ZF vs.Porsche gearbox limits...

Hello GT40 forum

I can see you have pretty hige knowledge about transaxles in this forum.

I have a Lotus Esprit turbo 2.2 4pot with 450bhp/ 400ft/lbs with a UN-1 box that is on its limits now I gess (I only use the 5th for cruising now and not use to mutch time in the hige torque RPM range...)And I gona put a Lexus 1uzfe V8+turbo in it.My modifyed Esprit deservs a V8.

Have got some info from a Replica F40 with a Lexus V8 twinn turbo engine running 750bhp and 650ft/lbs with a ZF gearbox.He did race it for 3 years before 4th gear let go....

What du you regard as the strongest box between ZF and the porsche 5 speed box? How mutch torque do you regard max???

Depends on your driving technique. Any gearbox can be broken no matter what name is stamped on its side. But since Porsche boxes are more plentiful, you may be better going with one of them.

"Porsche boxes are more plentiful"

Not sure that I agree with that, for a turbo Lexus since he wants a five speed he will need the G50/5x turbo box. How many of those have you seen for sale recently? And the prices they are fetching are not that far short of ZF prices. It's almost worth springing that little extra for the ZF.

I feel that the strength of both trans is similar, and that the 4 speed 930 is stronger than both. Don't overlook the 4 speed, the 5 speed Porsche really has a first that is too low to be useful for racing IMHO. And even with custom ratio's is still not quite there. The 930 price is much better too, and they are more readily available. Custom ratios for the 930 are much better too.

I am told Porshe parts are cheaper than ZF also but I haven't checked that out.

Regards

I dont reckon it's easy to answer this question which can handle more than another. I reckon the way the driver treats the box is a big factor.Just like in my business some people blow speakers where others don't. If your a ram it through the gears with no mechanical feel you will destroy gearboxes.These guys do exist even on the track and they generally have fat cheque books and drive Porsches but never get their hands dirty.Sorry for offending anyone who may hate me for that.So I will use the speaker analogy again and say that if you play your music loud you need to have speakers with a power rating probably twice that of the driving amplifiers power.Likewise if your not gearbox sympathetic use a box with much higher torque capability. I personally drive my car hard on the track but always try to shift smoothly. I have not been able to beat the ZF synchros yet so shifts are smooth.Only problem is everytime I modify the shift, I have to change my shift technique. I have miss the odd gear but in 2.5 years of racing with the ZF no problems at all.I love them. Russ I think that G50 ist gear is 3.6 isn't it? That is way too low. Off the start you would be forced to change so early Ross roars by in the GT40.
Ross

Thanks a lot for the answers i got.

""Not sure that I agree with that, for a turbo Lexus since he wants a five speed he will need the G50/5x turbo box. How many of those have you seen for sale recently? ""

Well, I think they're everywhere. I have had no trouble locating a G50/52 or anything else. If they dont come up on Ebay or TradeMe doesnt mean they are thin on the ground. If you have the money, you can buy anything.
People say Renault UN1-13, 21 turbo boxes are rare and here I have 4 sitting in my garage in New Zealand, amoungst others. I have sold 6 of them off over the last 3 years.
I guess its just a matter of who you know and the power of the internet.