track day tyre pressures
Discussion
probably an FAQ but can someone please advise on ball park tyre pressures for a boggo standard 996 C4 running 17" P zeros. The PCGB says..
"Generally, Porsche tyre pressures do not need to be increased for track use. In fact for some models (later 911's in particular), you will need to lower the rear pressures, perhaps by 6-8lbs or more, depending how hard the car is being driven and how much heat is being generated within the tyres."
so that would be 32 to 34 on the rears? but they don't say hot or cold!
"Generally, Porsche tyre pressures do not need to be increased for track use. In fact for some models (later 911's in particular), you will need to lower the rear pressures, perhaps by 6-8lbs or more, depending how hard the car is being driven and how much heat is being generated within the tyres."
so that would be 32 to 34 on the rears? but they don't say hot or cold!
Mark,
There isn't any hard and fast rule, (no pun intended). Generally, try keeping tyre pressures at cold setting, when tyres are hot, if you see what I mean.
If cold pressure is say 36, then lower pressures to 32, warm tyres up gently, e.g. don't go out on the first lap and overheat tyres, take it gently. Then check pressures, and adjust to cold (36) pressure when tyres are hot. You will then have to adjust to suit you driving style, e.g. like to slide at the rear, increase raer pressures (less tyre contact with the track surface).
Of course, hot/cold days will also affect what pressure suits.
So, lower pressures, try keeping cold setting on hot tyres, and adjust to suit yourself.
This assumes dry track, if wet, then higher pressure (open tread blocks to clear water) will be required. Don't use higher pressure on dry track, the tread blocks will haet and move about more, resulting in less grip and squiming.
There isn't any hard and fast rule, (no pun intended). Generally, try keeping tyre pressures at cold setting, when tyres are hot, if you see what I mean.
If cold pressure is say 36, then lower pressures to 32, warm tyres up gently, e.g. don't go out on the first lap and overheat tyres, take it gently. Then check pressures, and adjust to cold (36) pressure when tyres are hot. You will then have to adjust to suit you driving style, e.g. like to slide at the rear, increase raer pressures (less tyre contact with the track surface).
Of course, hot/cold days will also affect what pressure suits.
So, lower pressures, try keeping cold setting on hot tyres, and adjust to suit yourself.
This assumes dry track, if wet, then higher pressure (open tread blocks to clear water) will be required. Don't use higher pressure on dry track, the tread blocks will haet and move about more, resulting in less grip and squiming.
Try 36 HOT all four. If the rear feels a bit squirrely (and just be fecking careful at Goodwood....), lower to 34, even 32 -see how it feels.
Forget times, you're on a track day -that's when accidents happen.....
Above all, enjoy!!
Melv
>> Edited by Melv on Thursday 27th November 17:59
Forget times, you're on a track day -that's when accidents happen.....
Above all, enjoy!!
Melv
>> Edited by Melv on Thursday 27th November 17:59
On my 996tt the recommended cold pressures is 36/44. I tend to drop the tyres to 32/40, do a few laps, the tyres warm up and I drop them back to the recommended cold pressures of 36/44 again. I continually do this immediately after each session. Before lon gwhen you end each session you'll be finisshing with the same pressures give or take a lb.
DAZ
DAZ
Thanks guys, and you are quite right, should have qualified my comments about times.. no timing allowed of course. I was just curious. On the day, its all down to weather and how hard you want to push. On this occasion I was intending to put in some nice relaxing laps and 1.35 is quite quick enough for Goodwood in the real world (as opposed to down the pub afterwards world). In fact, thinking back over previous experience of various Porsches at that circuit, I doubt there are many that would do much better.
A about 2 years ago I was following about 200m behind - a GT3 +cage who was flying. I could close up a bit in the bends but he would streach away on the straights. both keeping station.
I was in my Superlight R and have not come across a car who I could not make any inroads into at Goodwood. A friend who was timing me from the pits(dont tell) said I was going around in 1.32.
So the GT3 was flying and I was going 9.5/10 ths. I hit max speed for my 7 approx 140 ish.
So if you can go around quicker than that - I will take my hat off to you !
But dont race, have fun.
I was in my Superlight R and have not come across a car who I could not make any inroads into at Goodwood. A friend who was timing me from the pits(dont tell) said I was going around in 1.32.
So the GT3 was flying and I was going 9.5/10 ths. I hit max speed for my 7 approx 140 ish.
So if you can go around quicker than that - I will take my hat off to you !
