T56 Conversion on a R33 GTST

[RNS11Z]

I have the oppurtunity to get a Holden T56 6speed Box from a VX Clubsport R8 for a really good price (Under 1k). Just wondering has any one heard or performed this conversion before? What difficulties would i also be looking into ie. Would i need a custom bell housing or so? I know the tail shaft and gearbox cross member will need to be modded and so will my clutch. Any information would be much appreciated.

Thanks

Harun

[Cubes]

The question is really why you would want to do that when the 25t box will handle 700hp?

You would be better off ripping out the 25t box your self and getting it reco'd if yours has the typical syncro grabby/crunch feeling.

I can feel the heat from that VX Clubby gearbox from here.. :uh-huh:

[R34GTT-R]

:microwave sounds a little :flamed:

Contact Rod Hadfield at Castlemaine rod shop if you still interested he can supply you the whole conversion kit.

[KamikazeR33]

25t box is way better dude

for that price and also the price for the conversion kit ur box could be reco'd to handle shietloads more power

[RNS11Z]

Theres nothing wrong with my box. Its all good. Just short 1 gear (no sixth) my car maxes out between 240-250kmh. I run out of gears and revs. So im sort of in the look out for a 6 speed. I know the Rb25 boxes are good and strong though i wish it were a 6 speed!

[Kdawgboostin33]

Dude,

Have a look at GCG Turbos they have some 6 speed Sequential Gearboxes there for around 3K which would be a very sweet investment

[Nismodified]

the 6th speed in the commo box is there for fuel economy reasons.

Please do not go ahead with this conversion.

[Rezz]

Originally posted by Nismodified

the 6th speed in the commo box is there for fuel economy reasons.

Please do not go ahead with this conversion.

I agree. It`s a 5-Speed box with a 6th speed added for better economy at cruise, which, incidently, is still shite...

[JimX]

I think the biggest problem aside from the conversion hassles and cost is you'll have is more drivetrain loss through the bigger box.

Maybe you should try selling the box and doing one of the other suggestions. You should make a profit on it easy.

[JimX]

Originally posted by Kdawgboostin33

Dude,

         Have a look at GCG Turbos they have some 6 speed Sequential Gearboxes there for around 3K which would be a very sweet investment

I had a look on GCG and the only thing I could find was a sequential shift conversion kit (no box) and it is only 5 speed

[slip]

Dude, just put a taller diff ratio in. Easy. Youll also be able to hold a gear longer which can help in mountains/track driving.

The 6 speed commodore boxes do not get a good rap in drive tests. Bad idea.

[Guest RedLineGTR]

why not a gtr r34 gearbox..eh hehehe

[esprit]

Just go all out and buy a Trust 6-speed dog box

[RadiuM]

agreed, like everyone else says..

the commo 6th gear is just a lower ratio for better fuel economy. It's really a 5sp but with 2 overdrives. In theory if the commie had enough power and could redline 6th it could get to 450+ odd km/h

Shaun

[JimX]

I can fully appreciate getting something cheap and wanting to fit it even though it's not really the best thing to do. I've done it before and I'll probably do it again

This thread has been pretty useful. I had thought of fitting a Commodore 6 speed before as well, but now I've scrapped that idea due the hassles and people saying it's not a very good box.

I also since learned that the RB25 box was a lot stronger than I first thought, because according to SydneyKid they use the same quality gears as GTRs (therefore good for ~700hp like Joel says).

One of the reasons I thought of upgrading was because I thought the RB25 box might be too weak for anything over 300kw so (in fact some people told me this), and since the GTS Commodore had 300kw the box must be good for more than that. I was way wrong and I'm glad, saved me lots of money

I'm happy with my RB25 5 speed (does it have an actual name?). If I want more top-end I'll go the diff ratio change.

Edit: Btw, I do know that gearboxes are rated to torque and not power. It's just hard for me to wrap my head around how much torque an RB25 engine is putting out at 300kw or 700hp so I've used those terms above.

[slip]

Wouldnt a supra box be a better option if you wanted a 6 speed?

changing gearboxes to get higher top speed is like doing surgery when all thats required is a band aid (diff ratio change)

[Nismodified]

6 speed supra box sounds like a good idea, ive heard (could be wrong info) that its box had quite short gears in it. I found that strange since i expected a broad torque spread on supra TT's.

[slip]

Well it could have short gears, and use a tall diff gear.

[RNS11Z]

Alot of good information here guys. Much appreciated. In that case what would be a good 6 speed conversion? I dont have 20gz to spend on a Hollinger 6 speed either. Something under 5gz. If that gearbox for sale from GCG is for 3k, the 6 speed sequential, then that would be a grab but i find it hard to believe. How much is a supra 6 speed going for these days?

[Cubes]

Have you thought about getting your box rebuilt with different ratios.. It was mentioned who did it and how much a while ago on this forum