Keeping a Transaxle in one piece with high torque engine - Alfa Romeo Forum
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Keeping a Transaxle in one piece with high torque engine

Have a friend who is trying to sort out a transaxle for his race car.
See his post from another forum below, hope you guys have some info.

I am trying to decide whether to work around the Alfetta transaxle or toss it and cough up stupid money for an aftermarket transaxle.

My goal: I aim to make close to 550Nm or torque from a two liter engine on 50psi boost. So, 550Nm gives most transaxles a hard time.

I am reasonably clear on what the options are outside of Alfa transaxle, so more interested in what can/has been done on Alfa trasaxles and whether anyone has been able to get them to hold together. It is feasible that I can torque limit via the computer to try and limit torque due to impact shocks to the trans. The wheels are the fuse to a certain extent, but I do intend to run slicks on the car, and call me crazy, but I do want to be able to do a hard launch off the line and not have to worry about picking up the pieces.

I've heard many a rumour, but none confirmed...what did Beninca put behind their turbo'd green Alfetta from the 80's?. Was it a transalxe, if so was it alfa? I had heard it might be Hewland and not transaxle...again not confirmed. I am particularly interested if they ran Alfa (I doubt it) as this means there may be hope.

Things I know can be done to the transaxle:
straight cut gears
steel gearbox end plates )not seen it done on Alfetta)
oil sprays and oil cooler
outboard brakes (I guess would pee more heat out of diff/oil
A less agressive clutch material..athough tricky given the torque target
stronger cast clutch bell housing.
shifter mechanism moved inside the casing
has anyone installed an aftermarket lsd into an Alfetta...I've heard rumours yes
install a bracing frame tieing clutch housing to box and diff (in alloy I guess to avoid expansion issues)
Crown wheel and pinion...will the talest ratio still sheer teeth and if so, is it due to week diff mousing or week teeth?
Has anyone priced a new pinion and crown wheel shaft?
....Which unit to use, Potenziata? Are there decent ratios in Potenziata? I know they have 4 sun gears instead of two in the lsd.

I expect one could spend 15-20k easily on an Alfetta box..which I would be ok to do if I thought it would ever hold together. Aftermarket options installed can easily get to 50k....take a Hewland LS box...its almost this just to buy (but at least you get clutch,box and diff in the right order!)

The easy answer is no, it's not doable, we all know of people who break the box's, but it is typically not from engine power alone, it is a combination of engine torque plus a shock loading of some sort.

If anyone has suggestions of people I should contact, or thoughts on the topic, I'm all ears.
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I am no expert on this but from what I remember the issues relate to the propshaft rotating at engine speed and limits of the transaxle itself - they are not designed for that level of torque.

KevinGTV knows quite a bit about this from the racing Alfas in South Africa where one of the combinations used was the Getrag gearbox from one of the BMW M cars mounted up front linked to a (albeit quite heavy) rear diff from the Alfa Sei (119 series) which was RWD - finding one of the those diffs will not be that easy and Kevin would be the best person to help advise and track down the bellhousing adapter required for that conversion if you went down that route.

obviously there are other solutions but either way, it is going to be expensive!
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