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The mkiv Supra Owners Club

w58 transmission power rating


jdmjak

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Ok I can easily summarise this, because I've read it about 20 times lol.

 

One guy blew 3, on less than 360hp.

 

Listy had his BPU TT at around 400, blew his.

 

After I blew my a01a open diff, I snapped my INLET shaft at LOW RPM/speed with my NA-t.

 

Basically, if you go NA-t, it's on borrowed time and could last a week, or a year. Depends how you drive it.

 

300hp is probably the ONLY safe bhp. And that's still, borrowed time.

 

NA power up to 250hp is SAFE.

 

Some people have seen 500hp on here though. That's granny shifting, and not constant power/abuse.

 

Conclusion; if you go for power, NA-t or TT with a w58, KEEP an open diff to allow tyres to slip and not strain the box, and plan for the worst!

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do you know if theres anyway of strengthening or improving the w58?

 

I've looked into various mechanical strengthening processes, and hardening is one consideration, but then you can make the gears more brittle.

 

Sadly Toyota didn't design them with enough meat on, so your really limited. The internals just struggle to take any amount of stress.

 

The R154 for example has a stronger internal design, but a lot of the joining components and other parts aren't as capabile, which allows for gearbox upgrades. Sadly, the w58 doesn't have the bare bones to be upgraded.

 

Cost wise, your best off changing it out for a stronger box.

 

R154 conversion can be a pain in the ass, many haven't had problems, I personally did.

 

The V160 is by far the most cost effective route IF YOU FIT IT YOURSELF.

 

The cost to buy AND fit an R154 is about the same as buying a V160. So just do it that way (find some mates to help).

 

OR go auto, David P makes an awesome hybrid box which takes 500+.

 

Hardly anyone has these, which is a shame, because his efforts are clearly an engineering improvement on the current box with multiple coolers slapped on.

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damn, i was hoping you weren't going to say that lol the v160 is veeerrryyy expensive :( guess i will just have to be careful for now then.

my mate dazzi has just sorted himself a nice hybrid box he says its absolutely brilliant and capable of around 500 aswell if i remember rightly may have to look at this route if i can't source a cheap enough v160

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seems redline heavy shockproof oil can help a little bit, just had a browse on some forums and opie oils and it seems to have some good properties for keeping gearboxes in reasonably good health so im going give that a whirl and see what happens, cant make it any worse ;)

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Remember it's torque that kills boxes rather than HP.

 

As Noz said, I recently lunched mine (NA-TT BPU) and finding a replacement was an absolute nightmare.

If you are going to risk the box, make sure you either have a second one waiting, or are prepared to go R154 or Getrag, or have the Supra off the road for a while.

 

Supra boxes of all guises are becoming harder to get hold of.

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W58 suck. I remember my black one was running about 350hp I didn't dare push it any harder. Well I couldnt really as it kept blowing up clutches! A343/0E FTW! No expensive clutch repairs anymore :D

 

well im hoping i can run the w58 for a little while, i have a stage 4 clutch and lightened flywheel which i have bought over here in the states so hoping this will take some strain off the box.

been having a look into the hybrid auto today and after what i have seen and what you have said after fitting yours its definitely a possible route for me sometime in the future, its just sourcing the parts to get it done and swapping the transmissions out

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Not seen many do a manual to auto conversion. Can't imagine it'll be too hard. You'll need:

Auto engine harness and ecu

A343/0E Hybrid box

TT auto Flex plate

TT auto Torque Converter

TT auto Propshaft

TT Differential Flange

Auto shifter rod

Auto clocks?

Auto gear surround?

Auto transmission tunnel? Auto to Manual requires cutting not sure if it will work the other way round?

Possibly some extras ive missed

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hmm...maybe worth just holding off on that idea for now then and maybe just trying to get hold of a clean auto in exchange for my manual or something :/

im looking into fitting a bmw e39 m5 6spd box at the moment, need to get some more info but it looks like a fairly easy conversion but will need an adapter plate, clutch and fly, custom mount and propshaft

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