Jetpilot

I am fired up about my first DE this weekend.

What is the correct tire pressure for 295/30/19 PS2s ?

Thanks

cello

Here's a good discussion for 19s: https://rennlist.com/forums/997-foru...-pressure.html (esp post #3 as a guide).

Note the 'correct' pressure can be in a small way somewhat manufacturer dependent as most (including me) find PS2s begin to get pretty slippery over the 40lb mark.

For the first event - follow the recs in the thread (link) provided.

Have fun!!

Jetpilot

Perfect!

Thanks

Edgy01

You really need an assistant there at the track to help you with this sort of thing. First off, get yourself a pyrometer or a spot thermometer in which they can quickly measure your tire temperatures. They should check it on the outside third of the tread, the middle and the inside third,--and do this for all 4 tires, and do it quickly. This will give you an idea of where you are with tire pressures. Use the temps. to help you to understand what happens when you raise or lower pressures. Once you get the tires up to temperature then take copious notes on what your TPs are and then allow yourself to get a feel for when you are on the edgy of the potential of those tires. When they get REALLY hot they become unmanageable.

RonCT

Nah, all you need is a good tire pressure gauge and keep your hot temperatures in the optimal range. At the track maybe 1 out of 10 of us in Black or Red are using a pyrometer and they are using it to tweak suspension settings. Get the pressures right and you'll be fine.

Do a search on "pressure track" or something like that and you'll get probably 100 posts just like yours asking for the best pressures. I don't have my track notes handy, but I think when I used to run PS2s, I was running about 38 front and 39 rear PSI hot (?), meaning about 10-12 PSI lower than that for first session depending on conditions (cold vs. warm day, rain, etc.). Do the search and you'll find your answers.

todinlaw

First you don't say what tires your are running, but lets assume, ps2. I think you should run the fronts hot about 2lbs softer in the front than rear, due to the increased wt in the rear. Next the cold temps is totally dependent on the track temps. The hotter the temp the more you have to lower your starting temp, because of the heat build up. If this is your first DE you are not going to be pushing the car or the tire. The point I want to make is how to deal with tire pressure once you get a few DE's under your belt. I would start with about a 4 to 5 lb reduction from the target Hot tire pressure. Ron makes a good point do a search and see what others who run the PS2 on a 911 found as a good hot pressure. Once you know the target, first run start out with a 5lb reduction ft rear.
The key, once you come in the first thing you do when you get out of the car is check and record all 4 tire pressure as you are checking bleed off the air that exceeds the target hot pressure. So during the day as the temp goes up and my speed is going up after every run I bleed off the air to bring it down to the target hot pressure.
Make notes. next morning check the cold pressure now you have a target cold pressure. which will have to be adjusted up/down for the days expected temp.
If you cannot get to the tire pressure just after the run, becuase your instructor is telling you how good you are, then get a buddy to do it while you are jawing. otherwise you will start losing pressure.
You are on a slippery slope my friend, if you get addicted.

MartinJ

Okay so some advice for your first few DEs.

You will not be driving the car at it’s limits early on (it will take quite a few sessions) and your first runs will focus on driving the line and making sure you are safe, as you do more runs you will build speed, hit the brakes harder and get the tires hotter…

So as others have said you will notice that tire pressure will go up during the day (as it gets hotter and you get faster). For your first run I would run pretty close to recommended stock pressure when the tires are cold (maybe stock – 2 lbs, Porsche recommends 33 in front and 39 in the rear for a C2 or C2S with up to 2 passengers), you can easily run over the sidewalls on the front tires if the pressure is to low. Once you are off the track use your tire gauge (get a good one with an easy to use bleed button) and see where you are and ask your instructor. I expect that you will let out a lb or two each run. If it is cold and you take a long brake watch those pressures and warm up the tires for your first few laps since the cold pressure will be quite low at the start of your run.

I have found that street tires get greasy as the pressures get above around 40 PSI (the fronts get hotter) and the tires get hot, I am convinced that it is the heat that takes away grip! As you learn take notes on how the car feels, track conditions (tracks get hotter on sunny days and your tires will get hotter to) and outside temp, after a little while you will end with good idea of what your target hot pressure is, I think my targets are a little higher than others on the board since my fronts often hit 38 - 40 and the rears around 43 with PS2s. When you start you will need to be at 4 – 5lbs lower than that when your tires are cold, as you get faster you will need to be even lower cold.

Remember to take a hard look at your pressures before you driving home you may need to add some air back!

mdrums

Jetpilot, I do a lot of DE's plus I also instruct. The 1st few times you are out in your very first DE you need not worry about tire pressures. Your instructor will help you out with this subject. But since you asked and if you are running stock street 19" tires check them when you pull into the pits and keep them under 40psi. You should start out at probably 30/33 depending on the track temp, weather and how fast you are actually going. I would suggest just start out at stock pressures of 33/39 and adjust from there. You 1st need to learn the driving line and braking points of the track.

Make sure your car is safe, empty out the storage areas, take out the floor mats and have your car tech inspected at a good shop. Hydrate yourself good for a few days and get a good healthy dinner and good nights sleep. Study the safety flags and look over the track map. Show up for your 1st DE with an open mind.

This is all you need for your 1st time...you are about to learn a lot about yourself and you car! I am happy you decided to do a DE...enjoy! I know you will.

Jetpilot

mdrums -

That's prolly the best advise I have been given - thanks bud !

cole328

I have same set-up and have found that 36/38 HOT is great combo

R2R

If you have the time, google Eagles Canyon... there are plenty of videos to watch and learn from! Just make sure you are ready to enjoy yourself
I should be out there in the morning with the camera, I'll make sure to look you up!

Jetpilot

R2R

Thanks for the great shots. Always good to see you.

I ended up running 34 all around and by the end of each run pressure was at 40. Perfect for me.

Merlin1

This article has been very helpful, Thanks everyone.
I am trying to do my first autocross in April and hopefully some DE events this year (got my HJC Si12 this weekend ), so I am excited.
I have always wondered as to the difference in driving style between an autocross and DE (I know that DE is at track vs a made up track in an autocross).
Secondly, do those cones not cause any damage to your car??? or for that matter any other things?

mdrums

Jet Pilot....so.....did you have fun? What did you learn? Glad everything turned out good for you.