991 RS - target hot pressures track
Discussion
Porsche911R said:
Temps are all that matters, pressures are a after effect.
Not sure why people buy track cars for >£100k and don't own a pyro, it's like pissing in the wind.
Is there any thread on this forum you cannot reply to in a condescending manner? From pistolp's profile he appears to be quite an accomplished racer.Not sure why people buy track cars for >£100k and don't own a pyro, it's like pissing in the wind.
You can't set temperatures hence his question. Jeez.
As every one has their own style and geo, how long they stay out, and how hard they drive etc etc the "what shall I set my PSI too" is a pet hate question on PH of mine.
My advice is sound, buy a pyro and on a basic level if the middle is too hot let some air out !!!
It's the best advice I can offer.
My advice is sound, buy a pyro and on a basic level if the middle is too hot let some air out !!!
It's the best advice I can offer.
Porsche911R said:
As every one has their own style and geo, how long they stay out, and how hard they drive etc etc the "what shall I set my PSI too" is a pet hate question on PH of mine.
My advice is sound, buy a pyro and on a basic level if the middle is too hot let some air out !!!
It's the best advice I can offer.
I have hear some good stuff from you, but it would sound even better if you cut out the sarcasm/insults et. My advice is sound, buy a pyro and on a basic level if the middle is too hot let some air out !!!
It's the best advice I can offer.
Steve thank you. I'll try that. I was running them way too high in which case, on balance.
As for that other idiot know it all bloke. Put a sock in it mate. This is a track day and a bit of fun. All I want is to get the car in the window, I don't need it perfect. I just want to make sure I'm not wildly off where they should be as I was having some pretty big swings in handling throughout the day as I tried different pressures. Tyre temps are useful of course but pressures are the first port of call. For starters if you've got pressures wrong you'll never get a good consistent tyre temp spread - which is what you want. It's no good just taking the middle as you say, you need to measure across the surface of the tyre for useful data. I'm not an expert on these things but you clearly aren't. I rely on engineers for this sort of stuff, people who know a little (myself included) can just confuse you more.
As for your point about it being a stupid question because of X, y and z. Well, I asked for hot pressures. That would imply to anyone who has the foggiest idea that it's at the end of a run when the cars up to temperature. It's up for whoever replies to gauge that, but there are some sensible people on here. Those were the people I was hoping to engage. Once again, thanks Steve for useful input.
As for that other idiot know it all bloke. Put a sock in it mate. This is a track day and a bit of fun. All I want is to get the car in the window, I don't need it perfect. I just want to make sure I'm not wildly off where they should be as I was having some pretty big swings in handling throughout the day as I tried different pressures. Tyre temps are useful of course but pressures are the first port of call. For starters if you've got pressures wrong you'll never get a good consistent tyre temp spread - which is what you want. It's no good just taking the middle as you say, you need to measure across the surface of the tyre for useful data. I'm not an expert on these things but you clearly aren't. I rely on engineers for this sort of stuff, people who know a little (myself included) can just confuse you more.
As for your point about it being a stupid question because of X, y and z. Well, I asked for hot pressures. That would imply to anyone who has the foggiest idea that it's at the end of a run when the cars up to temperature. It's up for whoever replies to gauge that, but there are some sensible people on here. Those were the people I was hoping to engage. Once again, thanks Steve for useful input.
I run a GT4 with MPSS and MPSC2's.
I also run 30psi hot all round and David's pyro confirmed that the car was working well with these tyre pressures and standard geo set-up.
Pyro is not as easy as it sounds because on a clockwise circuit really leaning on the car the nearside tyre edges will always be hotter than the drivers side edges and the tyres cool very quickly when cooling down the brakes and engine.
In defence of David the information offered can be very useful and in real life you don't need to worry about his bedside manner !!
Just that his way with words is sometimes marmite. David, many thanks for the loan of your pyro !!
What track day are you planning next ? We had a fabulous day at Cadwell a couple of weeks ago ... ??
I also run 30psi hot all round and David's pyro confirmed that the car was working well with these tyre pressures and standard geo set-up.
Pyro is not as easy as it sounds because on a clockwise circuit really leaning on the car the nearside tyre edges will always be hotter than the drivers side edges and the tyres cool very quickly when cooling down the brakes and engine.
