Wild Weasel

Hey all,

How can I tell when PSM has stepped in and helped me along in minor ways? I'm talking about when there's no light on the dash and you're not feeling the brakes doing their witchcraft or the throttle cutting out (for TCS)?

I'm not about to turn it off, so just turning it off and seeing if it feels different isn't an option.

Is there any signal on the CANBUS or something that can be picked up by a data logger?

Tim the Engineer

The ABS is not generally connected to a data logger.

If you are on the track, the rear brakes will be really hot and give off a burning smell after a session if PSM have been active. Don't touch them to find out, though!

You can turn the PSM "off" via the switch and see how it drives. Be cautious at first, but you will readily feel the difference. The PSM, unless you de-energize the electrical circuit (like I do on my race car), does not actually turn off.It just activates at a higher threshold.

In general, the PSM is more active than we think, using the rear brakes to correct trim around the track. If you have a data logger, you will notice a dip in speed through corners.

ProCoach

Actually, most cars with later-gen (2009 on) ABS show wheel speeds, which shows ABS actuation, and most cars 2012-on will show individual wheel brake pressures, even on something as simple as an AiM Solo.

Some cars show TCS and PASM status over the CAN, and you can see a direct correlation between driver controls inputs (hands, feet, rate of change) and the actuation of the nannies.

I use this capability frequently to help hone intermediate and advanced drivers to approach the loss of traction more gradually so that they don’t trip (or just barely trip) the thresholds of PASM and/or ABS.

Great discussion!

Wild Weasel

Interesting! My car is new so I imagine this stuff is in there. I just need to get access to it.

I have basic data through a Garmin camera I got last weekend. I haven't had a chance to really review it yet but on the first video I made I noticed that there are times that show both the gas and brake being used together. That's definitely not me doing that so I'm wondering if the PSM doing something with the brakes is showing up in the OBD2 data stream as brake activation.

I'll try to find the time next week to look at it more in depth. I only noticed it happening and thought it was odd. I haven't had the time to pay attention to when it's happening and speculate about why. I expect the auto-blip when shifting likely shows this behaviour too.

ProCoach

What year and model? The OBDII stream used by genetic readers is typically not refreshed quickly enough to be an accurate representation of what happened, but it can give you some idea. A little more money can get you some pretty powerful (and more accurate) equipment...

User 52121

I have this exact same question. Your post strikes at the heart of something that's bothered me for a solution for a few years now.

2013+ models - the PSM is almost always engaging in some manner. And unless you're in a "GT" model (GT2/GT3/GT4), even with it "off" it's not completely off.

I've owned a couple 981s, driven several more on track along with several 991s and ridden right-seat with even more as an instructor. With PSM "on" - you still have to get the car pretty out of shape before the light comes on. It's not obvious it's helping until you run the same lap with the PSM off.

Frankly it's impressive. PSM on, the car just goes where you point. You're almost oddly disconnected, kinda like playing a video game with a gamepad. Point the wheel, go WOT, and it just goes. There's no muss, no fuss, the car just stays surprisingly flat. Even in cases where I'd *expect* the car to start to feel light - a little pavement undulation I know exists (because MY car, a 987 with the yaw sensor cut, or even my old 944, or the many years from 2 wheelers) - the PSM car just glides over it as if it doesn't exist. "Video game vs Simulator" is the best way to describe it.

To answer the OP's question based on my own knowledge - with a CANBUS data logger, at least on 987.2 and newer vehicles, you can track throttle PEDAL vs. throttle PLATE. So you can tell when the PSM tries to cut power - pedal is WOT but plate rolls back. But as far as the other stuff intervening - individual ABS channels doing it's thing, PTV engaging, I don't know. With my SoloDL on my 987.2 you can't see individual ABS channels (to my recollection anyways). But then the 987's PSM is "all or nothing" much like the older cars. If it engages, it cuts the fun abruptly. The newer cars, it's very gradual.

Otherwise - how to tell? Turn it off. I'm very cautious of who I tell to do that. Some good friends I have, who I've helped coach, I've encouraged them to turn it off early, BEFORE they get to a speed point on track where they can really get into trouble. Feedback has always been along the lines of "Holy sh** the car moves around a LOT!" But be careful. You might have missed a few lessons along the way that you'll need to learn. Drop down a run group. Back your pace off 50%. Relegate the event in your mind to "I'm going to be slow but I'm going to learn." Then turn it off. And proceed carefully. The more experience you have? The more careful you should be.

