PDK Over-Revs

GT3 Racer · 11-02-2009, 06:59 PM

Is it possible to over-rev a PDK equipped car?

Bob Rouleau · 11-02-2009, 07:34 PM

No it is NOT possible unless you have a very very steep hill long enough to get the car over 200 MPH in top gear

Edgy01 · 11-03-2009, 12:18 AM

I think you'd have a heck of an argument in your favor with Porsche if it did!! I would love to see them try to weasel out of that one if an engine over revved. The only way I can see it happening is if the car is entirely out of gear, and someone pushes the accelerator to the floor with no regard to the RPMs. Once it gear, it should never over rev, by design.

OldGuy · 11-03-2009, 01:56 AM

You may be able to bounce if off the rev limiter. But electronics will save you.

Carrera GT · 11-03-2009, 02:11 AM

While it's possible, in Sport Plus, to downshift to 1st at the redline, it seens not to be possible to get 1st gear anywhere near close to the redline under full brakes (I mean on the track, literally as much force as you can apply with your leg or both legs if need be.) I've played with this for dozens of laps and the car consistently refuses to go to 1st (and will even upshift to 2nd once PSM intervenes.)

PDK also has some "rules" about a downshift into 1st with certain degrees of steering input. I presume that most of the constraints on getting 1st pertain to stability and PSM rather than PDK being worried about the engine speed. The conflict I see is that PDK can only disengage both clutches, it couldn't intervene with the brakes to protect the engine (compromising the primary objective of protecting the occupants of the car ...)

I have by no means come to understand how it all works together "in extremis" but it has some very specific "out of bounds" conditions where it will do whatever it deems necessary to keep the car in a "plausible" envelope of all its sensors (the one it fears the most is yaw, but PDK and PSM have no qualms about four wheel drifts, understeer or oversteer, they just want to see those transitions occur within reasonable degrees of rotation.)

Anyway, suffice to say I have no doubt it's possible for PDK to allow the engine to overrev into at least some of the code ranges in traction-related conditions, but I doubt it's possible to "fool" PDK into a "money shift."

OldGuy · 11-03-2009, 02:34 AM

What he said^

fpb111 · 11-03-2009, 08:39 AM

After watching the technical presentation in this video and the subsequent Master tech explanation, one might have a better idea of how a Porsche PDK trans works. Be sure to pay attention to the the section where the Master Technician explains about using the proprietary tester and billable hours.

It almost looks like Porsche and Mercedes were sharing some ideas Mercedes brought back from Chrysler.

http://www.break.com/index/understan...cabulator.html

savyboy · 11-03-2009, 09:30 AM

[quote=Edgy01;7041358] The only way I can see it happening is if the car is entirely out of gear, and someone pushes the accelerator to the floor with no regard to the RPMs.QUOTE]

Nope, it hits the limiter, right at redline. You can't over rev in neutral/park.

mambodoc · 11-03-2009, 10:04 AM

Would love to see the video but cannot access it...

mambodoc · 11-03-2009, 10:25 AM

Belay that...break.com has some cool PDK tracking videos... Thanks man!

Carrera GT · 11-03-2009, 11:29 AM

Quote:

Originally Posted by fpb111

After watching the technical presentation in this video and the subsequent Master tech explanation, one might have a better idea of how a Porsche PDK trans works. Be sure to pay attention to the the section where the Master Technician explains about using the proprietary tester and billable hours.

It almost looks like Porsche and Mercedes were sharing some ideas Mercedes brought back from Chrysler.

http://www.break.com/index/understan...cabulator.html

http://www.break.com/index/understan...cabulator.html

(still makes me laugh uncontrollably)

larrytrk · 11-03-2009, 11:47 AM

I believe my lunar waneshaft is out of phase!!

OldGuy · 11-03-2009, 12:48 PM

Hey thats the same definition I give my kids when they ask how something works.
I keep going until:
A: they leave the room or
B: they ask their mom another question

No HTwo O · 11-03-2009, 01:33 PM

What if you spun the car, on the track for example, and spin the engine backwards??? Could it over-rev?

