Valvefloat991

That's correct. Unfortunately, the 991.2 has so much traction that it would benefit from a 6000 or so rpm clutch drop. That would provide sufficient wheelspin that the engine is developing full boost when the tires hook up. With the 4000--or I think it's 4200--rpm drop that the engine management system allows, the engine is yet developing full push when the tires stop spinning.

The only alternative method of getting the engine up to boost during a maximum launch is to slip the clutch, which is very hard on the clutch and also very difficult to execute with the perfect degree of slip.

Presumably Porsche has implemented this 4000-rpm limitation because the driveline won't withstand higher rpm clutch drops, at least not for long.

Interestingly, older Porsche had no such limitations, including the 993 Turbos, which would gloriously spin all four wheels when blasting off with a high-rpm clutch drop.

freeman

A clutch drop on a MT is like a death-wish for your clutch. I have done 8 Launch controls in a GT3 with PDK at PDE-Atlanta. I should apologize to the poor person who inherits that car. I would NEVER do that in my MT GTS. Who needs it?

AFX1

I also tried a .2 MT at Atlanta and the instructor had no worries about burning out the clutch on a fast takeoff from a standing start. Consider that these cars get hammered every day, 5 days a week for 6 months before ending up on a Dealers lot as a CPO.
Does the MT being a duel clutch (same as the PDK) make a difference?

JW911

Slipping the clutch is what kills it. If you get instant hookup when dropping the clutch and spin the wheels then it is your tires that take the beating, not the clutch.

Valvefloat991

The MT has two plates in a single clutch, which is very different than the PDK, which has two discrete clutches, each of which is a multiplate wet clutch.

It's the "wet" part that makes all the difference because the clutch fluid is circulated and actively cooled. That allows it to be slipped during the launch control procedure without overheating the clutch plates.

When you slip the dry clutch plates in a manual transmission, there is no means for removing the heat generated and that's what can cause the damage. That's why dropping the clutch and slipping your tires, while a violent procedure, is easier on the clutch, so long as nothing else lets go in the driveline.

coopmike

I wonder how to tell which CPOs are the PEC ones. I read in random thread about how to tell (possibly) from the carfax but haven't been able to find the post again.

AFX1

Best guess is that the PEC cars are not registered - no previous owner; leaving Dealer demonstrator with several thousand miles on the clock?