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The mkiv Supra Owners Club

strengthen the w58


Noz

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Where I work we do a chemical process called SuperCase. would it be worth doing this to weak parts in the box to try and stregthen it?

 

This topic is a common one, but this process has not been considered as far as I'm aware.

 

Supercase is not like annealing and does not make the part more brittle.

 

Anyone else who is familiar with this process have any considerations on this?

 

And please don't say just buy a 6speed or r154.... if I can strengthen my box for NA-T for less than a few hundred quid I think its worth trying. The price will be this low due to being an internal employee, it may not even cost me anything, those the process is not generally this cheap and far more expensive.

 

Opinons please :)

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You would have to completely dismantle the transmission to this point before you could treat it so unless your a handy engineer with the Red Toyota manual or know a really good friend I cant see the process being free :p

 

image

 

The Achilles heal is the gears themselves. There just not beefy enough to handle huge torque so treating the gears is only putting off the inevitable for a little longer IMO.

Edited by Kirk (see edit history)
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SuperCase is an idea used in ferrule's in high pressure fittings. there is information out there, not sure where online.

 

a friend is trying to get hold of a dvd which should help more on the subject. the basic concept, is it treats the outside of the material, but not the inside. harding a component throughout will make it brittle, the supercase process increases toughness but keeps durability through having a ductile center, the same strength to that of the part before process.

 

the main idea for this was against corrosion, as 316 rusts badly unless treated (in given situations, we have salt fog testing you'd be surprised how rubbish 316 is at corrosion resistance when put to the test).

 

Martin, the process will be free i understand replacing parts may not be. i think it would be a SERIOUS pain in the donkey to try and get it apart. most people on here haven't claimed to have gear problems, mainly bearing issues?

 

if i could find someone to take it apart, and replace the components for me i would like to try this. if i get NO problems i think id be prepared to do the process again and see how far i can push it? brendens supercharged NA would be a good engine to put it to the test. though it would be design for failure.

Edited by Noz (see edit history)
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You would have to completely dismantle the transmission to this point before you could treat it so unless your a handy engineer with the Red Toyota manual or know a really good friend I cant see the process being free :p

 

http://i26.photobucket.com/albums/c123/cul8r2fast4u/IMG_0701.jpg

 

The Achilles heal is the gears themselves. There just not beefy enough to handle huge torque so treating the gears is only putting off the inevitable for a little longer IMO.

 

That picture just made me heave a little!

 

@ Noz

 

Sorry I never replied to your PM buddy, I completely forgot to do so after I did a bit of looking into your process and then got side tracked!

 

I really don't think there is one particular thing you can do to the W58 that is going to cure its weaknesses because they can fail in several different areas.

 

The old reliables of synchros, bearings and seals are all replaceable and there is nothing you can do to improve on the original design as far as I can tell so just buy the best.

 

The geared components themselves, the gears and the shafts, are the main concern. But from looking at my own I'd say that they are just inadequately sized to handle alot of torque and, in some areas, thrust. I doubt a case hardening process will make up for a lack of material in the long run as it's not usually as a result of gradual wear that the boxes fail IMO.

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Martin, the process will be free i understand replacing parts may not be. i think it would be a SERIOUS pain in the donkey to try and get it apart. most people on here haven't claimed to have gear problems, mainly bearing issues?

 

It is a serious pain in the arse to do trust me ;).

 

Bearing issues are more a wear and tear thing IMO although i wont rule out some failures were down to accelerated wear from stress on the original bearings.

 

When paired with a TT engine that produces twice the torque the box is rated to then your asking for trouble as I and Damien said the gears are not substantial enough to take the torque they will be subjected to. Dr Doom found that out the hard way. He's gone through more W58's than anyone else and I dread to think what the insides looked like. Point being subjected to abuse after a short while they will grenade themselves.

Edited by Kirk (see edit history)
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DEFINITELY not worth it, some boxes have a large over torque capacity, some don't. The W58 doesn't like shock loads or much more torque than stock. Period. Micro polish, cryogenically treat stuff, use fancy oils, do what you want, but it's gear width and gear centres that need changing, which is impossible.

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As Martin and others have said, it's not worth the time and effort unfortunatley. If you're putting 400ish+ bhp through it then it's a ticking time bomb as to how long it will last. I destroyed two W58's and bought a third before i came to my senses and realised i needed a 6spd Getrag to cope with BPU. If i'd done it in the first place i would have a fair bit of cash. I also chewed up 3 (or possibly 4) NA open diffs, before i realised i needed a TT Torsen diff :rolleyes:

 

If you can get the treatment done cheaply enough (inc gearbox dissassmbly etc) then it'd be interesting to give it a go. If it's going to cost £££ then i'd give it a miss! ;)

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  • 2 weeks later...

not sure on the cost, thing is im not 100% on what to get treated. if i knew what the weakest parts were id definitley look into it.

 

thing is, i dont think anyones totally sure on the `weakest` parts, as they are so many.

 

anyone got an idea on a bullet point list for weakest to strongest of the gearbox internals, i would probably try and do as many as possible.

 

i know some people have had no issues with BPU levels on a w58, it must be due to how the box is used before conversion.

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