David_K

Have a wet nitrous kit wondering how big a shot i can safely run without melting the internals for the W58.

ki_soarer

hmmm, nitrous doesnt hurt the transmission. as for the motor, it will hold about a 100 shot safely. the trans will usually hold about 450-500 if you dont shift the hell out of it all the time.

David_K

Nitrous is hell on transmissions. Well on autos anyway. Smoked the tranny on my grand cherokee. anyways thanx for the info.

simann

Stock clutch and flywheel combo, probably around 300whp. The pressure plate is way to weak.

The W58's are pretty strongly built as well like the R154. Though people have had issues after running over 500whp on a consistant basis. Thats obviously with an upgraded clutch and flywheel (possibly driveshaft as well).

Though those figures can be miscombobulated due to mis-representation of how "hard" they are on their transmissions on a daily basis. A transmission that is shifted correctly will always last longer than one that is mis-shifted and abused.

Thats just the facts. Its a wear item.

-Jonathan

SCoupe

You should really "Search " and you will find more.

I'd give your w58 less than a month because you're likely to beat the hell out of it and the w58 is not that tough. Especially in a hard launch or 3rd gear torque roll on, they give it up.

The R154 is considered a desirable and known upgrade to the w58 as it will handle another 100+ whp. They are not equivalents.

simann

There are plenty of Mk3 supra owners running well in excess of 600whp (with nitrous to boot) and the tranny's are holding fine. Just make sure you get a nice sprung disc clutch assymbly and maintain the transmission oil.

There is one guy that drags his stock transmission/drivetrain 7m/R154 over 800whp on a weekly basis. Its holding just fine.

But again the rule of thumb is treat it like you would treat an old person in a wheelchair.

Once you get going, you can cruise really fast, but do not beat them up on the "launch".

ef9

I believe what breaks these trannies is shocking them. By that I mean going from no or very little load to applying LOTS of torque at once. That and shifting way too hard and fast. SCs are big heavy cars and once you start making lots of power the drivetrain is under lots of stress.

I've been driving mine around with 400+hp (15psi from a T67) for about 3 months now with no problems in sight. However, I don't launch it hard and I try to take it easy on the shifts. I think with these driving habits and at this boost level it will last as long as I want it to even with the 190,000+ miles on it.

I plan on trying 20psi soon though, so it may explode on me then. Time will tell. There is a guy on Supra forums with a NA-T Supra who made 550+hp through his W58 and kept it together for over two years.

As far as the tranny holding together while running nitrous, the only thing I would worry about is the nature of nitrous. Unless you're running some semi-sophisticated linear setup all that power is going to come on at once. Assuming you have some sticky tires and the car hooks you may run into some problems. I think an instant 100hp or so while the drivetrain is trying to move 3700+lbs may be too much.

I say try it and find out. It seems that most of the "knowledge" about the W58 that gets recycled over and over on CL and Supraforums is just people repeating the mantra of "300hp is fine, 400 is pushing it, 500 if you're ballsy, over that and it will give up" or something close to that. The number of people repeating what they've read is A LOT more than the number who have tried and broken W58s.

Cliffs: I think its all in how you drive it. Even the mighty V160 Getrag will give up if abused.

SCoupe

Has anyone ever run 600 RWHP through a w58 in an SC300 without shredding it?

ef9

A guy here in Knoxville made 640Whp through a W58. 1.5JZ, PT74, 272s, 22psi, etc. It held up for about 4 months before the 3rd gear syncro went.

Mind you, this tranny had the crap beaten out of it on a daily basis and before it was handling 640hp, it held 460 or so for about a year and a half all the while getting beat to death. Mind you in the end it had about 230,000 miles.

MJHSC400

So in other words a w58 could stand up to a lightly modded or even mildly boosted 1UZ if driven like you paid money for it--

That's good to know-- I think they make a bell for the 1UZ to mate to the w58-- much cheaper than a R154--- and the tailshaft will fit right where it needs to along with all the manual SC300 pieces working with it too-- with maybe a little modding on the tunnel--

simann

I would only option for the R154 with a V8. Thats alot more torque than the inline 6 could ever produce (HP vs. HP).

If you go ahead and spend the extra $300 for a used R154 you can save yourself a large headache with the W58. (selling your W58 for $200). R154's go for $500.

-Jonathan

MJHSC400

I'm not discounting your opinion, only arguing that the I6 is proven capable of 500/500 --- hp/tq-- so if the w58 can hold up to that for a few years of beating-- why couldn't it hold up to 400/400 from a mildly boosted 1UZ-- or even more likely an N/A 1UZ only making 300/320 pretty well modded--

It seems dellows feels that it can hold up to a v8-- they stated so in their literature, and they make a bell for the 1UZ to mate to the w58--

I'm just thinking along the lines that a manual with even zero mods to a 1UZ would be a huge improvement over the A340 in terms of performance-- That's all, I'm not talking about making 500 to the wheels here-- more like barely 350 max--

simann

V8's produce alot more torque at lower RPM than any inline 6 ever would. Basically the increases rotating assymbly mass is the contributer.

Turbo car torque curves usually start to increase at mid-high rpm levels (lag etc.).

You going to make alot more that 350whp on a midly boosted 1uz. Even though it may be only 350whp, it most likely will be 400wtq with the stock cam duration and lift. And that torque will come on quite quickly (probably around 2000rpm.).

I trust your opinion. Its your money not any of ours. You make the best decision for you. I am just telling you what I have seen in person and have read documentation reguarding these discussions about 1uz R154/W58 hybrids.

Wish you the best!

-Jonathan Mann

MJHSC400

Well, upon further thought and review of your seemingly expert opinion, the extra $300 would be well spent.

The only thing I hate is that if you want an R154 to fit, you either have to modify the tailshaft from an MA70 trans, or snag one from a soarer turbo--

Either could be costly-- and no doubt alot of these guys with even a 1JZ are spooling the turbo before they engage the clutch, so no doubt the trans is seeing some serious torque near 0 rpm (at the tranny)--

hemogoblin

I hope the w58 holds up. I have a bpu 2jzgte, and im driving it like a granny in hopes of keeping my w58 alive until I have cash for the v160.

All I have to say is, I had both trannys on the ground. And Im a big guy and I can pick up the w58 with one hand (maybe not, but very very light), and i can probably toss it 15 feet. The v160, is so heavy that I can barely lift it, it just feels like a monster.