Mike in CA

The manual does speak to the relationship between temperature and pressure and how the TPM race circuit mode is useful for monitoring pressure as the tires heat up, so maybe that's what the article you remember was referencing, but there is no actual tire temp function.

R.Deacon

Mike, on my 997.2 targa 4s I can set the tpm to display actual psi at each
corner constantly as one is driving , is that not possible with is new car?

SamFromTX

Well, yes and no for track TPMS. It will depend on how you handle track tire pressure. If you follow the recommended routine, which is drive with normal or near normal pressure then gradually bleed the pressures as the tires heat up, it will work fine. If you do what I do, which is to start with low pressures (18-20 psi), it won't work as track mode won't read if the pressures are below 26 PSI when you set track pressures. Once my tire temps and pressures come up to desired levels, I am already giving it my best and am unable to reset while driving. So that function, while really nice, doesn't work for me. I too read before the car was released that there was going to be tire temp readout but that proved to be a rumor.

The electric brake has a **** feature programmed into it. If you are driving real slow and for some reason, you open the door (say, to try and clear a tight obstacle), it will set and stop you cold. You may be able to manually disengage it then but it's a real pain feature.

SamFromTX

I did get a fraction more lateral Gs that I never pictured. Your numbers are awesome but my braking Gs will never reach yours because I have a ton of negative camber, decreasing my braking ability. I'm good with that because I more than make up for it in corners. Those numbers for lateral Gs (1.1+G) are all greatly exaggerated, though, if compared to real measurements. They reflect occasional lateral slip from bumps and subsequent sudden grip.

reidry

Is the electric e-brake actually a separate actuator and brake actuator or does it just override the brake system and apply pressure in the lines to the main rear brake calipers?

If the system is separate, I am sure it would be temporarily or permanently disabled.

Ryan

R.Deacon

Sam, can one drop tire psi to 26 psi and have a read out of that before starting
a track session ( while tires are cold start of the day) head onto the track
leaving the TPMS display on will it continue to read out actual PSI as you go?
With mpsc's I ve found once they get north of 36 Psi they start getting greasy
optimum hot #"S 32-36psi

SamFromTX

I don't know the answer but I suspect it is not separate because when you apply the e-brake with your foot on the brake pedal, the pedal sinks noticeably.

SamFromTX

Yes. If you start at 26 and apply track setting, it will read and update pressures as they change. Another reason I don't set track PSI readout is that I like to monitor coolant and oil temps instead. For me, I found 28F and 29-30R worked best but it will definitely depend on one's driving style and preference of tire feel.

R.Deacon

Sam
thanks ,
On the electric parking brake is only engaged if you activate it ? In other words it doesn't engage on it's
own?

SamFromTX

Correct, UNLESS you open the door with the engine running and when stopped in any gear but P.

0Q991

Ah--yes, that's likely it! Thanks, Mike.

R.Deacon

Thanks for the clarification , Maybe the e-parking brake has its own fuse
which one could pull to disable such a useful feature for track car, a thought.

Mike in CA

I'm 99% certain that the electric emergency brake is a separate unit from the main service brakes. Tim has that great Technical Information book for the car. I'll bet it's shown in there....Tim?

Also, after reading about the pedal drop in Sam's car I went out, started mine up and tried releasing and setting the e-brake several times and could detect no change in the pedal position. I can't explain the discrepancy with what Sam experienced.

I've never tried the "****" feature, but one can't release the e-brake with the door open unless the service brake is depressed so the two are obviously related.

It is possible.

BTW: There is a separate fuse just for the e-brake button....

MaxLTV

Oh, yes, that pisses me off so much on my Cayanne - paying at parking garage, if you take off seat belt and open door for more reach, parking brake engages without notification and does not disengage when you proceed driving. Made me look like a noob in front my parents - my dad reacted right away, "remember how I taught you to drive, maybe we need a refresher" This feature has no place in GT3.

MaxLTV

Yes, it's exaggerated, but not drastically. I was getting almost 1.5G sustained on another device. It's a combination of sticky tires, good suspecsion and favorable banking of turns. Banking does wonders for G forces (and makes by back sore afterwards).