GTS 4.0 track tyre pressure / low pressure warning
Discussion
I did Brands Hatch last week on a hot day and compared to normal road settings, pressures went up by 8 or 9 PSI. I run 33 PSI on road, so that meant it went up to 41-42 which was obviously (?) undesirably high. So I then dropped them to about 28 cold, so that on track I was running 36 or 37.
But that meant I kept getting the rather annoying low pressure warning repeatedly for about half each session.
Car is on the P-Zeros it came with from the dealership.
(1) Can the warning be turned off?
(2) Is my experience (pressure going up 8-9 PSI on track) the same as other people’s?
But that meant I kept getting the rather annoying low pressure warning repeatedly for about half each session.
Car is on the P-Zeros it came with from the dealership.
(1) Can the warning be turned off?
(2) Is my experience (pressure going up 8-9 PSI on track) the same as other people’s?
If you push the stalk forward on the TPM menu, do you have the option to set race track pressures? (This might just be a GT4 thing). If not, then you'll just have to ignore the warning.
I ended up letting around 10-14 PSI worth of air out of my Cup 2s, so I think it's a fairly common occurrence. This was Friday just gone, so not as hot as it is now, and I aim for hot pressures of about 31 PSI all round. I'd guess you'd want to be below 36 as that sounds too high.
I ended up letting around 10-14 PSI worth of air out of my Cup 2s, so I think it's a fairly common occurrence. This was Friday just gone, so not as hot as it is now, and I aim for hot pressures of about 31 PSI all round. I'd guess you'd want to be below 36 as that sounds too high.
Rojibo said:
If you push the stalk forward on the TPM menu, do you have the option to set race track pressures? (This might just be a GT4 thing). If not, then you'll just have to ignore the warning.
I ended up letting around 10-14 PSI worth of air out of my Cup 2s, so I think it's a fairly common occurrence. This was Friday just gone, so not as hot as it is now, and I aim for hot pressures of about 31 PSI all round. I'd guess you'd want to be below 36 as that sounds too high.
Circuit Mode for TPM is a GT car exclusive.I ended up letting around 10-14 PSI worth of air out of my Cup 2s, so I think it's a fairly common occurrence. This was Friday just gone, so not as hot as it is now, and I aim for hot pressures of about 31 PSI all round. I'd guess you'd want to be below 36 as that sounds too high.
Also aim for around 31PSI/2.1 bar all around when fully hot and after several bleed downs... once set - seems to stay around there all day. This is for 981 GT4 on Cup 2 N1
Also running ARBs @ Front-Medium, Rear-Hard.
Edited by TDT on Wednesday 2nd June 16:49
Going below 26psi triggers the low pressure warning on a 982 GT4 .. 31psi hot all round seems to work well .. by 34psi hot in the dry they are starting to slide which compounds the heat and pressure issue.
Contrarily, sliding in the wet helps to get heat into the tyre and the softer side-walled PS4S heats faster than the harder walled PSS … settling again on 31 psi warm ….
Contrarily, sliding in the wet helps to get heat into the tyre and the softer side-walled PS4S heats faster than the harder walled PSS … settling again on 31 psi warm ….
Come at the problem a different way, get your OPC to reinflate with nitrogen - they did this FOC for me.
You’ll find that the pressure do not increase anything like as much when they get hot so you probably won’t need to reduce them.
Before any one says, it’s not that there is anything special about nitrogen compared to air (which is of course 78% nitrogen anyway) but that nitrogen used for tyre inflation is completely dry whereas atmospheric air contains water vapour. It’s the water vapour expanding as it gets hot that is responsible for most of the pressure increase.
It’s a curiosity that although it’s now a Porsche standard for all tyres fitted by OPC to be nitrogen inflated, hence they all have the machine to do it, the tyres fitted at the factory are inflated with air!
You’ll find that the pressure do not increase anything like as much when they get hot so you probably won’t need to reduce them.
Before any one says, it’s not that there is anything special about nitrogen compared to air (which is of course 78% nitrogen anyway) but that nitrogen used for tyre inflation is completely dry whereas atmospheric air contains water vapour. It’s the water vapour expanding as it gets hot that is responsible for most of the pressure increase.
It’s a curiosity that although it’s now a Porsche standard for all tyres fitted by OPC to be nitrogen inflated, hence they all have the machine to do it, the tyres fitted at the factory are inflated with air!
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