Well I just tracked the GT4 today in a Porsche club event.
30 cars running around a tight technical course. Most of it is in 2nd or 3rd gear with a standing start and flying finish.

Previous car was / is 987.2 Cayman S PCCB PASM LSD and various bolt ons like exhaust, plenum, RSS links and LCAs'. [Usually this car is in top 4]

Sadly with the 20" OEM tyres (Dunlop Maxx Race) they were very slow.
A guy in a 987.2 PDK Boxster S with 18" cheater tyres smoked me by 6 seconds or so (3 lap run), and considering Im usually faster than him in my 987.2 S with the same tyres on, it was all rather dissapointing.

GT4 boggs down a lot coming out of a tight 90 degree bend due to the flat spot in the middle of the torque curve. Worse than the 987.2

Launch was ok but did get some dreaded wheel hop. Man I cant beleive this car still does that. 987.2 with RSS Semi Solid links is much better.

Turn in was good with almost no understeer. Camber -2 front and rear, bar setting original. Same performance as 987.2.

Power oversteer was good at the 5% slip angle. Well controlled and well adjusted by steering angle and throttle input. Virtually identical to my previous 987.2 S, but PSM threshold limits are a tad higher in comparison which is good.

First time with a car with TMPS. This drove me freeking crazy. As usual I have to deflat the tyres when they got too hot. Well having this thing bring up alarms all the time and no proper way to stop it was madening. Esp near the braking point the dash lit up red and put me off. Grrrr.

Brakes, ok so I got spoilt with PCCB on the old car, they are sooo much better.

Ok, so I had to do some stuff to make the 987.2 a much better car, but it was really suprising to see that the GT4 was a LOT slower and the added top end power did not make up for lack of ultimate rubber. If and when I can get the same cheater tyres on all bets are off.

 

Maybe, you should practise a little more when you got smoked by a 987. The Dunlops are not that bad, but they need higher pressure to work optimally (what most people don't know, so they fill in 2.1 bar which destroys the Dunlop - recommended is at least 2.5).

 

Did you put TPMS in Circuits mode and set desired pressures there? You can't set anything below 27, but it may help.

 

Thanks for the analysis. I recently sold my very well setup 987.1 and all of my buddies are telling me how much faster I'll be in a GT4. I'm expecting about what you observed, its not horsepower. I'm planning the 18" wheel option but not initially. I was able to remove TPMS using a Durametric Pro version on my 987.1 and am glad I did.

 

Pretty sure the tpms has a track setting.

 

The issue is that you can easily experience a 10+ psi rise when tracking. The TPMS circuit won't really let you go low enough in order to achieve that sweet spot hot pressure while on track. That in turn will give warnings that some will consider annoying.

 

On my 981 GTS I got the warnings to shut up by telling it I was using comfort setting for the tires. Maybe the word was not comfort, but it was some word that seemed off to me and once I clicked yes the car shut up and let me do whatever I needed with the tire psi after that.
I am tempted to keep my 15 GTS just to see how much different the times really are with me driving it compared to the GT4 I will soon be getting.

 

If it is like the GT3 after a session bleed the tires to your target hot pressures. Restart the car and set these pressures in circuit mode as new target pressures. Annoying thing is after each session when you restart car you must state car in circuits mode otherwise will recalibrate which takes too long.

 

axle hop is reduced with PASM set to sport. Did you use the launch control procedure?

 

What is this launch control procedure? I think people who have visited the porsche center in Atlanta and did some launches were experiencing wheel hop and that the instructors were saying it's normal.

 

How much power was your 987.2 putting down?

I actually thought the 3.8-L in the GT4 (and 991.1 S) had a relatively impressively flat torque curve for a naturally aspirated, high-strung 6-cylinder... But of course I haven't driven the thing yet, so what do I know.

 

Practice is not the issue here, 7 years tracking and many track records.
The Dunlops are road tyre and for a road tyre they are pretty good, but they are far from an R-spec tyre.
Tyres are still looking good.

Dont seem to have this mode. But "Circular" mode did come up. At the moment the TMPS looks messed up with 2 left tyres saying "Targ". I need to study up on the TPMS controls and sort this out.

Correct, I had that error as well.

Good idea.

Of course ran it in Sport mode.

Not sure on the 987.2 power as I cant Dyno it due to the PSM 4K RPM limiting. My guess is around 310 WHP. My older 987.1 did 303WHP.
Note the Torque curve taken from the GT4 service manual below. I know people have measured this themselves, but this curve shows a nasty TQ dip would have been measured just the engine itself.

I really really wanted the GT4 to be the car I did not need to modify, but allas it looks too watered down for me.
Also take the suspension, I could not get enough neg camber at the rear so had to change the rear toe links already. Its just nuts.
Looks like I'll have to do these mods all over again....maybe..
Ok so rant over for now..



GT4 TQ curve from GT4 service manual.

 

I am pretty sure the GTS is a formidable car but it does not make sense it would be way better than a GT4 hence why Porsche even made a "special" track variant. I think you just need some getting used to it.

 

I don't think you properly tracked the car at all, you need to take some proper driving school. The GT4 is awesome and love mine so much. I have no idea what you are talking about. Porsche GT4 is amazing no modifications necessary

 

So, "Gazz" (being an Australian by birth, I presume you are a Gary, or Garry), you sound like you came here to bitch and moan about your GT4. I suggest buckle up, mate. Your GT4 is potentially a far better car than your 987.2, so be patient, and figure it out. There's nothing worse than a winging Aussie, especially from Perth (my home town.)