Bob Rouleau · 11-03-2009, 01:38 PM

Quote:

Originally Posted by No HTwo O

What if you spun the car, on the track for example, and spin the engine backwards??? Could it over-rev?

I'll hazard a guess that unless you were going faster backwards than forwards before you spun the answer is "no".

11-02-2009, 06:59 PM	#1
GT3 Racer Addict Rennlist Member Join Date: Sep 2004 Posts: 297	PDK Over-Revs Is it possible to over-rev a PDK equipped car?

11-02-2009, 07:34 PM	#2
Bob Rouleau Administrator Still plays with cars. Lifetime Rennlist Member Join Date: Jul 2001 Location: Montreal Posts: 7,831	No it is NOT possible unless you have a very very steep hill long enough to get the car over 200 MPH in top gear __________________ ..Bob Frozen North Rep & ceramic rotor roaster Hey, wait for me! racing.

11-03-2009, 12:18 AM	#3
Edgy01 Poseur Rennlist Member Join Date: Nov 2005 Location: Santa Barbara, CA Posts: 9,280	I think you'd have a heck of an argument in your favor with Porsche if it did!! I would love to see them try to weasel out of that one if an engine over revved. The only way I can see it happening is if the car is entirely out of gear, and someone pushes the accelerator to the floor with no regard to the RPMs. Once it gear, it should never over rev, by design. __________________ Dan 06 997S PCCB Hard-Top Cabrio Turq. Blue, Nat. Brn Leather http://www.rennteam.com/photopost/sh...00&ppuser=8756

11-03-2009, 01:56 AM	#4
OldGuy Addict Lifetime Rennlist Member Join Date: Jun 2003 Location: Ridgecrest, and Mammoth California Posts: 7,847	You may be able to bounce if off the rev limiter. But electronics will save you. __________________ OG 997 09 C2S PDK Carrera White Rennlist member# 030815-4002 Official NRA Liason to Sierra Club HWFMR paulgt3@gmail.com 2008 BMW 335i (wifey's) 2006 BMW X5 4.8iS 04 GT3 RSR Le Mans entrant Gone 97 993 TT midnite blue/cashmere(missed) 04 RED 996 GT3 2007 GT sliver GT3 2009 AMG C63

11-03-2009, 02:34 AM	#6
OldGuy Addict Lifetime Rennlist Member Join Date: Jun 2003 Location: Ridgecrest, and Mammoth California Posts: 7,847	What he said^ __________________ OG 997 09 C2S PDK Carrera White Rennlist member# 030815-4002 Official NRA Liason to Sierra Club HWFMR paulgt3@gmail.com 2008 BMW 335i (wifey's) 2006 BMW X5 4.8iS 04 GT3 RSR Le Mans entrant Gone 97 993 TT midnite blue/cashmere(missed) 04 RED 996 GT3 2007 GT sliver GT3 2009 AMG C63

11-03-2009, 02:11 AM	#5
Carrera GT Addict Rennlist Member Join Date: Feb 2003 Posts: 3,929	While it's possible, in Sport Plus, to downshift to 1st at the redline, it seens not to be possible to get 1st gear anywhere near close to the redline under full brakes (I mean on the track, literally as much force as you can apply with your leg or both legs if need be.) I've played with this for dozens of laps and the car consistently refuses to go to 1st (and will even upshift to 2nd once PSM intervenes.) PDK also has some "rules" about a downshift into 1st with certain degrees of steering input. I presume that most of the constraints on getting 1st pertain to stability and PSM rather than PDK being worried about the engine speed. The conflict I see is that PDK can only disengage both clutches, it couldn't intervene with the brakes to protect the engine (compromising the primary objective of protecting the occupants of the car ...) I have by no means come to understand how it all works together "in extremis" but it has some very specific "out of bounds" conditions where it will do whatever it deems necessary to keep the car in a "plausible" envelope of all its sensors (the one it fears the most is yaw, but PDK and PSM have no qualms about four wheel drifts, understeer or oversteer, they just want to see those transitions occur within reasonable degrees of rotation.) Anyway, suffice to say I have no doubt it's possible for PDK to allow the engine to overrev into at least some of the code ranges in traction-related conditions, but I doubt it's possible to "fool" PDK into a "money shift."

