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In my search for a way to switch off the PSM fully in my car, among other things, I noticed in a members inside picture of his R that where there is a PSM button on my S there is a traditional traction control button on the R.
So my question is, do R's not come with PSM? And if so, would it be possible to replace the module or mechanism from a R to an S? both being 987.2 of course.
This pic I grabbed from the member with the Mickey D's Cayman R. The typical PSM button is actually a logo of a traction control button.
Furthermore, I noticed in the actual cluster that there is are two lights that are there to illuminate. The one on the right that illuminates when you switch off the PSM and one on the left that looks similar but never turns off.
Funny enough I was just browsing for info on PSM Off, and my own car is being referenced.
From what I've found here and on a couple other forums it appears the S and R have the same or similar PSM symptoms, which leads me to believe they are programmed the same. From what I understand any difference would be due to whether the car has an LSD or not. Here is my experience:
This weekend I had the car out at Thunderhill West, and with PSM Off and Sport Mode engaged, the car would not oversteer out of the slower hairpins no matter what I did. I believe this is due to my LSD being completely worn out and ready for an upgrade, which caused the inside wheel to spin and PSM to override my inputs (as it's never completely off). In February I was at an autox with intermittent rain, and with PSM Off and Sport Mode engaged the car would get all sorts of sideways. My assumption is that the lower grip levels allowed both wheels to spin up, and thus PSM remained dormant.
Not sure this helps, and over the years there seem to be a few different threads about defeating PSM completely if you're interested in that. I will probably do some more testing in an empty parking lot over the next couple of weeks to see if I can replicate specific conditions and behaviors. Also time to put a Guards diff on the to-do list.
Funny enough I was just browsing for info on PSM Off, and my own car is being referenced.
From what I've found here and on a couple other forums it appears the S and R have the same or similar PSM symptoms, which leads me to believe they are programmed the same. From what I understand any difference would be due to whether the car has an LSD or not. Here is my experience:
This weekend I had the car out at Thunderhill West, and with PSM Off and Sport Mode engaged, the car would not oversteer out of the slower hairpins no matter what I did. I believe this is due to my LSD being completely worn out and ready for an upgrade, which caused the inside wheel to spin and PSM to override my inputs (as it's never completely off). In February I was at an autox with intermittent rain, and with PSM Off and Sport Mode engaged the car would get all sorts of sideways. My assumption is that the lower grip levels allowed both wheels to spin up, and thus PSM remained dormant.
Not sure this helps, and over the years there seem to be a few different threads about defeating PSM completely if you're interested in that. I will probably do some more testing in an empty parking lot over the next couple of weeks to see if I can replicate specific conditions and behaviors. Also time to put a Guards diff on the to-do list.
which trackday provider did you go with? I usually do speedsf because it's pretty chill and I get a decent amount of runs.
Your feedback on the way PSM is working for you makes sense, so it's not the yaw sensor making it cut in but the difference from both rear wheel speed sensors spinning at different rates.
So far, I've been planning on installing a yaw cutoff switch but I'm still trying to figure out where best to wire it and place it for a nice clean install.
I decided on a wavetrac that should be getting installed in the next week or two, so we'll see how that goes.
which trackday provider did you go with? I usually do speedsf because it's pretty chill and I get a decent amount of runs.
Your feedback on the way PSM is working for you makes sense, so it's not the yaw sensor making it cut in but the difference from both rear wheel speed sensors spinning at different rates.
So far, I've been planning on installing a yaw cutoff switch but I'm still trying to figure out where best to wire it and place it for a nice clean install.
I decided on a wavetrac that should be getting installed in the next week or two, so we'll see how that goes.
I was out there with SpeedSF, it was a good time! Interested in your feedback once the Wavetrac is installed.
From my Owners Manual PSM is less sensitive in Sport/Sport+, but not off. Again from the manual. with PSM off it will stabilize when ONE of the front wheels enters ABS control in NORMAL. In Sport it takes TWO wheels in ABS control. "One-spinning of the wheels is prevented even with PSM switched off." My butt tells me I get more wiggle in Sport/Sport+, but definitely feel it kicking in driving in the rain. The few times I've Xcrossed I can easily lose the rear end with PSM off. An LSD seems to add another whole dimension to what PSM does.
I own a 987.1 S that has been modified with Tarett Cup LCA's, Swaybars, Ohlins, and a Wavetrac LSD. Just saying that this addition make racing in the rain manageable even with A7 slicks as long as there is not standing water on the surface. Coming out of a 180 degree corner to a straightaway, is totally different now. So, I use PSM to keep the ABS happy, and limit my slip angle to 8 degrees. But the most important quality here is the Wavetrac prevents the inside wheel from slipping to a point of triggering the PSM. It mechanically transfers power to the outside wheel as much as possible, but does not cause oversteer, so its controllable. With slicks and rain, I would have thought it impossible to get traction, but with my measly 300+ hp, those grippy slicks still do the job, better than RE71R's. Just wonder what Hoosier Rains would do running with 21 lbs of air.
04-09-2019, 08:29 PM
Cayman R traction control vs Cayman S PSM?
