Drag Strip: PSM On vs Off
06-02-2019, 09:31 AM
#1
Drag Strip: PSM On vs Off
I took my 2011 Turbo S convertible to the drag strip for the first time this past Friday to see what it could do. I had also done some research before I went and it looked like most folks recommended running with traction control off so I started with the Porsche Stability Management (PSM) turned off. In my first run I could feel the car wiggle a little but it did go straight. In the second run the car instantly veered to the right so I let off the accelerator slightly and steered the car straight. That scared the heck out of me so for my next runs I kept the PSM enabled and the car behaved perfectly with no drama. Not sure if others have had this experience or not, but I know I will now be keeping the PSM on all the time.
Here were my runs in order:
PSM Off: 11.614, 11.740
PSM On: 11.548, 11.525, 11.593
It really is amazing how consistent the runs all were using launch control.
Here were my runs in order:
PSM Off: 11.614, 11.740
PSM On: 11.548, 11.525, 11.593
It really is amazing how consistent the runs all were using launch control.
06-02-2019, 10:56 AM
#2
Burning Brakes
They don't call PSM
Please
Save
Me
for nothing.
Please
Save
Me
for nothing.
06-02-2019, 01:47 PM
#3
Rennlist Member
06-02-2019, 07:52 PM
#5
Instructor
I took my 2011 Turbo S convertible to the drag strip for the first time this past Friday to see what it could do. I had also done some research before I went and it looked like most folks recommended running with traction control off so I started with the Porsche Stability Management (PSM) turned off. In my first run I could feel the car wiggle a little but it did go straight. In the second run the car instantly veered to the right so I let off the accelerator slightly and steered the car straight. That scared the heck out of me so for my next runs I kept the PSM enabled and the car behaved perfectly with no drama. Not sure if others have had this experience or not, but I know I will now be keeping the PSM on all the time.
Here were my runs in order:
PSM Off: 11.614, 11.740
PSM On: 11.548, 11.525, 11.593
It really is amazing how consistent the runs all were using launch control.
Here were my runs in order:
PSM Off: 11.614, 11.740
PSM On: 11.548, 11.525, 11.593
It really is amazing how consistent the runs all were using launch control.
Bill
Last edited by tinkerbill; 06-02-2019 at 07:53 PM. Reason: .
06-03-2019, 05:12 AM
#7
Tinkerbill - The car launch really did not feel "violent" on the drag strip. The surface is very sticky and I did not detect any wheel slip. Plus you have your windows up and your helmet on so all sounds are somewhat muted as well. To me, the car has actually felt/sounded faster when I have gunned it on some back roads (with the top down) and where I have felt all 4 wheels trying to get traction and pull the car forward. The drag strip was almost tame in comparison. That being said, I wouldn't use launch control a million times but you definitely owe it to yourself to try it a few times just to experience it and know what the car can do.
Atm4jim - 60 foot was 1.8 sec and trap was 122 mph. For grins I calculated that it took 3.5 sec to hit 60 mph. I was hoping that these and my overall times would be a hair quicker but I am guessing this 8 year old car has lost just a bit compared to when it was new and all the car magazines reported low 11's for their times. Of course those were probably with cooler temperatures and newer stickier tires.
Atm4jim - 60 foot was 1.8 sec and trap was 122 mph. For grins I calculated that it took 3.5 sec to hit 60 mph. I was hoping that these and my overall times would be a hair quicker but I am guessing this 8 year old car has lost just a bit compared to when it was new and all the car magazines reported low 11's for their times. Of course those were probably with cooler temperatures and newer stickier tires.
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06-03-2019, 11:11 AM
#8
Burning Brakes
Right now I can't handle even a 90% acceleration in sport mode. Although embarrassing, I am going to post openly in hopes it might help others. The best I can manage is a 90% from rolling in normal mode.
I want my car to last over the long run. It's one of the reasons I don't do 100% standing starts and especially considering all of the research coming out about fuel dilution, long idles and LSPI - which AFAIK the process of waiting and staging at a typical drag strip set up the 'perfect storm' for.
