atxe30 Posted August 27, 2021 Report Share Posted August 27, 2021 (edited) Any of you e30 guys have knowledge you'd be willing to share on tire pressures? Ran today in hot weather with starting at 31F/30R. Hot temps 36 front and rear. Edited August 28, 2021 by atxe30 Quote Link to comment Share on other sites More sharing options...
enginerd Posted August 27, 2021 Report Share Posted August 27, 2021 (edited) 5 minutes ago, atxe30 said: Any of you e30 guys have knowledge you'd be willing to share on tire pressures? Ran today in hot weather with starting at 31R/30R. Hot temps 36 front and rear. Tire width and vehicle weight will affect things. Your car is certainly heavier than mine so you will want slightly higher pressure all else being equal. I have had success between 30-35 for hot pressure but on different tires (re71 / a052 / rs4). I also won't claim to have optimized our pressure with any kind of rigorous testing but it's a good ballpark. I would take 3lbs out for next time and see what happens. Edited August 27, 2021 by enginerd Quote Link to comment Share on other sites More sharing options...
atxe30 Posted August 27, 2021 Author Report Share Posted August 27, 2021 (edited) 3 minutes ago, enginerd said: Tire width and vehicle weight will affect things. Your car is certainly heavier than mine so you will want slightly higher pressure all else being equal. I have had success between 30-35 for hot pressure but on different tires (re71 / a052 / rs4). I also won't claim to have optimized our pressure with any kind of rigorous testing but it's a good ballpark. I would take 3lbs out for next time and see what happens. ya, sorry, 10 inch wheels, cars at 2300. Edited August 27, 2021 by atxe30 Quote Link to comment Share on other sites More sharing options...
enginerd Posted August 27, 2021 Report Share Posted August 27, 2021 27 minutes ago, atxe30 said: ya, sorry, 10 inch wheels, cars at 2300. Pretty close to us and the other e30s. If you have the time to experiment I would start at 29 cold which will probably come up to around 35 hot and work down from there. I expect you to find good grip and wear somewhere between 35 and 30. 1 Quote Link to comment Share on other sites More sharing options...
MichaelPal Posted August 27, 2021 Report Share Posted August 27, 2021 Ditto ^ we usually start at 29cold and I’ll adjust based on track + tire temp distribution. Do you have have a pyrometer? While pressure is a good tool, adjusting it in concert with temps is ideal. Quote Link to comment Share on other sites More sharing options...
Indysupra Posted August 27, 2021 Report Share Posted August 27, 2021 Your camber will also affect how much pressure is “optimal”. 2 Quote Link to comment Share on other sites More sharing options...
atxe30 Posted August 28, 2021 Author Report Share Posted August 28, 2021 17 hours ago, atxe30 said: ya, sorry, 10 inch wheels, cars at 2300. thanks to all for input. think i started out pretty close so now time to experiment a bit. @MichaelPal ya, have a pyrometer, will def be used 2 Quote Link to comment Share on other sites More sharing options...
Jamie Posted March 7, 2022 Report Share Posted March 7, 2022 Not sure how i found this thread but I am going to bring it back from the dead. I like to play in the 28-32psi region. I think this is mostly because I like the number 30 and very little science. But i take pyrometer reading in practice and they seem okay.I just look that it's coldest on the outside and hottest on the inside. I have some setup book that guides you through pyrometer readings but it feels like reading tea leaves when you actually do it. Would love for someone to tell me I am over simplifying this though and school me. I def don't start with tire pressures at 29psi cold. I start at 25psi max. The 6 psi raise that @enginerd stated he saw is on the lower side of what I observe. I do have notes from the rival 1.5s that back this up but I only run those in mix conditions in the winter (note: Im west cost) so it seems like trash data. I find faster more aggressive drivers will see a ~10psi raise from cold. I also try to keep the tires always under 35psi (hence the 25max rule of thumb) and tend to trend on the lower side of the tire pressure game at the track. I use tire pressure to try to correct over and understeer. But it doesn't seem to be the most affective tool. its just something to twiddle with during a race to make you feel like you did something. I am sharing this not because I think its the right way but because I would love to hear a different approach. 1 Quote Link to comment Share on other sites More sharing options...
mender Posted March 8, 2022 Report Share Posted March 8, 2022 (edited) I try to do a test and tune devoted to tire temps and pressures. The cold psi is just a starting point for future reference and I don't use tire pressures to change the handling during that session. Typical day: set and record tire pressures, go out and warm up the car, the tires, and myself, usually 5-10 laps with the final laps pushing hard ("qualifying" pace). Come in, take tire temps right away, then tire pressures right after. Make camber (check toe after) and pressure adjustments that seem necessary according to the temps. Do another session of warm up and Q pace. Repeat as needed until I'm happy or I can't adjust more. Usually three sessions before noon. Make any major suspension changes at noon that might be indicated for balance, etc., then back out for more testing. If the car is going to be in the sun, make a note of the pressure difference in the sunny vs shaded tires. By the afternoon, the tire temps should be within range and toe changes can be played with to tweak balance and turn-in, then finally bumping tire pressures to see how they influence balance. Notes for the day include track and weather conditions. Pack up the car, head home, check the tire pressures that evening and again the next morning, recording ambient conditions again. If one tire is noticably lower in pressure after sitting for a day, fix it before the next session or race. You should now have a pretty good idea of what your cold psi should be set to for the expected mid-afternoon weather conditions. I don't usually play with pressures during the race, so the last driver usually has the best car, hopefully making up for the wear during the day. Does that help or were you looking for something else? Specific questions? Edited March 8, 2022 by mender 2 Quote Link to comment Share on other sites More sharing options...
mender Posted March 8, 2022 Report Share Posted March 8, 2022 (edited) Here's an interesting video that shows live tire temps during a lap: Edit: it's an S2000! Edited March 9, 2022 by mender Quote Link to comment Share on other sites More sharing options...
ross2004 Posted March 8, 2022 Report Share Posted March 8, 2022 2 hours ago, mender said: It's a FWD (Civic) It's an S2000 Quote Link to comment Share on other sites More sharing options...
mender Posted March 9, 2022 Report Share Posted March 9, 2022 4 hours ago, ross2004 said: It's an S2000 Oops, I saw the Honda emblem and assumed! Quote Link to comment Share on other sites More sharing options...
Jamie Posted March 9, 2022 Report Share Posted March 9, 2022 (edited) So let's talk about that videos data. First off it Looks like there is something wrong with the LR sensor in that video or maybe the tire, maybe the exhaust is near it? I watched it a couple times. Here is my not experienced thoughts. Left side gets significantly hotter (makes sense on the CW track). It seems that the outside is getting hotter than the inside so I would suggest trying more camber. Say i didn't have time to change camber (who really does this at the track?!) and I can only do tire pressure. I am not sure this data would help me make any changes. Maybe lower higher pressure to reduce tire roll? Edited March 9, 2022 by Jamie Quote Link to comment Share on other sites More sharing options...
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