In defence of David the information offered can be very useful and in real life you don't need to worry about his bedside manner !!
Just that his way with words is sometimes marmite. David, many thanks for the loan of your pyro
!!What track day are you planning next ? We had a fabulous day at Cadwell a couple of weeks ago ... ??
Well I have raced pretty seriously for 10y and the guy that runs my Ginetta G55 has won Le Mans twice. We check tyre temps before but he's obsessed with pressures. So I'm inclined to believe there is something in that. Tyre temps are useful of course but for a track day? Also you need to take them the moment you stop and preferably flat out into the pits. It's more sensitive than pressures and also more influenced by variables. Also you need the spread across all four, not easy in a road car on your own! Ambient temp, track temp also more of a factor.
Look at the end of the day people like to come across as experts. I don't know jack about this stuff, that's why I pay someone a good deal of money to look after my car.
For a track day car I don't know, other people's experience of pressures (a far more commonly measured peramterer) wools have been useful. That said if David has the ideal tyre temp spread to hand for the 991 I am all ears? Can I borrow your tyre temp gauge as well?
Lastly, regardless of temps and pressures, you still wouldn't see which way I'd gone on track. Why can't people just not be nobs. It's supposed to be a forum for people that love cars.
Look at the end of the day people like to come across as experts. I don't know jack about this stuff, that's why I pay someone a good deal of money to look after my car.
For a track day car I don't know, other people's experience of pressures (a far more commonly measured peramterer) wools have been useful. That said if David has the ideal tyre temp spread to hand for the 991 I am all ears? Can I borrow your tyre temp gauge as well?
Lastly, regardless of temps and pressures, you still wouldn't see which way I'd gone on track. Why can't people just not be nobs. It's supposed to be a forum for people that love cars.
Edited by pistolp on Friday 1st July 23:22
Not sure. I did it after getting them up to temp, or should I say pressure!!!
To be honest I just used my pressure gauge, I need to read the manual on the circuit pressure mode because I was having trouble resetting it once we let pressure out. It worked well for the first session but then it proved a bit unreliable and I was stuck in the pit queue hopelessly pressing buttons! So I gave up. I'm probably being thick.
To be honest I just used my pressure gauge, I need to read the manual on the circuit pressure mode because I was having trouble resetting it once we let pressure out. It worked well for the first session but then it proved a bit unreliable and I was stuck in the pit queue hopelessly pressing buttons! So I gave up. I'm probably being thick.
The problem with the TPM is that once the pressures drop to what it considers to be too low a starting point, it will not allow you to set a circular route (circuit).
So you have to ignore it ... go out and warm up the tyres again and then come in and re-set circuitous route. This can only be done when the car is stationary.
Once it's working it's useful and quite accurate --- I see it running up to 32 / 33 on the front nearside and 31/32 + on the other three tyres when I've set the tyres at 30 hot after two cooling down laps.
The Americans are running up to 34 psi on PS Cup 2's and maybe they just come in with everything hot to check their pressures ?? Or maybe they have sussed the TPM
So you have to ignore it ... go out and warm up the tyres again and then come in and re-set circuitous route. This can only be done when the car is stationary.
Once it's working it's useful and quite accurate --- I see it running up to 32 / 33 on the front nearside and 31/32 + on the other three tyres when I've set the tyres at 30 hot after two cooling down laps.
The Americans are running up to 34 psi on PS Cup 2's and maybe they just come in with everything hot to check their pressures ?? Or maybe they have sussed the TPM
Edited by ChrisW. on Monday 4th July 21:42
pistolp said:
Not sure. I did it after getting them up to temp, or should I say pressure!!!
To be honest I just used my pressure gauge, I need to read the manual on the circuit pressure mode because I was having trouble resetting it once we let pressure out. It worked well for the first session but then it proved a bit unreliable and I was stuck in the pit queue hopelessly pressing buttons! So I gave up. I'm probably being thick.
Thanks. I was going to try just setting it cold and then let out pressure subsequently.To be honest I just used my pressure gauge, I need to read the manual on the circuit pressure mode because I was having trouble resetting it once we let pressure out. It worked well for the first session but then it proved a bit unreliable and I was stuck in the pit queue hopelessly pressing buttons! So I gave up. I'm probably being thick.
apparently the best reset way is to switch tyres to winter setup and then immediately switch it back to summer... then viola.....
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