Take say, Road America. Maybe with PSM on you're able to run a 2:40.0. A respectable lap for a street car on a street tire. Car feels great, flat, stable, no drama. However, there are lessons learned at 2:45, the car starts to move, wiggle a bit, etc. The lessons you would have learned, progressing through the 2:45 barrier naturally, dealing with and countering the wiggles - you didn't learn because PSM did it for you. Suddenly you decide to turn it off at your 2:40 pace and expect to RUN that 2:40 pace, and the little wiggles that were covered up at 2:45 - are BIG wiggles at 2:40. And you might not have the skills to catch them.

I guess, my advice? If you want to cut fast laps, get bragging rights, and don't care whether it's YOU or the CAR doing it? Leave it on. It will ultimately cover up bad habits and let you progress to a pace you otherwise wouldn't obtain, and skip over key lessons usually learned in between. If you want to learn, and become a better driver, even if it means fewer bragging rights on lap time? Turn it off.


My 2 cents.

Wild Weasel

That whole thing is a FANTASTIC post!! Thank you for that, as it pretty specifically addresses everything that's been running through my mind.

Firstly... I'm driving a 991.2 GT3, so the car is way beyond my capabilities as a driver but it's all I've got and I'm obviously not going to give it up. It's way too much fun. Now... you'd think that if I can have a new GT3 then I could certainly get something else to use but I can't. I simply don't have the room to keep another car. I'd love to pick up a 944 or something to try at the track but it's just not in the cards.

I've been doing DE's for 5 years now and not once have I considered turning off PSM or TCS. I think it's time I re-addressed that decision from a different standpoint though. I'm not oblivious to what the car is doing. If you covered up the light on the dash, I could tell you any time it would have come on. As you guys know, things have got pretty out of shape by the time that happens so I've been of the opinion that there's no point in turning them off since they're not hampering me and when they do something, me and the car are quite in agreement that I needed help at that point.

Now though... I'm realizing that it's doing all sorts of stuff I wasn't aware of and the only way to know what that actually is will be to turn it off. So it would seem that I have to turn it off to learn to drive better and just then have to be REALLY careful not to get into those situations where I would have needed it.

I guess my plan for next year will be to turn it off and then drive as though it's raining. Tiptoe around and add speed little by little until I see where things get a bit off.

A few years ago I took a friend for some hot laps in my 981 Boxster and he had a good laugh after and told me he thought I was "electronixing" around the track. I found it amusing but also, since there weren't any lights coming on and I wasn't feeling anything, I mostly dismissed it as just using the car as it's meant to be used. I mean... PTV does it's witchcraft to make you faster, right? Not to bail you out when you've made a mistake.

At my last DE I was told by an instructor that he feels the car doing things it shouldn't be doing and that it's helping me along. That's really what prompted this post in the first place. I know he's right. I just don't know what to do about it. The obvious solution... which is to turn it off... seemed like a terrible idea. So I figured that looking for ways to know when it's doing it's thing and then trying to drive in a way that prevents it would be the way to go.

Now I'm thinking the obvious is the only viable way. Turn it off. Be really careful.

certz

Another thing you should consider given your experience and your car is hiring a driving coach. Unlike the average PCA instructor, they will be not just be telling you that you are leaning on the nannies, they will be instructing you how to not get to that point. There are several good ones that frequent RL and this is a good resource: http://www.mvptracktime.com/id95.html Not sure where you are, but I am sure people can recommend coaches close to you as well.

Wild Weasel

Honestly... I feel like we have really good instructors in my region. I'm in Toronto with PCAUCR. In this particular case I didn't really get much to work with but it was a unique case. Next year I'll work on this and then see where I'm at. I've got other stuff to work on as well that I got from a different instructor in an earlier session and I feel like I was making good progress on that by the end of the weekend.

If I ever get to the point where I feel like I'm not getting any benefit from the instructors we have... well... I'll be quick enough at that point that it won't matter and I'll just be running around for fun.

I mean... I'm never gonna be a pro. At some point I'll just be good enough, right?

ProCoach

I agree with Wild Weasel.

You have a marvelous car. An exceptionally powerful and well balanced super car. You've been driving for five years. Kind of surprised you haven't turned it off (well, down, you can't turn them completely off) already.

THERE IS NO LIGHTNING BOLT COMING DOWN FROM ABOVE TO SMITE YOU IF YOU TURN THE NANNIES OFF (DOWN)!

