Track Use

[oldtimer]

Does anyone use their 997 / 997S regularly on the track , and if so what modifications have you done ? eg tyres , setup of suspension , camber etc

 

[Geoff_Fields]

I use my 997S for track days and have the following mods:-
6 pot 350mm front brake upgrade (as GT3 MK2)
Front strut brace
Extra set of wheels with Pirelli Corsa tyres
My car is on factory sport suspension -20mm with LSD. I believe adding a little more negative camber would be benificial but have no plans to do so for the moment.

 

[david_yorkshire]

Geoff -can you tell any difference with the strut brace (I assume its front) ?
Done 3 trackdays sofar with the S - loving it !
tyre pressures (pzero) much lower than road, (29psi all round cold, I think) made a massive difference - this was advised by Parr onsite.
David

 

[Geoff_Fields]

Re: strut brace - To be honest I don't know because the brace was fitted before first track day use.
Re: tyre pressures - Yes, lower pressures required. I find reducing to cold road pressures for track hot gives good results.

 

[Julio Geordio]

Tyre pressures - that's interesting. I'm sure this is going to sound like a schoolboy question, but how do lower tyre pressures work better on a track? I'd have thought you'd roll about a bit more, although I guess that there's more tyre contact with the surface.

 

[johnag007]

Have done a couple on my 997S also. Change the geo, they are set to understeer, you end up destroyed the tyre wall (I just have last week anyway). Parr or JMZ have a wealth of experience and it is not that expensive (the rest below is far more!).

Tyre pressure is a key requirement, on my PS I was told 32 + 36, normal road conditions 34+40. Make sure you inflate them back, I had to leave quickly at Brands and found myself driving a gondola back to London. You can change to Cup tyres, but I prefer to have a homogeneous setup with no understeer and a solid car rather than outright grip / lap records. Clearly I will say the opposite in about 6 months when I want to upgrade again!

I do not like PASM that much, but this is me, I am therefore fitting progressive springs, decided to see what difference all this makes before fitting struts/...

Brakes are fine, changing my pads to Pagids just to try, puttting on breaded hose and replacing the brake fluids. I can always fit larger ones in the future.

Anyone know whether you can retro-fit the LSD by any chance?

 

[johnag007]

Regarding tyre pressure, using them on track means the air heats up immensly. You end up with an over-inflated tyre (on mine before I knew what I was doing it went +4.5psi), you will damage the sidewalls since they are over inflated, and find that you will squidge accross the track and the tyrewalls give way depending on weight distribution. The 1st time this happens is really weird, like driving on gum or something.

 

[Guest]

Do you need to change the Geo before dropping the tyre pressures? I thought that raising the pressures was a way of protecting the tyre walls (from rolling under the rims)

 

[johnag007]

The point is not to drop the pressure outside a circuit, but to compensate for the increase during circuit driving so that they run at "normal pressure". If you over-inflate or the air inside them warms up substantially (same thing), it is like a balloon, you will inventually put too much pressure on the tyre walls and they will deform. When they do they roll around the rims and you get on the circuit a skidgy gummy feeling. Oh and you destroy the side walls also!

 

[Guest]

Thanks for that.

Is there an ideal hot running pressure that I should be aiming for?

 

[Andy Rodgett]

The latest 911 & PW describes a 997RS improved by JZMactech for track days by attention to camber,wheel toe, ride height & corner weighting. I had my 911 SC lowered and corner weighted for road use many years ago which transformed the handling - has anyone done this for their 997 & road use?
Andy

 

[johnag007]

If you wait until the 29th I will answer, Parr is doing all this on my 997S

 

[Andy Rodgett]

Look forward to hearing how you get on - should truly be a junior GT3!!
Andy

 

[david_yorkshire]

I did - but I need the rear seats;
Wish I had the money for both !

 

[Gary C]

ORIGINAL: johnag007


Brakes are fine, changing my pads to Pagids just to try, puttting on breaded hose and replacing the brake fluids. I can always fit larger ones in the future.

Humm, not sure I like the sound of this modification, don't the crumbs make the disks squeal ?

but I suppose some hot toast to eat after a few laps is nice.

 

[johnag007]

Humm, not sure I like the sound of this modification, don't the crumbs make the disks squeal ?

Sorry, mother tong is French, I can express myself much better in that language...javascript:void(AddText('[]'))

 

[Gary C]

sorry, did'nt mean to poke fun, Just found it amusing

 

[Andy Rodgett]

What do the regular track day users suggest re oil level ? Should the dashboard reading be to the top fill line or below in case of surge during cornering? I have a Millbrook day coming up in July!
Andy

 

[Geoff_Fields]

One segment down on the level indicator, definately not overfilled.

 

[oldtimer]

What Geoff997 said is right - the worst thing you can do is to overfill, its better to have something half way up the distance between dipstick markings. Porsches carry a lot of oil - you are not going to run out on a track day !
Have now done Donington and Oulton Park this year in the 997S. Running Pirelli PZero Rosso's and trying to keep pressures at 2.2 front / 2.6 rear or 33/39 in old psi units as per manual for 19inch tyres. I think that the rear is very sensitive to pressure - my car felt better with 44 psi than 39 - maybe just what I'm used to.
The Rosso's are fine but feel a bit soft on track , think stiffer sidewalls would be better. Standard OEM pads do not have same 'bite' as Pagids , I was having to brake earlier at Oulton than I'm used to. The power's good , and the 6 speed box is much better than the ancient 5 speeder in my other car.
someone should redesign the sport chrono user interface - you have to work the OBC lever as well as press the PCM knob and look at 2 different readouts while trying to keep the car on the black stuff - not fair to pensioners ![]