A very interesting thread. Thank you for starting it orthojoe, and thank you to all contributors. I'm learning a lot about PSM in general and issues specific to this car. This thread has prompted me to read parts of the manual on the subject but I'm surprised at how superficial the info is.

This what a part of it states:

– When Electronic Stability Control (ESC) is switched off, sportier Traction Control is activated.
– Brake interventions are deactivated.
– The ABS remains active.

I'm confused by what they mean by "sportier TC is activated". It implies that something is "activated". What specific parts of TC are activated when ESC is turned off?

Apologies if I may have missed a previously addressed point.

 

Good question. In this case, I think that "sportier" means that "less intervention".

 

Hi Guys, I'm looking into this matter in regards to my Cayman GT4 - it has the same buttons. I couldn't quite derive my answer from the thread contents so far, so here's my question: Does shutting down TC and/or ESC disable PTV? I can't believe that there seems to be no less than five systems all meddling with throttle input and braking.

 

I asked a series of related questions of PCNA. I will excerpt a few of the questions and answers. Some good info in between the "interesting" editorial comments.


Question:

Of course we generally know (we think) what ESC does, applies brakes, retards throttle, etc when activated, but we do not know parameters etc. Thus, for example, with ESC off but TC on, does the car only regulate longitudinal tire slippage from excessive throttle, or does it also regulate lateral tire slippage from any potential cause?

Answer:

In the 1st switch-off stage ESC OFF, the system offers increased driving dynamics on race circuits by deactivating lateral dynamics control (Electronic Stability Control). This enables the vehicle to be steered around corners with the required drift using targeted steering movements and/or accelerator pedal control. The longitudinal dynamics control system (Traction Control) takes a sportier approach, high traction through Automatic Brake Differential (ABD) and active safety through Anti-Slip Control (ASR) and Engine Drag Torque Control (a.k.a. MSR) remain active in this driving mode. Page 138 of the OM provides the statement shown below. The same page also provides the statement, “There is no stabilizing brake control in either of the switch-off stages (even when the brakes are used).”

Q:

Does braking into the ABS reinstate one or both?

A:

No, braking into the ABS threshold does not reinstate ESC or TC if they are deactivated with the control switches.

Q:

Does excessive slip angle or another exceeded parameter reengage the system.


A:

No, the ESC & TC systems are not reengaged through driver or vehicle inputs except by depressing the function buttons in the center console as described in the OM. Were this not the case, the systems would reengage during use of the vehicle on our kick plate, for example, where excessive slip angle & vehicle rotation is common.



Q:

Why can’t we turn off TC and not ESC? I could see advantages there but the lack of ability to do so suggests I may not understand the cascade of the systems.

A:

If it were possible to deactivate TC (thus deactivating ABD, ASR, & MSR) but keep ESC active, the system would allow wheelspin through heavy throttle application while allowing intervention with ESC if the car starts to rotate, for example. Wheelspin does not make the car go faster, and ESC prevents the car from rotating. That takes all the fun out of it, in my opinion. It seems he wants a “burnout” mode… rather un-Porsche-like. I wonder what advantages are foreseen, as I do not see any.


I may disagree with the last answer but at least we have an answer.

 

Most loss of control is due to what the driver does with his feet. Throttle and brake, thus traction control would take priority over directional control because this is usually lost due to losing traction from acceleration or braking. Engine breaking counts here.

Since I am older and maybe not as sharp as I once was, I just leave them all on. It seems that the amount of intervention on the GT3 is so well done that max speed, which accrues with some slippage, is mostly achievable with safety nets in place. If the purpose is to increase ones ability of car control maybe a lower cost model without any of the nanny's would be more appropriate. I did experience once a drift in the damp due to slightly too much power without any intervention on my GT3 so I feel that leaving everything on is not impeding on my fun. I no longer drive flat out.

I spent some time in an older Viper once and it was an excellent training tool for this because it was quite easy to overwhelm the availability of traction with improper foot application.

This being said, it makes perfect since to have TC on with ESC off. Imagine all of the Carrera GTs that would still be around if they had a good TC system and no ESC.

 

Look at it this way, ESC controls slip at both axles and both forward and sideways. TC controls forward direction slip only and at rear axle only (except EBD, which controls front as well under braking).

FWIW, TC-only allows much more forward slip on rear axle than ESC+TC mode (so basically TC in ESC + TC mode is more sensitive than in TC only). For example, TC only did not cut torque on T-hill T11 bumps.

 

I am pretty sure PTV ALWAYS stays on. Allan

 

Good thread.

On a personal note. I had my car pretty sideways last weekend and the systems allowed for a nice correction. Heck, they might have corrected the whole thing. It was the first time I felt the car step out, and also the first time I've felt intervention in a turn. It happened in a way that I would not have caught and the counter correction might have put me into a tire wall. It was remarkable how late the intervention came, and yet how effective it was. This adds nothing to the discussion about the deactivation of TC and not ESC I realize.

 

Bumping an old thread, good info, was searching for how this works on my GT4. I think another reason TC stays on last is that the Porsche systems are more race/track oriented. This is probably how a race car driver would want it.

Related question. Will the dash light blink every time ESC is activated? In cars w/o any kind of electronic stability, the car provides you with very good feedback. Make a mistake and you get under/oversteer. With these systems, it can be harder to tell. In other words, I'd like to know how often I'm activating ESC when leaving it on.

 

It comes on for any SC or TC activity

 

Yes, it comes on both when PSM (ESC) activates or when TC intervenes.

Oops. Peter already answered this....

 

The only reason you can deactivate TC alone is to get the car out of snow, ice, mud, etc.
There is no advantage or reason to drive with TC off and ESC on. All on or all off except the above situation.
Even if you deactivate TC the ESC will work exactly in the same manner as with the TC ON.

PTV is always on. You cannot deactivate this system.

FYi: BMW has similar stages to deactivate TC and ESC regardless of their model line (sport, limousine or SUV) and the reason is explicitly described.

 

Thanks guys. I knew the light comes on, but wasn't sure if there are "minor" instances in which it will not, thus masking feedback to the driver.

My last BMW was opposite of Porsche. Engine cutting comes off with the first stage of disengagement and then DSC second. But with BMWs, the baseline traction control is incredibly intrusive. For better or worse, may people drove in the middle setting as a matter of course.

 

Did you RTFM? Or pay attention to what has been posted in this thread? Or simply write "deactivate" instead of "activate?" What you state above-- "you can deactivate TC alone" is NOT possible in the GT3. The ESC can be deactivated alone, or both ESC and TC can be deactivated, but TC alone CANNOT be deactivated.

TT.

 

Damn, that was stupid what I wrote.
I can't believe you can swith ESC off and keep TC on in Porsche. I never paid too much attention to those two buttons as I only switch everything off.
I can bet my hand that it is the other way around in BMWs. I drove 335i and M3 for a while.
Sorry!