Pelican Parts Forums - Found a Turbo S engine

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- Porsche 924/944/968 Technical Forum (http://forums.pelicanparts.com/porsche-924-944-968-technical-forum/)

- - Found a Turbo S engine (http://forums.pelicanparts.com/porsche-924-944-968-technical-forum/778904-found-turbo-s-engine.html)

I am not certain of it but I believe the rear pinion bearing is also larger in the turbo box. I don't think you can simply swap a turbo ring and pinion into a non turbo box.

Quote:

Originally Posted by AaronM (Post 7729691)

The differential in the Turbo transaxles is significantly stronger than in the NA transaxles. The ring and pinion is a weak point even at NA power levels and you absolutely need a turbo ring and pinion if you're going beyond NA power levels.

However, given that replacing the r&p in a 944 transaxle is a labor-intensive process and setting the lash is fiddly (plus the relative lack of availability of the r&p as a separate part) it's generally cheaper and easier to just get a turbo transaxle.

I would NOT use a 944 NA transaxle with a turbo engine. It's just asking to blow apart the ring and pinion.

how does the S2 tranny compare to these?

Here's a great thread on how to convert a 924S (same as an early 944, except for the lack of fender flares):

924Board.org :: View topic - My narrow 951 project

Basically, you'd be better off to find a donor car to get the necessary heat shields to install. The transaxle will and brakes will hold up for a little while at least. Just avoid dropping the clutch. Though the above thread shows the builder using his stock NA transaxle while drag racing. Considering the same basic transaxle in Audi 5000 guise is used for GT40 and Lamborghini replicas and 1000hp Audi 20V/AWD Audi's, I'd say that you'd be okay for a short time.

For the street, the turbo brakes aren't really any better than stock 944 brakes if they are in good shape. The turbo brakes do make a difference when you're using them to their absolute limits on the track, but on the street? Don't sweat it too much.

Focus on getting the necessary turbo heat shields, electrical wiring and ECU, etc. The rest can be done later after your wallet recovers.

The S2 transaxle is essentially the same as the Turbo transaxle just with a better gear ratio for the street, really wakes up the turbo cars, but at a hit to your fuel mileage :) Is a complete drop-in. Either way, make sure the transaxle fluid is changed, CV joints repacked and the linkage in good shape and adjusted properly while you're at it.

Many people break CV joints and transaxle cases due to failed engine transaxle mounts allowing too much movement when loaded. If you're planning on really wringing the car out with drag starts and the like, plan on moving to stiffer mounts to reduce the twisting that leads to broken CV joints and the like.

Quote:

Originally Posted by fiat22turbo (Post 7730662)

Many people break CV joints and transaxle cases due to failed engine transaxle mounts allowing too much movement when loaded. If you're planning on really wringing the car out with drag starts and the like, plan on moving to stiffer mounts to reduce the twisting that leads to broken CV joints and the like.

This can be dealt with by doing the semi-solid urethane mount trick and/or using a rod bolted from the back of the trans to the body to stop sway.

The late 944 trans mount banana-hammock is a really, really, silly design.