Don Terrill’s Speed-Talk

I would like to know which transaxle transmission will fit the SBC and can handle the torque of a 500 - 600 hp engine.

Thanks

Hewland was used in the Can Am series.

How about Mendola ?

http://ranchotransaxles.com/mendeola-transaxles.html

How much are you looking to spend? How heavy is the car and what is It's purpose? Also, which SBC, GenI/II or GenIII/IV?

Just about any transmission can be made to fit, and depending on what you need you may find it makes more sense to adapt a transaxle rather than find one that already fits.

I've seen the Hewland but they are superexpensive.

As for car weight. I intend to make a one seater, à la Can Am. I would have to guesstimate, but would say 500-700 kgs

It's common to use an adapter plate from Kennedy Engineering with a Porsche G50 or Audi transaxle.
You can get a ready to use kit from them with a flywheel and clutch.
The Medolas Ian mentioned look interesting.
This has been the age old dilema, a transaxle for a V8.
There's never been anything in between the Porsches/Audis and serious race boxes like Hewland.

BTW, being in Europe you have the Renault UN1 which seems to be popular in GT40 kit builds.
Visit the transaxle forum on GT40S.com

500-700 kg is a big range, but I would think a G50 would handle it. If you can find a good used gearbox from a Ford GT, that would work also, though they are far more rare.

Does a G50 handle the torque/hp output of a SBC ?

Belgian1979 wrote:Does a G50 handle the torque/hp output of a SBC ?

Maybe!

That sounds like a lame answer but there are so many variables that it's actually the best answer.

I do know about the 928 version of that Porsche G50 box. I just broke gears in one with a 2900 lb race car on slicks. The teeth broke off 4th gear.
If it were a street car it probably would have been just fine forever.
I've also put big power into a weaker 901 box and it didn't break even though they are considered a weak box. That was a small turbo engine on street tires.

Did you visit GT40s yet?

The guys over at http://www.factoryfive.com use the G50 for their GTM kit cars. They live behind Chevy LS motors with no issues. I think they've used SBC's in prior builds with the G50 also. Maybe contact them for advise. Not sure if they will sell the adapter kit but it's worth a call.

G50 out of the turbo porche 911's will live but can get pricey. The lesser variants would hold up driven semi-sane in a street vehicle. Few launches at the strip though and you probably wish you hadn't.

the G50 is not a good choice, old style Porsche box and clutch choices are an issue. Getting very pricey these days, even clutches are horrible expensive and one issue is the starter mounts from behind to it and tends to brakes mounting ears off on high compression LS1. A cable shift conversion is highly recommended or it will by so slush to shift that it gets annoying at the track. Done a few GTM's that way.

here most prefer an Audi tranny, much cheaper, holds much better up and even used in the Gumpert Apollo behind a 700hp twin turbo V8. Conversion plates exist for both.

the aforementioned Renault tranny used ion GT40 kit cars is a relict at best and uses a tiny small clutch, most of them on Ford need to use a fully modified Ford essex V6 flywheel which needs a ton of machining and balancing (that is the old 3.0l Capri engine from the UK), I have just been through with one of those conversion for an aging GT40 kit car. Not recommended

coolchevy wrote:the G50 is not a good choice, old style Porsche box and clutch choices are an issue. Getting very pricey these days, even clutches are horrible expensive and one issue is the starter mounts from behind to it and tends to brakes mounting ears off on high compression LS1. A cable shift conversion is highly recommended or it will by so slush to shift that it gets annoying at the track. Done a few GTM's that way.

here most prefer an Audi tranny, much cheaper, holds much better up and even used in the Gumpert Apollo behind a 700hp twin turbo V8. Conversion plates exist for both.

the aforementioned Renault tranny used ion GT40 kit cars is a relict at best and uses a tiny small clutch, most of them on Ford need to use a fully modified Ford essex V6 flywheel which needs a ton of machining and balancing (that is the old 3.0l Capri engine from the UK), I have just been through with one of those conversion for an aging GT40 kit car. Not recommended

Which Audi trans and where do you get the adapter ?

Yes, please do tell which Audi box is preferred. I have a 6spd from an S4 laying around, if It's worth anything I will try the GT40 forums...

sorry for late reply, mostly used are the trannys out of the 2,5l turbo diesels from A4 and A6. In light weight cars track proven to about 650 hp behind LS engines and up to 750-800 Nm = 550 ft lbs.

The neat part is that you just use a LS1 flexplate for the starter and it is easy top modify a stock flywheel to mount onto it. Thus, no need for expensive aftermarket clutch/hydraulic slave cylinders, stock Audi will work fine as these diesels are known for big torque.

If you use a Fichtel&Sachs race clutch and a Quaife LSD almost indestructible and cheap, remanufactured they cost here less then a 1000 bucks.

I can post picture, for guys from Europe we have water jet cut Adapterplates as I am supplying LS1 engines to a newly started Lola T70 street legal kit car fabrication.

for those who are not so familiar with Lola, a T70 (symbolic picture from one at Silverstone circuit) would be this thing here..... will be custom steel tube chassis, fiber glass body, weight about 2050 lbs, slightly modded LS1 with 410 hp and Audi transmission build in Austria

Practically all mid-engined sportscars from the mid-'60s to about the mid-'90s used a ZF, specifically the 5DS-25/2. Used by Fords GT-40s at LeMans 24 hr, all Panteras, BMW M-1s, the Maserati mid-engines, many kit-cars. New parts & pro rebuilds still available from RBT Transmissions in So-Cal <www.rbttrans.com>. Found by experience to hold about 650-700 bhp continuous or maybe more if you shift easy. Many gear ratios available- none cheap. Comes with a clutch-type LSD on both stub axles, some models used CV joints, most used Hooke u-joints. Weighs 155 lbs, can be lightened to 135 lbs or maybe less, without affecting strength. Originally a 5-speed but RBT has a 6-speed intended for Ford's GT wit h blown 5.4 mod-motor. Ford eventually went to the Ricardo- a 200-lb monster 6-speed. To run a SBC with a ZF, all you need is a bellhousing. Hewlands are even more expensive and get extra strength from not using synchros so the gears can be wider. Practice your clutchless shifting before running a Hewland.