GrantG

My mechanic who works on my Evo has a big business improving the GTR's gearbox. He has mods that make it reliable with up to 1,200 wheel ft-lbs:

http://www.jackstransmissions.com/pa...-gr6-options-1

His next business ambition is to become the national expert on repairing and improving the Porsche PDK gearboxes...

CAlexio

Do PDK transmissions fail?

How does he improve on a gearbox which a company with relatively unlimited funds has carefully engineered? Really interested, not being cynical

GrantG

PDK transmissions are built to a very specific torque spec maximum, with respect to the engine that is bolted to them. For several years now, you have not been able to buy a 911 Turbo without ordering PDK (began in the 997.2). The turbocharged 911 motor has always lent itself to huge power and torque gains in tuning by adding higher capacity turbochargers and other bolt-on parts. With PDK, there is now a ceiling on responsible tuning (in order not to exceed the torque capacity capabilities of the gearbox in stock form). His mods would significantly raise this ceiling for the purposes of drag and road racing.

Read about his modifications on the GT-R dual-clutch gearbox (which is prone to failure even without engine mods) to get an idea of what is involved (one common mod is exchanging the clutch mechanisms for ones that will not slip or become damaged with very high output engines). Unlike manual gearboxes, the clutches are internal and not easily accessible for upgrading (a common mod for Porsches of the past that saw extreme use).

Also, once the PDK-S gearbox from the 991 GT3 is exposed to long-term road course tracking, weaknesses may appear that we have not seen yet with more mundane road use and shorter term tracking of the cars. I'm not saying Porsche cannot repair or upgrade these weak areas, but it is often incumbent on the aftermarket to offer such improvements before you begin to see factory improvements (which may not be retrofittable to cars already produced). Think about the LSD from previous generations of GT3 which has been shown to be inadequate for hard track use. I don't think this was ever addressed by Porsche over the 15 year run of GT3's - many track cars have had their LSD's replaced with Guard, Porsche Motorsport, or other units as an example.

95spiderman

Gtr transmission does not need to be 'flushed down toilet'. It was state of the art only 5 years ago. Problem is it hasnt been updated since then. Add 7 gear, improve shift logic, improve cooling, and will be set for next 5 yrs. Gtr trans failures are mostly seen with modded motors. My stock gtr has plenty of track days with no issues trans

991 3Turbo

Everyone here has their valid opinions, but as usual these threads usually descend into rants about perceived appearance and cheating and engine sound and reliability etc, etc, etc.

A few people here need to recheck their facts. The GTR price has gone up, but so has Porsche with the largest margins in the business. As far as resale, GTR has among the highest resale values of any car. Nissan prescribes to same paradigm as Porsche 911 in that it continues to tweak and make refinements to a well known car and not constantly change appearances and chase styles.

The only things I hated about the GTR were the ride which was extremely unforgiving even in comfort mode, and the unusually noisy cabin(not so much different than my Corvette). Nissan is solving these issues. I found the power and grip simply intoxicating, especially after having driven many very powerful cars in my past.

Cars are like art. You may like the look and may not. Doesn't mean anyone is wrong!. I personally like the GTR look, especially in person because it is so big and makes such a presence when seeing it. I also think the GT3 is personally the best looking modern 911 ever. The turbo is flat out IMHO not nearly as good looking.

Thanks for listening.

E

amerlemans

Excellent post. I own a 2010 GTR and agree with all of your points save for the Corvette comparison. My GTR is much noisier than my former '11 Grand Sport and '07 Z06. The C7 is even better yet and feels considerably smaller than the C6's.

Love the looks of the 991 GT3 and think it is the best looking 911 since the 993 Turbo. Not a fan of the 991 Turbo look. Also a big fan of the looks of the GTR.

neanicu

Check this guy out :

consolidated

^^ funny for what passes as automotive journalism now. Do you think Nissan put that helmet on him for grins, if so well done Nismo.

frayed

+1 !!

roberga

was waiting for his belly to get caught in the wheel.

Twosherpaz

++++++5

Tacet-Conundrum

Can someone tell me if they still have the Tranny issue with the new Nismo GTR as the original? You break it you buy another for $30K?

What was Nissan's resolution to that problem, Lower RPM launches and forget about VDC...

991 3Turbo

The Nismo isn't even out yet. Please sound a little more educated about the subject before you post nonsense.

kencollinsjr

Whatever weight Nissan / NISMO shaved in the development process were added back several-fold by the weight of that driver. Just sayin'. Fat man in a tiny carbon bucket...

Tacet-Conundrum

They should come out with a "SixSpeedOnline-Special" if that's the case.

That car for that time had to have been checking out at least 650, or more, BHP on a solo track. With some pretty damn hot shoes because we all know how much of a slug in reality the car is but Nissan has done a terrific job in countering with all its gizmos and gadgets and tricks of the trade. I'm not taking anything away from that car or time but in the hands of The Common Man just forget about. Just religate it to quarter miles and red light racin'.

I too, here in the States, grew up, with stories of sub 5 second AWD Skylines. Can't wait for the 25 year limit to pass to bring one in from England. What is that like four or dive more years I think?