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G50 vs other Porsche Transaxle
geoffreyh - 22/6/05 at 01:03 PM

Hi,

I'm looking for transaxles for my project and should find a solution that works with 300+hp from a chevy engine.

Most of the information I find is about the Porsche G50 or one of the ZF transaxles.
Those are quite difficult to find and I'm wondering why I can't find information about the use of other Porsche transaxles.

Or can I use an Audi Transaxle for example. Are they strong enough?

Cheers,

Geoff


NS Dev - 22/6/05 at 02:07 PM

No, the Porsche is the only transaxle which will reliably cope with over 300hp.

In fact they will take a lot more!!

The alternatives are basically the very expensive hewland and ZF's which are megabucks.

My mate runs Ultima Sports and their current demo car has a 641hp, 550 ish lbft 6.3 ltr chevy in it and it runs a std porsche G50 with no problems.

You are looking at around £1500 for a decent G50 as a ball park figure.

The alternatives generally mean one more "0" on the end of that figure!

Incidentally, you don't want to hang about on this one as new G50's are no longer available (think my mate bought pretty much all of them!!) only the 6 speed Getrag from the newer porsches, so s/h prices for G50's will start to go up from now on!


geoffreyh - 22/6/05 at 02:39 PM

NS,

Thank you for your reply.

I haven't understood the last sentence quite well. Are other Porsche transaxles an alternative?

If so which ones? Or are they all an alternative?


JAD - 22/6/05 at 04:52 PM

I think it was on one of the GT40 build sites, but a lot of people seemed to be using Audi units.


violentblue - 23/6/05 at 02:07 PM

I've come across a couple sites detailing the build of lambo replica's, the Audi transaxle has been used with some amount of reliability, paired to all manners of V8's and even a couple V12's


crbrlfrost - 4/7/05 at 07:28 PM

Isn't the transaxle used in the audi A4 2wd the same ZF box thats in the Porsche boxster? Might have slightly different ratios and such, but I'm pretty sure I read that, and the cable shifter from the porsche being able to bolt right on. Don't know torque capacities, but I'd imagine they are higher than the old porsche boxes. Actually, I think the 915 trans from porsche was a pretty stout piece of kit, but the earlier 901 was getting fragile at around 300ftlb. Hope some of this might help. Cheers!


Aloupol - 4/7/05 at 07:41 PM

Hey another belgian here..
Don't forget the Renault transaxles, a R21 or R25 box can handle more than 300 hp.
The GT40 replicas (GTD40 etc.) often use it. They are plenty in scrapyards, I don't know much about the versions, diff ratios and so but you should search this way.


Bart Vangampelaere - 6/7/05 at 02:00 PM

as far as I know the Renault transaxles are most often used in the basic versions, in other words those build on a tight budget and thus less powerfull. I'm not sure what version was in the Renault-Alpine, nor how much hp it can take, but I'd guess that'd be the best bet. Don't forget most transmissions will take the abuse of high hp quite good, it's the torque that blows them to pieces. This is a very important thing to remember, because V8's typically make a lot of torque due to their size.
If you will use a tuned V8 and plan to drive it seriously, you might really want to get a porsche box.

Btw, I'm also located in Belgium.

[Edited on 6/7/05 by Bart Vangampelaere]


ned - 6/7/05 at 03:02 PM

don't forget hewland of course not the cheapest option ( a mate reconned he could pickup an ftr for about 3k) but with a different diff they should handle 350-400bhp and thats tried and tested on the track. 6 speed straight cut sequential aswell


imull - 21/8/05 at 08:19 PM

I have decided on my next project and am starting the planning side of things and just stumbled across this thread. Couple of years off starting anything though

I decided agains building a Locost due to the weather where i live so plan to do something a mate and i toyed with doing when at uni.

I want to mid mount a V8 into the back of a mini pickup (or possibly van)


Just got to build my house now so that I have the garage space


Grintch - 30/8/05 at 08:42 PM

How about the transaxle out of a C5 Corvette (rear mounted like a Porsche 924 for better weight distribution)? 6 speeds and desinged to handle large V8 torque levels.


kb58 - 31/8/05 at 02:07 AM

I'd like to know the power handling capacity of the various Audi transaxles. Anyone know of a compiled source?


ProjectLMP - 1/9/05 at 03:11 AM

Regarding the strength of audi gearboxes, I have some real world experience. I used to have a 1999 S4 with modified turbos that put out 415hp and 495 ft/lbs of torque. I used this for a couple of years including quite a few track days with no problems at all.


kb58 - 1/9/05 at 05:11 AM

Thank you! The one you describe sounds extremely capable, perhaps even more then I could make use of. In other words is there a lighter duty (cheaper, more available) unit capable of perhaps 250-300hp and 250ft-lb of torque?

Oh, does the unit you're using come with, or have available, a limited-slip?


andygtt - 1/9/05 at 11:59 AM

I'm using a Porsche GT3 box in my car although its hardly a budget option (3 times price of a G50 2nd hand).... The Porsche 930 (older 4speed) is an excellent choice for the cost concious and can take even more abuse than the G50.
Don't worry about it having less gears as the torque of the chevy lends itself better to less gears anyhow (I built a 500bhp Ultima with a 930 box).

The audi is a very good option (if you get the right model of cause) as it's proven to 400bhp and can be purchased new for only a bit more than a 2nd hand G50.

The corvette box is extremelly long and unless you have nearly 2 foot more length than an Ultima its not an option.

Just remember the more exotic you go the more expensive the adapter plate will be (I have a BMW to G50 adapter going cheap!).

Andy


Grintch - 1/9/05 at 02:52 PM

How would you covert a gearbox out of an AWD Audi (or Subie) to 2WD?