HPDE - Inflation Pressure ZCP

[gsrbri]

Anyone running a ZCP at HPDE events give some advice regarding inflation pressures? I realize it's a bit temperature specific, but I'm planning to run around 38 psi all around (+3psi over stock) and see how it is.

First time to a DE event w/a 19" wheel car and this set-up.

Thanks!
-Brian

[Erhan]

Start with stock or +3, and check the temps & wear after your first session. Use chalk if possible. Also see this: http://www.m3post.com/forums/showthr...2#post10428472

[elh0102]

Originally Posted by gsrbri

Anyone running a ZCP at HPDE events give some advice regarding inflation pressures? I realize it's a bit temperature specific, but I'm planning to run around 38 psi all around (+3psi over stock) and see how it is.

First time to a DE event w/a 19" wheel car and this set-up.

Thanks!
-Brian

At 38 all around you'll be close enough that other things should then be your focus. Of course, 38 should be your target at temperature, so you'll need to start lower, say 33 or 34, then check them as soon as you get off track.

[gthal]

38 to 40 HOT works well IMO which means somewhere between 32 to 34 cold. If you intend to run 38 cold (which likely means mid 40s hot) the car will not grip well, will feel very nervous and you will completely wear out the centre of the tire.

[e90_2_f80]

Originally Posted by gsrbri

Anyone running a ZCP at HPDE events give some advice regarding inflation pressures? I realize it's a bit temperature specific, but I'm planning to run around 38 psi all around (+3psi over stock) and see how it is.

First time to a DE event w/a 19" wheel car and this set-up.

Thanks!
-Brian

I ran 30 front / 32 back at VIR in august. After 30 min I was at 38F, ~39 back. On ZCP with contis.

[MaxL]

I believe the OP means stock suspension/camber and stock tires. And it's his first time, so he's going to start relatively slow with not much extra heat in tires. If that's the case, it's better to start at 38 cold and then check pressures every other session or so to keep them slightly above 40 hot. Why so high - stock tires have soft sidewalls that roll easily with stock camber, especially if steering input is not smooth, which is typical for first timers.

You will not notice a tiny bit lower traction, but you will appreciate saving more of your tires and having somewhat sharper steering feel.

[Merked M3]

Originally Posted by MaxL

I believe the OP means stock suspension/camber and stock tires. And it's his first time, so he's going to start relatively slow with not much extra heat in tires. If that's the case, it's better to start at 38 cold and then check pressures every other session or so to keep them slightly above 40 hot. Why so high - stock tires have soft sidewalls that roll easily with stock camber, especially if steering input is not smooth, which is typical for first timers.

You will not notice a tiny bit lower traction, but you will appreciate saving more of your tires and having somewhat sharper steering feel.

I think that even a novice will heat up the tires significantly. Something like 34 front, 33 back sounds about right. Chalk it so you make sure the right amount of tread is used and then check after the sessions.

[gsrbri]

Thanks for the inputs, guys.

It was a cold morning up in NH (49 degrees and warmed to around 60 degs), so a bit tricky w/inflation.

I started out at 38 cold all around and seemed to do okay. However, hot temps got up over 42 psi, so I lowered to around 40 psi hot. Got a little more grip and tire wear seemed reasonable for a one day event.

I'll continue to experiment, but the day was a lot of fun and the car is great.

-Brian

[turbo8765]

Originally Posted by bmaktabi

I ran 30 front / 32 back at VIR in august. After 30 min I was at 38F, ~39 back. On ZCP with contis.

How did the contis do? Did they get greasy after a few laps?

I haven't been impressed with them on the street.

[Bubbles]

Originally Posted by turbo8765

How did the contis do? Did they get greasy after a few laps?

I haven't been impressed with them on the street.

I ran Conti 3s at the Nurburgring and the tires performed fantastic.

[turbo8765]

Originally Posted by Bubbles

I ran Conti 3s at the Nurburgring and the tires performed fantastic.

Thanks for the response, but its tough to gauge. Like most of us I've never run the Nurburgring. It's such an unusual and fast track that it's hard to compare. How many laps? What were your lap times?

Have you ran a different tire on the same track that you could compare the contis to?

I figured, with the power and weight of the e92, that the contis would start to get loose after a few laps. Also, the outright grip on the street is very underwhelming. This is consistent with the relatively high tread wear rating.

[llis]

Originally Posted by turbo8765

How did the contis do? Did they get greasy after a few laps?

I haven't been impressed with them on the street.

I hated the Contis. Greasy after 3-4 laps at HPR. They now sit in the back of the garage, waiting for the day I part with the car. Blah!

I went to AD08s and it was a different universe.

Re tire pressures, I dont have notes from the Conti weekends. On the Yokohamas after much experimentation I found it best to start at 28-29 and aim for 36-37 hot. YMMV.

[turbo8765]

Originally Posted by llis

I hated the Contis. Greasy after 3-4 laps at HPR. They now sit in the back of the garage, waiting for the day I part with the car. Blah!

Figured