WHATS THE BRAKING POINT OF IMPREZA GEAR BOX ?

[RASTIVL]

HI THERE ,I HAVE A 99 STI RA WITH THE CLOSE 5 SPEED GEAR BOX , DOES ANYONE KNOW WHAT THE MAX NM AND BHP WOULD BE TO KEEP THE THING IN ONE PIECE , THANKS

[Scoobman]

Check the code (plate on side of engine bay)
On that year I am pretty certain it will be the stronger
TY754 casing.
Its torque that destroys the box - not bhp
I know someone that ran 370 bhp through one of these boxes with no probs.
I have run 300 bhp and 340lbs through one
And also 350bhp through one

So south of 400bhp. Over 350bhp your are risking it.
Torque - well the best I can do is 340lbs - It held fine
I guess At one point it was running closer to 400lbs

Hopefully this gives you some pointers

Edited by Scoobman on Saturday 24th October 19:58

[Gnits]

With any luck I should be running about 360bhp and about the same in torque through a 98 STI RA box soon in my Murtaya. Will see how it goes!

[Scoobman]

You should be OK with that - over 350 and the odds of it going gradually pick up

[Vixpy1]

2nd or 3rd will go bang over 350/360 ft/lbs on a 2 Litre, fit a 2.5 and it will break very quickly indeed.

[RASTIVL]

THANKS GUYS , I THINK I WILL TRY AND GET IT MAPPED FOR UNDER THE 400HP MARK FOR NOW , UNTILL I HAVE THE SPONDOOLYS FOR A NEW SET OF DIFFS AND GEAR BOX ECT ECT, THANKS FOR THE HELP

[deviant]

It would also depend on how its driven and maintained. Quickest way to kill a gearbox is to do a few full bore launches and ignore doing oil changes.

[ScoobieWRX]

If you love to abuse your 5spd gearbox and worry it will go bang sometime soon, kill it first before you get another box (just like i did, demolished 3rd after a huge amount of abuse for a long time). Fill your replacement box with Redline Heavy Shockproof while your new box is still in fine fettle and enjoy many miles of trouble free gearbox motoring.

Works for me

[Marko21]

When I was getting my WRX remapped at TSL a guy there had a custom engine put in a 1998 sti, was running close to 500BHP on a standard gearbox. Gerry didnt seem to bothered although they were trying to source the gearbox from a Dogde Viper to go in it as the next stage was the 600bhp mark.

I think the Litchfield Type 25 Impreza, with the Cosworth engine, runs with a standard gearbox and thats running 405BHP and 415ft/lb of torque.

Hope this helps

[JollyGrnMonster]

as has been said 350bhp/350lb
iirc 383bhp and 383lb broke 3rd on dyno..
sometimes with the right oil they last longer than a few full throttles lol

type 25 has a newage 6speed.. run over 600 through one without issue..

Simon

[Gnits]

Ended up with 370bhp and 395lb/ft - PROPER monster now.
Ummm...
Don't have 2nd gear anymore though, it ate itself.
New gearbox required sooner than anticipated but it was a 12 yr old box so not un-expected.

[ScoobieWRX]

Gnits said:

Ended up with 370bhp and 395lb/ft - PROPER monster now.
Ummm...
Don't have 2nd gear anymore though, it ate itself.
New gearbox required sooner than anticipated but it was a 12 yr old box so not un-expected.

Get the 6spd conversion or PPG your 5spd. All synchro dog box with straight cut 1+2, Helical 3+4 and std 5th. Should be awesome!!

[Gnits]

WR1 box comming right up!

[ScoobieWRX]

Gnits said:

WR1 box comming right up!

That'll do nicely