WRXSTU

iTrader: (1)

ok here we go.

my gearbox gave way back in febuary, so i decided to buy something a bit special.
i brought a 93 RA box and rear diff from an ex hill climb car(this car won the scottish hill climb championship last year)
i fitted the box and diff. i took the car out and within 500 yards i knew there was a problem with it.(kept popping out of 5th) but like a kid with a new toy i showed off with a friend in the car we pulled over and i launched the car at about 4000 revs the car took off like a rocket we did this once again and before the car had even spooled up properly there was an almighty bang it kind of sounded like someone was hitting the bottom of the car with a scaffold pole.(felt like it too) but seemed to drive fine if you didnt give it too much stick
so i took the box back out and sent it back to scotland to be re-built.
the box was gone for 3 months in total. after a month i brought a standard 93 wrx box just to get me back on the road.so i fitted the box and original diff. but i still had the problem with the banging from under the car.finally the 93 RA box came back and i fitted this and the diff that i had previously taken out.and i still had the problem with the banging.
i phoned a few people about it even took it to a few garages who suggested that it was diff wind caused by an incompatiable box and diff but this would have been the case with both, anyway i phoned the guy that i had brought both boxes from and he suggested that i had snapped a driveshaft and i would not be able to tell untill i took it out.i could not see any damage but the cv joint didnt feel right so i brought a second hand pair of driveshafts and cv joints from the local breakers at an extortionate price and fitted these.this cured the problem and i was over the moon...... untill tonight when i was on the way to a scooby meet. i pulled on to a roundabout with a tit in a BMW right up my ****. i put my toe down hard in second gear so as to loose him and sure enough there was an almighty bang again. i'm fairly certain that i have snapped exactly the same driveshaft at the CV joint.the only difference this time was that i had people in the back of the car.
is it possible that this 93 RA box just runs too much torque.
i dont think that my car is running too much power(approx 300 BHP).

does anyone know if it is possible to buy uprated driveshafts and CV joints or have any idea why this keeps happening.

the car is a 93 wrx fitted with leda coilovers,whiteline front and rear adjustable anti rollbars,whiteline adjustable rear control arms, anti lift kit and solid drop links all round.
any help or suggestions would be apprciated as i'm really sucked off.
sorry this went on a bit.

ustolemyname??stevieturbo

iTrader: (1)

STI shafts would be a bit heavier, but generally speaking, breakages are rare.

Are you sure you dont have a suspension alignment problem, putting stress on the shaft ?

Kenny.S

I'm no expert but it sounds a bit odd to me, the shafts are normally pretty tough on these cars, well at least at the power we're talking about here.

The drop gears in the box and the rear diff are definately matched? ie your not trying to turn the front and rear wheels at different speeds and getting huge amounts of wind up in the transmission to the point were something has to give?

Kenny

Tim W

iTrader: (1)

What front diff does the RA box have? Could it have been welded up for gravel rallying? If the front diff were welded up to lock the torque delivery to 50/50 each side regardless then it could be loading up horribly on cornering...where are the shafts shearing? Are they stripping the ball-race in the CV joint, shattering the cage?

911

Bit of a guess this:

It would be very unusual for a hill climb car to have a welded diff. The bends are far too tight and the previous driver would have had the same issues as you.
Is the car very low, ie lovered beyond 30mm from stock height?
With the extra passengers and the suspension deflection of the roundabout is the issue the drive shafts popping out of the front of the box (I assume the fronts are the problem). Do the CV's next to the box have their large dowl pins in place to lock the CV into the stub axles that come out of the box both sides?

If the front is too low the shafts are very displaced and the CV's can only give lateral or axial float to a certain ammount, about 10mm iirc. This float may be all taken up when lowering the car excessivly. Add the strain of even more deflecton as the car is cornered and something gives.
I expect it is only one shaft that's gone or both?

Graham.

WRXSTU

iTrader: (1)

graham i think you may be right.
it was the rear shaft that has broken.
i fitted the leda's myself and did not seem to have a problem with the height untill i had passengers in the back.
i've ordered some more second hand driveshafts and i'm going to fit them in the next few days.
then i think it's a trip to get the ride height and geometry set up done properly.
i spoke to you on here a few months ago when i was looking at gearbox options and you said you had a 93 RA in your car that you described as.... naughty
your right.....

911

Ahh, now I 'recognise' you!

If the car is too low the axial play will soon dissapear on the rear and the drive might pop out of it's indent clip in the diff.

The RA box for me was awful on a hill climb, far too much gearshifting when trying to steer/brake and so tiresome on the road with my small 16'' wheels.

Good luck with it all, and remember to let us all know how it works out. That's how we (especially me) learn!

Graham

WRXSTU

iTrader: (1)

changed the driveshafts tonight it's a bit too dark to see the damaged i caused but it was definately broke at the cv joint nearest the diff.

i cut the gaitor off to have a quick look and all the bearings fell out.
i've raised the suppension a bit all round (looks like a tank now) and will take it out for a drive tomorrow and see if this has helped.
thanks to all for your repplies.