in the beginning after the 5speed swap it was really fun but now since i drive up and down the highways it sucks cuz at 65 car is at 3000rpm. the gears are shorter and the car feels quick but honestly i would love to have a lower gear ratio

account2x

iTrader: (5)

A 2JZ-GTE swap out of a U.S. spec Supra engine is B.A.R. approved if the engine is the same model year or newer. All parts dealing with emissions need to be factory on the Supra or B.A.R. approved. It should be a very easy swap to get B.A.R. approved but why bother?

Get that SC400 diff. It's a direct swap.