NOTHING SUDDEN WILL HAPPEN UNLESS YOU DO SOMETHING, SUDDENLY!

There, got that off my chest. Feels better now.

A simple AiM Solo 2 DL with a reversible direct connection to the car can tell you not only the difference between your accelerator pedal and the throttle butterfly, but also ALL four wheel speeds and ALL four brake pressures, all the way around the car.

Plus torque delivery figures, engine output calculated and all kinds of other things, IF you want to know those things. I use these tools just to define objectively, and validate against the driver's "butt-dyno," what is happening and when. What you have won't do that.

User 52121

Seconded.


I often tell n00bs, "If you've never picked up a basketball, you don't need to hire Michael Jordan to show you the basics of dribbling and shooting. The kid down the street can do a pretty effective job of that." And I still stand by that.

BUT.... it can be pretty damned impressive what a "Pro" coach can tell you. My first ever experience with a real coach was at PCA Road America many years ago. The coordinators picked up the tab to have David Murry available in the classroom for anybody who wanted to come in and ask advice. I brought in my GoPro footage, from my camera which was just suction-cupped to the windshield. No data or anything, just video. I knew where on the card my fastest/best lap had been, and played it for him. A single lap... he spent an HOUR with me and picked it apart, bit by bit. Honestly it was amazing. From that point forward, my eyes were WOW open about the advantages of a "real" coach.

That's not to knock the PCA instructors. Hell I used to be one before I moved on to coaching with other groups. There are some really talented guys out there who are also excellent instructors for PCA. And "those who can't do, teach" is also true. I've seen some fellow PCA guys who are NOT fast on track but are pretty damned good coaches.

So that said - 5 years of experience? You might really benefit from a day with a big gun. Most of them allow you to split the day with another driver too, so keep that in mind if you have a friend who's curious about it.

Even the real life pro's have coaches on hand. Never stop learning.

Truth. Tho of course ProCoach here has forgotten more than I will ever know about coaching.... He's A+. You're not going to explode into a ball of flames or tumble end-over-end once you hit that OFF button. I find with most students I teach (I lead classroom for LAPS Inc. now along with 2 other storied drivers) that the ones with fear? Are the ones that do the best. That fear will keep you safe. It will keep you on the right side of respect for your car.

You have a LOT of car. If I consider all the 2-wheel stuff I did when younger, I've been in some form of racing for 30 years. I've co-driven arrive-and-drive cars with current podium-finishing Pirelli World Challenge drivers (and gone consistently faster than them in a race.) Not boasting - but setting the stage: dude, I personally would be nervous trying to hustle a GT3 at pace. It's a lot of car. The PCA Road America coordinator (Keith Clark) bought himself a 997 GT3 RS a few years ago. He was already an accomplished Club Racer. I'd asked him, "You gonna do a DE or two with it?" to which he replied, "Hell no - that car scares the sh*t out of me."

I "get" not accepting the call to buy something else. Even with unlimited funds, we sometimes just don't have the space or wife points. Nothing wrong with wanting to continue learning in the GT3 - it's a killer machine.

But I think it's necessary to truly accept that it's a LOT of car, and it WILL cost you "rate of improvement". You'd get faster, much more quickly, in a slower car - just because the limit of the GT3 is so "out there", where the laws of physics still rule the land, and getting out of shape can have much larger consequences. At some point, the computers will just do this: ¯\_(ツ)_/¯ Just ask Certz above - he's had at least one student manage to get past PSM so quickly he did a complete spin and (I think?) tapped the wall in T8 at Road America...


Ok that's interesting (bold above). You mention "reversible direct connection" - is that something special vs. just the typical CAN version SoloDL? I'll have to crack an old log back open and see if it's really in there.

certz

I can't believe I am going to say this, but Matt DiStefano (RL member jdistefa) is a great driver and instructor in your region - also out of Toronto. OMG my keyboard just caught on fire, Matt if you read this it's not me, it's the equipment, love you man

ProCoach

Normal connection but using Posi-Taps, Add-a-Fuse and ground eyelet. No tools required.

Remember, the CAN profiles for these cars are constantly updated. So older ones didn't necessarily get this info, but in RS3 with the new S2DL, I checked just now and you can get ALL you need, including all the above, from a 991.2 GT3 and RS.

User 52121

Interesting. Does such an update exist for 987.2 and original SoloDL?

ProCoach

+1 for Matt DiStefano!