KahnBB6

iTrader: (5)

I've searched for something definite on this but all threads relating to the W58's inherent weaknesses are focused on boost applications.

What I want to know is if a TT Auto LSD rear end is going to over-stress and within short time blow my stock higher mileage W58 5-speed on completely stock 2JZ-GE engine power.

Since the NA MKIV Supra 5-speeds had an LSD option for a few years it must be safe to do this. Can anyone confirm this for the SC? Have Supra NA 5-speed guys ever blown their W58's on non-turbo power in normal/spirited driving?

outlaw0209

Dude, an lsd wont do any damage to your tranny. ESPECIALLY a torsen. That is exactly my set up, the stock w58 and auto torsen and I track my car and beat the living crap out of it. In my opinion, the life of the w58 depends on your clutch more than anything and how you drive it.

KahnBB6

iTrader: (5)

Thank you! That's a load off. I was thinking it was necessary to run an R154 to stay reliable. By the choice of clutch you mean anything above a full-face single-plate clutch, right? Mine is just an ACT Stage 2.

outlaw0209

As long as it's a good and proven clutch. Main thing is that it shouldn't be too aggressive. You'll be more then okay with your set up. Start worrying about it when you have 400 horsepower. Even then, it should still last you a good amount of time if you drive it properly.

KahnBB6

iTrader: (5)

Thank you. Where I live I won't be getting anywhere near 400HP any time soon without a lot of money (USDM GTE everything) so I just want to focus on the suspension, brakes and driveline. If you're enjoying your W58 car with a Torsen LSD that's good enough for me. If I ever get around to an engine swap the transmission will be changed with it. Until then, I'd just like some added all around traction with the stock trans.

account2x

iTrader: (5)

The W58 was first released in the early 80s Mark 2 Supra. That car was rated at the torque your car dynos at the wheels. A LSD won't blow your W58 but spirited driving can.

KahnBB6

iTrader: (5)

Well in that case, how spirited are we talking? I don't drop-launch the car or drag it and I don't slam gears or try shifting it too quickly especially if I rev the engine to 6000rpm for acceleration... but I do drive "spiritedly". Sometimes I'll drive on Mulholland Drive spiritedly but usually no more than the speed limit. To date I haven't and very likely never will drift this car. I just enjoy driving it. I don't think what I do can be considered abuse for the W58 transmission but if any of this sounds like it is, I'd like to know. That would mean I have to source and set aside an R154 conversion just to stay reliable.

I thought it was the shock-load generated from turbo applications that is what usually overcomes the stock 5-speed.

I realize there are one or two threads already covering the W58's weaknesses but from what I'd painstakingly gleaned in those, not abusing the transmission by doing drop-clutch launches or shifting too hard and fast at higher rpms -- as well as staying away from turbocharging -- would deem the W58 safe to use and enjoy.

Am I close to the mark here or far from it? I'd appreciate your input because that would influence me to not spend money on a TT Auto LSD and instead just plan to collect an R154 trans conversion for when my W58 blows up on stock power.

These things have been talked about a lot but there really is nothing definitive on W58's.

account2x

iTrader: (5)

Yes

But you do realize the TT AUTO LSD DIFF has a different gear ratio than your stock differential. Your speedometer will be off and it will make your car slower off the line because it puts more load on your engine but your 5th gear cruising mpg would increase.

The R154 and the TT AUTO LSD is a good combination for a turbo vehicle.

QwkSC

iTrader: (1)

I dont think a TT LSD with W58 swap vs 4-speed auto open diff will have taller gears. I think the w58 has shorter gears than the 4-speed so it would make up for the TT's longer final drive. Combined with the extra power to the wheels from the manual swap and it should be faster. Right?

account2x

iTrader: (5)

^What?

KahnBB6 has a factory 5 speed, it has a 4.083:1 ratio differential. The TT AUTO is 3.769:1.

outlaw0209

Correct

Also, the speedo won't be off.

BartleDoo

iTrader: (1)

The W58 should not blow on a stock ge.

outlaw0209

You'll be fine man. I drift my car and clutch kick the living crap out of it at every event once a month for the past year and some change. Transmission is smooth as can be. 180hp won't do damage to your transmission.

KahnBB6

iTrader: (5)

I've caught up since last night. Thank you guys. I went through the same dilemma about buying/not buying a used WRX or Legacy GT 5-speed over their transmissions.

Regarding the rear axle ratio, I am aware that swapping in the whole TT Auto pumpkin will cause my speedo to be inaccurate and give my car less aggressive gearing. I already plan to go to the extra expense to take it to a reputable shop that has experience setting up LSDs and swap the TT diff onto my 4.08 ring gear and pumpkin. I'd probably just keep the 3.76 ratio set aside. It's not certain to me when/if I will get to do a full GTE and R154 swap so I'd rather spend the extra money to keep the original ratio.

Thank you guys. I'm convinced I'm pretty well set as long as I don't go into any truly abusive driving situations or boost the car on the W58. It is at 194k.

account2x

iTrader: (5)

I would take the loss in aggression for the drop in RPMs.