Actually, the Porsche 928 transmission is very robust and does very well, in most high performance applications. Most of the current generation of "race" engines are based around welded cams (limited in what one can achieve) and intake systems that limit horsepower, but make lots of torque. These "torque monster" engines can be hard on the gearboxes, in certain applications.

The next generation of race engines (now) will have cams with more duration/lift and intake systems that make more horsepower in the higher rpm ranges.

This will reduce the "strain" on the transmissions from the torque loads. Combine this with a couple of changes within the transmissions themselves, and these transmissions will be more than adequate.

 

Greg-

Not sure what race engines you're referring to that will be easier on trannies. Please explain.

Seems the problem is that torque offers a lot of benefits coming out of turns (and it feels SOOO good). My current LS7 build is gunning a lower & wider torque band, dropping my shift points from 6600-7000 to about 5600-6000, knowing that I can occasionally stretch it to 7k if there's some purpose in doing so.

If you can stay on pavement, off curbs and control your application of power, the 5 speed would have a much better chance of staying alive. But, that's not what usually happens at the track. Drop a wheel and come back on the track under full throttle and bingo, you're likely on the trailer.

Thanks SVP928

I gave it to her when I got a 2000 E55. Sold that piece of crap almost immediately, but by then she wouldn't give it back. Now I drive a truck.

As to the other tranny options, believe me, we're looking at all of them, especially the C5 EMCO.

 

For the last decade performance has focused on torque due to the 6/2 issues at higher RPM. If that is now sorted out the new gains will be in HP at higher rpm and less torque. Instead of leaving the turn at 4200 rpm in third, maybe you would be at 6500 in second.

I don't think escaping damage from shock torque is likely with any kind of small mods, tranny, spider gears, or half shafts will break.

 

Larry sorry to hear the wife is a "hoarder". Lol....

I still think we could get a 928 diff grafted onto a Jerico/Tremec/whatever- and have some options. I'm talking to Greg about it now. The stock box seems to survive OK, like he says, but doesn't take much abuse.. but not many boxes do- even racing trans can be high-maint....we rebuilt the Hewlands in Can-Am and F5000 EVERY RACE...I hear the 996-7 Cup sequential is rated at 35 hrs..

 

Exactly. Anyone can break a transmission...no matter who built it or what pieces are inside...if they don't understand the hell that a transmission goes through.

I've had drivers that never hurt a transmission and drivers that can kill a gearbox in 60 minutes.

It's all about the "seat cover".

 

The next generation of race engines, for the 928, will have larger cams and induction systems that move the power range up a bit. We've tried to do this, but our hands have been tied, due to lack of available pieces.

We're never going to be able to turn the 928 engine into a high reving F-1engine. They are always going to have boatloads of torque. However, the current mid range torque is so high that we are having issues with transmission "over loading", with certain drivers. Loosing 50 or even a 100 foot lbs. of torque in the mid range and moving it up a bit in the rpm range will not make the cars slower out of the corners (you can't use all the current torque anyway...they just spin the tires). It will simply reduce the destructive mid range torque.

Certainly, the early transmissions, with the small bearings and smaller pieces, are never going to be high torque application race transmissions. By the time the cars got to the "GT' vintage transmissions, they certainly were much more robust. While Porsche did make some changes to the GTS transmissions, to make them handle more torque, certainly some of these modifications reduced the capacity, instead of helping it.

 

Brian,

I just saw this after sending you a PM on the subject

Is the pan itself different (from what i can see the casting looks identical) or is the screen thats shown the beneficial part of the conversion