But dont race, have fun.
160 - 165mph on the Lavant straight? Hmm, may be it was an exocet missile cunningly disguised as a GT3?
Well, Saturday was the kind of disgustingly wet, freezing, horizontal rain day that you expect at Llandow, not Goodwood, and I was mildly amused to overhear several of the max power boys opining that the flash git in the C4 (so that would be me then :confused) would be comprehensively outrun by the Imprezas - its a whole different language, something to do with 22B RA WRX STi P1 type vI version 17.
Flash? If only they knew.
The kitty litter collected 2 Imprezas (one totalled), a couple of Novas, an escort and a sierra (both race prepped). It was an eventful day for the marshalls.
And as for time? No timing allowed.
Quote of the day goes to a Cosworth (sierra!!) owner, who, notably, wasn't driving. "..course, I can do an 86 sec lap here and that was with just 500bhp, imagine how quick I'll be with 558bhp."
he he.
Well, Saturday was the kind of disgustingly wet, freezing, horizontal rain day that you expect at Llandow, not Goodwood, and I was mildly amused to overhear several of the max power boys opining that the flash git in the C4 (so that would be me then :confused) would be comprehensively outrun by the Imprezas - its a whole different language, something to do with 22B RA WRX STi P1 type vI version 17.
Flash? If only they knew.
The kitty litter collected 2 Imprezas (one totalled), a couple of Novas, an escort and a sierra (both race prepped). It was an eventful day for the marshalls.
And as for time? No timing allowed.
Quote of the day goes to a Cosworth (sierra!!) owner, who, notably, wasn't driving. "..course, I can do an 86 sec lap here and that was with just 500bhp, imagine how quick I'll be with 558bhp."
he he.
I allways try to stay clear/ get moved to another group if there are too many max power group. Goodwood is fun, plus there are only 5 cars on at a time so you can stay clear.
How/where did the Scooby total himself?
Im surprised the cossi owner couldnt have done it under the magic 1 min mark.
on the back straight I bet even the GT3 was not above 155mph. (btw) (unless slicks)
Glad you had fun. and left safely. The wet track day is good as the limits are lower, and you can get to push the car at lower speeds and thus not have such a big off (hopefully)
I took my 996 targa there and was nowhere near 1.32, my mate was in my 7 behind me and was flying past. I got up to 140 in the targa on the back straight. The limiting factor was the tyres/grip/weight on corners, I just coulnt go around as fast at the 7 with 032rs
The PSM was very good, gently tugged me back onto the black stuff when the car was sliding after being too fast in a bend. - not a big off, but an off nonetheless wouldhave happends. Car sliding all 4 wheels, couldnt put any more lock on gently drifiting wide, the drif starts - I was a passenger just holding it, anything I could do - break all 4 wheel, stear, let off power would have spun it. The PSM kicked in and breaked the front right, rear right alternativly and got me back on track. Wonderfull.
How/where did the Scooby total himself?
Im surprised the cossi owner couldnt have done it under the magic 1 min mark.
on the back straight I bet even the GT3 was not above 155mph. (btw) (unless slicks)
Glad you had fun. and left safely. The wet track day is good as the limits are lower, and you can get to push the car at lower speeds and thus not have such a big off (hopefully)
I took my 996 targa there and was nowhere near 1.32, my mate was in my 7 behind me and was flying past. I got up to 140 in the targa on the back straight. The limiting factor was the tyres/grip/weight on corners, I just coulnt go around as fast at the 7 with 032rs
The PSM was very good, gently tugged me back onto the black stuff when the car was sliding after being too fast in a bend. - not a big off, but an off nonetheless wouldhave happends. Car sliding all 4 wheels, couldnt put any more lock on gently drifiting wide, the drif starts - I was a passenger just holding it, anything I could do - break all 4 wheel, stear, let off power would have spun it. The PSM kicked in and breaked the front right, rear right alternativly and got me back on track. Wonderfull.
scooby barrel rolled (twice) at StMary's. St Mary's was the favourite place of the day to have an off, although there were some spins at the chicane and some straight ons at Madgwick/Fordwater and Woodcote. So.. just about everywhere then!
and, you are so right, the key to Lavant straight is Lavant corner, which is why IMHO, a caterham will always be quicker than a GT3 at that circuit.
and, you are so right, the key to Lavant straight is Lavant corner, which is why IMHO, a caterham will always be quicker than a GT3 at that circuit.
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