supra 6 speed conversion

[1jzracing]

what will fit and what is different when changing a w57/8 to a Getrag 6 speed

input and output shaft?
overall length?
shifter position?
etc.

also looking for a 6 speed to buy if anyone knows of one for sale

cheers

[ill-minded]

have you tried asking norbie yet?

i think he'd be pretty knowledgeable in this area given that he's almost done swapping a getrag into his MA61.

[JustenGT8]

Everything is different and a heap bigger too.....check out Norbie's grey hair as proof.

Oh yeah, he might have some tips too

[1jzracing]

yea been doing a little research

its for a race car so nothing is too big a problem
looks like a new pair of plates for my clutch and a new coupling instead of the uni on the front of the tailshaft is the major bits

all i need is to find someone selling one

[JustenGT8]

Plus the funky hydraulic thrust bearing setup they use...will prob require new pressure plate to suit?

For the dollars it will cost you a custom PPG gearset for the W58 (or R154??) is probably a better option? or dare i say a Tremec? These things are so cheap in the US it makes me cry having bought one locally. The TKO600 is twice as strong as the getrag but only 5 speed. Anyways, just some thoughts.

[1jzracing]

yea been through all those options, im on about my 4th w57 square cut c/r gear set now and im sick of it!!

the box just isnt physically big enough to get the strength in the gears, not strong enough for the traction and hp considering its close to 600 now (std box does about 3 laps)

I did a whole season on the last one befor 3rd let go which is a credit to it really considering the punishment

the other problem is the likes of tremec have crap ratios and once i buy the box and get a c/r gear set etc then i wont get much change from 10g plus i have to adapt onto the block etc

the v160/161 are essentailly an M3 box and are BIG and strong as hell
will bolt straight on to the block, converting to push clutch for the tilton is no problem and the ratios are nice and close, ignore 1st and they are similar to what i have now, they go for around 3g

so i recon it makes the most sence

open to all options though

[Norbie]

what will fit and what is different when changing a w57/8 to a Getrag 6 speed

input and output shaft?
overall length?
shifter position?

Input shaft is totally different (massive and chunky), there is NO output shaft, it uses a 4-bolt flange instead. I have photos on my web site if you want to have a look.

Overall length is actually pretty much the same (ignoring the shifter), it's the width and height which are significantly larger. It's mostly the rear section of the box which is significantly bigger - the W5x boxes taper in towards the back, but the V160 is pretty much the same size right to the back.

Shifter is external so position is very different to a W5x with internal shifter, but more or less the same as a W58 with external shifter (eg JZA80 Supra box), so it may or may not be an issue depending which type of shifter you're using now.

also looking for a 6 speed to buy if anyone knows of one for sale

They don't pop up for sale very often, usually you need to get in contact with an importer and ask them to get one in for you. Aaron from Rampant Performance Imports gets them in fairly frequently so maybe try contacting him.

[JustCallMeOrlando]

Sorry to interrupt but where in the states would be best to get the TKO Justen?

[MR 1JZ]

dude if you are breaking straight cuts in one session then is a getrag gonna last much longer? justifying the $3000 outlay?

[JustenGT8]

Sorry to interrupt but where in the states would be best to get the TKO Justen?

Ebay mate New boxes going for a song....just need to get them back to Oz. Jack, AKA 3SGTE TA22, just got one back with the help from another toymodder so maybe drop him a PM.

[JustenGT8]

dude if you are breaking straight cuts in one session then is a getrag gonna last much longer? justifying the $3000 outlay?

I would have this nagging doubt too. The Getrag box is also known for losing 3rd gear, syncro goes 1st then the gearset. Could just be from abusive drivers so if you have a nice shifting technique then could be find....as you know the track will find a weakness if it's there.

I find the tremec ratios great for the big torque turbo..long in gear accel is quicker than constant cog swapping with my flat torque curve. Your 1J (?) is a bit peakier i guess ???

As strong as the getrag is the Tremec is literally twice as strong (well nearly) rated at 600ftlbs versus 350ftlbs for the getrag.

Does sound as easier proposition for you, just playing a bit of devils advocate. Plus i get to say i told you so if you break it

[JustCallMeOrlando]

Happy times. Cheers for that dude.

[MR 1JZ]

justen...if he is busting straight cuts then id say that 1JZracing isnt exactly nice on the box...cant say I blame him though...its a racecar...its meant to be driven hard

[Norbie]

The Getrag isn't the strongest box in the world but there's no doubt it's a great deal stronger than any W5x, straight-cut gears or no. The physical size of the gearset is what makes the difference here; bigger gears = stronger box.

Whether or not it's strong enough for the intended application is another story, although I do know of several very big power Supras which have copped years of abuse on the street and the track and their gearboxes are still going strong.

[JustenGT8]

That straight cut gears are stronger than normal gears is one of the biggest myths out there. An equivalent helical gear set is stronger than a straight cut gear set, with something like 1.5 times the contact patch.

And therein lies the advantage of a straight cut gear. With less contact patch there's less friction and therefore less drivetrain loss. In a world where 10th's of a sec count this is significant.

the straight cut gear also allows for quicker shifts using the dog engagement rather than syncros.

Where a straight cut gear can be stronger is where the replacement of the helical gear allows for a physically bigger gear to be used or in a custom box where they can make the gears any size they want.

As for this swap...one of those suck it an see jobs i think. Good oil with regular swaps will be essential and i'd look at a tranny cooler as well just to be sure....at the very least monitor gear oil temp for a few meets to see what it's doing.