IVE JUST STARTED MY FORGED RE-BUILD AND AM LOOKING AT ABOUT 350-400BHP AS THE END PRODUCT. SO CAN ANY OF YOU EXPERTS PM ME PLEASE WITH SOME INFO ON WHAT I WILL HAVE TO DO CONCERNING MY GEARBOX AS IVE BIN TOLD IT WONT LAST 2MINS WITH THAT SORT OF POWER.

MANY THANKS.

 

hi there, ive bin out of the scooby game for a while now, so things may have changed but i had a 93 wrx & it ran 320bhp & 341lbs. The gearboxes, did not last 2 minutes..... i went through 3 & 6 clutches......
I was informed that mine - plain old 93 wrx g.box it would hold about 290/300bhp at a push if in good condition & if driven nicely, no dropiing the clutch etc.. dont know how true that is, the figure may be less, im sure someone will give a better answer.
I learn't the hard way & twisted them gearboxes nicely lol!
From my past experiance, i am now back on the hunt for another classic import but looking at the sti v2/v3 depending on price & condition due to better internals as standard. (i also blew the big end bearings & bent a couple of conrods & nackered the crank from running this power aswell - dave at api sorted all me new parts out though!)

HTH's

Tim

 

thanks for the post mate.

So what exactly do i have to do then to make a gearbox survive 350-400BHP???

 

My V5 RA one lasted over 25 full drag launches with 397bhp and 372 lbs/ft with out missing a beat

 

i think i was looking at getting a newer type gearbox that could be a straight swap & could handle the power but at the time it was around the £2k mark.... so i just kept off the gas, sold the car to save for a house so cant really offer any good advice for what to do with your own, i was advised to get a better g.box rather than keep replacing a standard wrx one at about £600/£700 each time

 

It seems the subject it a bit hit and miss, well what gearbox from a newer or stronger scoob would go strait into my car then so i can look out for one ??

It the perfect time to get one and fit it as the engine is out, also i think im going to give in and get Neil at slow boy racing to re-build the engine as people keep on scaring me into how hard it is and how exact things have to be!!!!

This is understandable but i have done engines before however not jap.

 

You can stick a 6 speed STI box from a newage car into yours although you will need the prop and rear diff too I think. Have seen them going as a kit for £1750 upwards. Installation is fairly simple as it just fits straight in.

I am going to do the same to mine before I upgrrade the power.

As for the egnine I think if you are used to doig engine work there is nothing too scary about the EJ20 Subaru engine so I shouldn't get too apprehensive. Just do your research and you should be fine.

 

Mine went pop at 342BHP

 

You need to tell us what flavour classic you have - the early boxes were chocolate BUT the later ones would handle your level easily. STi5/P1 gearbox on mine was happy at 440bhp 380ft lb of torque - but swapped for a 6 speed to make it unbreakable should I get more silly with my car. if you have a ty 754 box you should be fine

 

WELL IM GOING TO HAND IT OVER IN A FEW WEEKS TO SLOW BOY RACING AS I KNOW IT WILL COME BACK GOOD AS NEW AND I'LL HAVE A PEACE OF MIND.

TO BE EXACT MINE IS A 1998 UK 2000 TURBO (R REG)

 

UK MY 98 had a TY752 box - sometimes Subaru fitted the MY99 box (the stronger TY754) but if they didn't then Neil is going to need to find you a stronger box

 

Yep 98 was the change over year. If it has a TY752 replace it. If it has a TY754 keep it.
Its torque that destroys boxes not bhp. So it all depends what torque figure you are aiming for.
Guessing with that kind of bhp a TY754 VN and an upgraded twin plate clutch should do the trick

Steve

 

nice one lads i'll make a note of those figures and find out what box it is.

Also as were on the subject....... how much is a 'twin plate' clutch and where can i get one from???

Thanks alot.

 

mine went crunch, scrape, squeek squeek (sounded liek the porr thing was crying bless it lol) at 280ftlb.

now on a ppg box

 

out of the classic boxes the v5 sti / p1 box were or are regarded as the strongest of them all, in saying that you will find some people will be running 400bhp in oldeer boxes with no issues and a v5 box will give up at 320bhp.

it is the same thing with the engines some std lumps will run 400bhp for 2 years with no signs of issues were another willl give up.

i ran my p1 for 2 years at 330bhp with no problems untill the clutch went last month (it was std) and i was told it would not last. just depends on how it is looked after and driven

what you have to work out is do you wnat to spend all that money on a rebuild just to drive 5 miles down the road and the box go bang, in all honesty you may as well do the box at the same time and have a reliable car which can take everything you throw at it, hencd why i ahd the p1 box changed to a sti 6 speed from a 04 plate so it is in place for a 2.5ltr when funds allow

best of luck in what ever you do