06-07-2019, 07:12 PM
#9
I literally have hundreds of passes in my 997.1 turbo and can promise your best times will likely come with traction control on. I'm running 10.2 - 10.4, 136 mph trap times, and 1.4 60 foot. Unless you're a phenomenal driver, the car will manage your tire slip much better than you can. I run Toyo R888s, and even with excellent track prep, the tires will still slip in gears 1, 2, 3. I would focus on getting the best 60 foot time you can. Each tenth of a sec improvement there usually leads to about 1.5 tenths better on your 1/4 time. Also, you don't need to go ***** out when you launch, try and drive right on the edge of slip so traction control doesnt have to intervene. Make sure you drive around the water box. I know it seems obvious, but make sure you're starting in 1st gear--sometimes my car likes to be in 2nd at the line. Don't spend too much time trying to boost at the line as the overboost function only lasts a short time. Finally, try and time your shifting so you stay in the range of maximum torque. That point is usually before redline. Good luck and let us know how it goes.
06-07-2019, 08:00 PM
#10
Rennlist Member
I've driven my 997.1 60k kms, making it now over 150k kms on the clock - I've mashed the pedal to WOT more times than I could possibly count, and the car is running fine. Don't be scared of the beast, it's easy to tame 
06-09-2019, 01:27 PM
#11
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For the Drag Strip, I run it OFF. As long as traction is good (track prep).
I cut my best 60 ft. with it OFF....
When my car was stock, I cut a 1.55 60ft. on Michelin PS2's with just slightly lower pressures. (not the stickiest tires and certainly not the best for drag racing)..
During that 1.55 60ft. my car ran a 10.96 @ 124.1 mph in 90 degree humid sunny weather.
On drag strip with it OFF, even if traction is not perfect, it shouldn't be that hard to keep it straight with minor corrections. Maybe you just need more practice and get used to it getting stepping out a bit.
I cut my best 60 ft. with it OFF....
When my car was stock, I cut a 1.55 60ft. on Michelin PS2's with just slightly lower pressures. (not the stickiest tires and certainly not the best for drag racing)..
During that 1.55 60ft. my car ran a 10.96 @ 124.1 mph in 90 degree humid sunny weather.
On drag strip with it OFF, even if traction is not perfect, it shouldn't be that hard to keep it straight with minor corrections. Maybe you just need more practice and get used to it getting stepping out a bit.
Last edited by Big Swole; 06-09-2019 at 01:46 PM.
06-09-2019, 01:33 PM
#12
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His is a TTS which had a Locking Diff. as standard equipment.
I literally have hundreds of passes in my 997.1 turbo and can promise your best times will likely come with traction control on. I'm running 10.2 - 10.4, 136 mph trap times, and 1.4 60 foot. Unless you're a phenomenal driver, the car will manage your tire slip much better than you can. I run Toyo R888s, and even with excellent track prep, the tires will still slip in gears 1, 2, 3. I would focus on getting the best 60 foot time you can. Each tenth of a sec improvement there usually leads to about 1.5 tenths better on your 1/4 time. Also, you don't need to go ***** out when you launch, try and drive right on the edge of slip so traction control doesnt have to intervene. Make sure you drive around the water box. I know it seems obvious, but make sure you're starting in 1st gear--sometimes my car likes to be in 2nd at the line. Don't spend too much time trying to boost at the line as the overboost function only lasts a short time. Finally, try and time your shifting so you stay in the range of maximum torque. That point is usually before redline. Good luck and let us know how it goes.
His is a TTS / PDK. Launch Control is a set RPM and there's no "picking gears" or "managing" revs.
He simply needs either / Or Better tires...Correct Lower Tire Pressures.. Or a Better prepped Track.
06-09-2019, 01:37 PM
#13
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Here are my two recorded passes.
First in Very Hot Humid conditions during the day. PSM ON ---- 11.24 @123.06 (1.649 60Ft. - Stock car with exception of my Europipe)
The second in slightly less heat but some humidity in the evening. PSM OFF ---- 10.96 @ 124.1 ( The 1.55 60ft. --- Stock car with exception of Europipe)
First in Very Hot Humid conditions during the day. PSM ON ---- 11.24 @123.06 (1.649 60Ft. - Stock car with exception of my Europipe)
The second in slightly less heat but some humidity in the evening. PSM OFF ---- 10.96 @ 124.1 ( The 1.55 60ft. --- Stock car with exception of Europipe)
06-09-2019, 01:43 PM
#14
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Now, on the street in Mexico at OEM tire pressures, You'll get best 60 fts. (0-60) with PSM ON. (OTS Cobb tune and now runs best of 132.6 Trap in good weather / lower DA)
Here's an example of me testing on a street and you can hear it struggling for traction. 1.83 60Ft. here. Still managed a 0-60 in 3.18 sec. with bad spinning.
Here's an example of me testing on a street and you can hear it struggling for traction. 1.83 60Ft. here. Still managed a 0-60 in 3.18 sec. with bad spinning.
