Strengthening a Transfer Box / Gearbox

[nuster100]

Appoligies if this has come up before (I did try running a search)

How do you go about stregnening a gearbox / transfer box to take increased power?


Im looking at an end target of 450bhp on my legnum, and wondered what sort of thing I can do the my new transfer box before I fit it to increase its chances of taking that sort of power??

Cheers in Advance


Jay

[Eurospec]

Auto or manual mate?

Cheers,

Ben.

[nuster100]

Gearbox is auto atm, but that could change depending on the limits of different parts.

In this for the long haul really, but dont really want to be replacing bits more than once, I'd rather strenghen things before their fitted if you get my drift.

Jay

[Turbo_Steve]

Most Auto owners (including the Evos) have fitted a transmission cooler and found this to be sufficient - even at fairly elevated power levels.
If you're serious about it, Thermostatic control and a fan is a good idea.

People have found specialists who will provide rebuild parts (seals and stuff) and re-valve it for more aggressive changes.

Manuals....dunno.....generally the Evo manual boxes seem to hang in there up to around 500bhp: it's more about the ECU map than the power in some respects: damage can often occur through shockloading due to boost coming in too hard.

This is especially bad on the earlier scoobs, where most gearbox problems seem to come from the casing itself twisting.

Transfer case...ahm.....no idea? Ben?

[bradc]

http://www.teamrip.com/TRE_EVOLUTION..._SERVICES.html

[nuster100]

Most Auto owners (including the Evos) have fitted a transmission cooler and found this to be sufficient - even at fairly elevated power levels.
If you're serious about it, Thermostatic control and a fan is a good idea.

People have found specialists who will provide rebuild parts (seals and stuff) and re-valve it for more aggressive changes.

Manuals....dunno.....generally the Evo manual boxes seem to hang in there up to around 500bhp: it's more about the ECU map than the power in some respects: damage can often occur through shockloading due to boost coming in too hard.

This is especially bad on the earlier scoobs, where most gearbox problems seem to come from the casing itself twisting.

Transfer case...ahm.....no idea? Ben?

So add a transmission cooler to aid the one in the Rad, or bypass the rad compleatly for the transmision oil??

Jay

[TAR]

The stock cooler tends to act as a temperature stabilizer, so I would leave it in place after the new cooler.

[stuey]

I thought someone said once on here at that sort of power the drive shafts may start to fail, as they do on the GTO's..

[Eurospec]

On the autos i find that sometimes the transmissions start to slip anywhere from 200 wheel horespower and above. That said ive seen them do 230 absolutely fine!

A lot comes down to the quality of transmission fluid used and how well it gets crap of the clutch plates etc.

I suspect, but i dont know, that the auto boxes will fail with big power- but thats just the feeling i get when i see them starting to slip i suppose.

Gear oil coolers definately help- install as Tar said i think is the best way.

The xfr box is the same as in an evo so in itself its pretty strong. I have evo customers with like 700 brake on stock xfr boxes, but if you drag launched it at that kind of power i bet they wont last that long! In a manual, i could see you mashing one if you give it lots of abuse. In an auto the torque loading will not be as sudden, so it will probably last better.

Cheers,

Ben.

[nuster100]

So would a racing torque converter or similar improve things for auto owners??

Jay

[Eurospec]

High stall torque converters do work, as does upgrading the springs in there, but i dont pretend to know the black magic by which they work!

Its a centrafuegal pump, thats about all i know!

And that hi stall t/cs are a bitch to drive normally with!

Cheers,

Ben.

[nuster100]

One of my friends has a 600bhp auto supra which has had the tourque converter done etc.

But im assuming supras are very tried and tested as opposed to our gearboxes.

Jay