11-03-2009, 08:39 AM	#7
fpb111 Addict Rennlist Member Join Date: May 2008 Location: Northern NJ Posts: 169	After watching the technical presentation in this video and the subsequent Master tech explanation, one might have a better idea of how a Porsche PDK trans works. Be sure to pay attention to the the section where the Master Technician explains about using the proprietary tester and billable hours. It almost looks like Porsche and Mercedes were sharing some ideas Mercedes brought back from Chrysler. http://www.break.com/index/understan...cabulator.html __________________ 1972 RS 3.2 twin plug short stroke crank fire, roll bar, camber truss, factory short shift, turbo brakes sadly sold 2003 996 cab 6 speed happily bought 22 year PCA instructor Past NNJR social chair, past rally chair, past fresh sell by date Frank

11-03-2009, 09:30 AM	#8
savyboy Addict Rennlist Member Join Date: Nov 2008 Location: Reno NV Posts: 207	[quote=Edgy01;7041358] The only way I can see it happening is if the car is entirely out of gear, and someone pushes the accelerator to the floor with no regard to the RPMs.QUOTE] Nope, it hits the limiter, right at redline. You can't over rev in neutral/park. __________________ 2010 GT3RS Blue/Gold, PCCB, Front axle lift, LiON Battery, NAV, AUX, XM. Feb 8th Build. 2009 C4S Meteor Grey/Carrera Red, PCCB, AMT Tech1-109's (Matte Black), FVD Brombacher Full Exhaust, PDK, Sport Chr Pkg Plus, Sport PASM, etc 2009 Cayenne GTS Meteor Grey/Sand, Porsche Dynamic Chassis Control, 18" Nitto Terra Grapplers/Victor Zehn (Matte Black)

11-03-2009, 10:04 AM	#9
mambodoc User Join Date: Aug 2005 Location: Ormond Beach, Florida Posts: 298	Would love to see the video but cannot access it...

11-03-2009, 10:25 AM	#10
mambodoc User Join Date: Aug 2005 Location: Ormond Beach, Florida Posts: 298	Belay that...break.com has some cool PDK tracking videos... Thanks man!

11-03-2009, 11:47 AM	#12
larrytrk Addict Rennlist Member Join Date: Apr 2006 Location: Central NJ & MA Posts: 777	I believe my lunar waneshaft is out of phase!! __________________ 09 997S Black/Black-PDK-wow! 06 997S Seal Grey/Stone Grey-gone 87 Westy Camper

11-03-2009, 12:48 PM	#13
OldGuy Addict Lifetime Rennlist Member Join Date: Jun 2003 Location: Ridgecrest, and Mammoth California Posts: 7,847	Hey thats the same definition I give my kids when they ask how something works. I keep going until: A: they leave the room or B: they ask their mom another question __________________ OG 997 09 C2S PDK Carrera White Rennlist member# 030815-4002 Official NRA Liason to Sierra Club HWFMR paulgt3@gmail.com 2008 BMW 335i (wifey's) 2006 BMW X5 4.8iS 04 GT3 RSR Le Mans entrant Gone 97 993 TT midnite blue/cashmere(missed) 04 RED 996 GT3 2007 GT sliver GT3 2009 AMG C63

11-03-2009, 01:33 PM	#14
No HTwo O Addict Rennlist Member Join Date: May 2008 Posts: 868	What if you spun the car, on the track for example, and spin the engine backwards??? Could it over-rev?