street tyre pressure 4 trackday ?

[savvi]

wat would be the best tyre pressure for this trackday event im doing

http://www.southcanterburycarclub.org.n ... ircuit.htm

includes , tarmac auto x , 1/4mile , goo 2 whoa

e30 325 man, 320,000ks not rebuilt
195 50 16 roadstone kingstar, rims 7.5

should i top the oil up a bit more than normal for the hard cornering

someone must have done a few of these and if ya have any handy tips would be appreciated (if they work haha )

also getting my mechanic 2 put in new water pump, and new driveshaft bearing and holder 2 is there anything i should be aware of with these jobs like small clips or clamps that need replaced for the d/shaft bearing

[handpaper]

Assuming road tyres, set the pressures to manufacturer's spec, but with the tyres hot, not cold. Go out for ten minutes or so (less on a shorter track) to warm them up, then come in and check the pressure. If it's above standard, take it back down to spec. Go out again, come in and check. Repeat until the tyres are hot and the pressure doesn't go up any more.
If the track is cold or wet, drop the pressure by 20% before you first head out; this will help the tyres to warm up.

As for prep, make sure your oil is on the top mark of the dipstick and check it after every session. Prolonged running at high revs will make an M20 burn some oil, don't let it get anywhere near low. The E30 driveline is very strong; gearbox and diff problems are rare. The propshaft centre bearing does sometimes give trouble, but you're having that replaced.
I would replace/upgrade your engine and gearbox mounts; hard cornering and braking can easily break tired old ones. New OE mounts will be OK for one or two trackdays but I wouldn't trust them further than that - if you're going to do more, upgrade to bolt-through polyurethane or do THIS

[Simon13]

on my 15 inch BBS i drop them down to 26-7 PSI. They seem to go up 2 30-31 then on track and no tyre sqweel which is good

[UweM3]

I am the completeopposite than you guys. I run STREET tyres on track with MORE pressure. Street rubber is not meant to run at high temperatures as seen on tracks. So if you run them LOW they will experience far more movement in carcass and profile and heat up much quicker than desired, resulting in over heating. A road tyre will overheat on track sooner or later and by pumping them up 5psi above road pressure (COLD) you may get away with one or two laps more before over heating arrives. Tried and tested by myself

[caneswell]

A bit of extra pressure helps stiffen up the floppy road tyre sidewalls too. I run mine over 40psi hot.

[savvi]

I am the completeopposite than you guys. I run STREET tyres on track with MORE pressure. Street rubber is not meant to run at high temperatures as seen on tracks. So if you run them LOW they will experience far more movement in carcass and profile and heat up much quicker than desired, resulting in over heating. A road tyre will overheat on track sooner or later and by pumping them up 5psi above road pressure (COLD) you may get away with one or two laps more before over heating arrives. Tried and tested by myself

heers wat the the first event consists of 2.8ks 1.6ks short course , first autox starts halfway down the back straight, i do 2 loops of the short course then a run back down the main straight thru the ss then castrol curve and finish at the start of the back straight 3.6ks all up. course below

http://www.southcanterburycarclub.org.n ... ircuit.htm

[UweM3]

find a piece of road where you can do some "testing". Even a supermarket car park (EMPTY please) may be good for some tight turns. Take a foot pump and a tyre pressure gauge with you had have a trial and error session.
Start off with normal road pressure and change pressure 5 psi up and 5 psi down and see how you like it / how the car feels

[Black_Potato]

It all depends on the tyre, if the side walls are stiff enough you want to be dropping the pressure as the generated heat will bring it back up to ideal. If you have soft side walls you may need to add more to the tyre to resist tyre wall flex.

[AlpineAde]

I am the completeopposite than you guys. I run STREET tyres on track with MORE pressure. Street rubber is not meant to run at high temperatures as seen on tracks. So if you run them LOW they will experience far more movement in carcass and profile and heat up much quicker than desired, resulting in over heating. A road tyre will overheat on track sooner or later and by pumping them up 5psi above road pressure (COLD) you may get away with one or two laps more before over heating arrives. Tried and tested by myself

I use this approach myself.

Works for me.

[Simon13]

i might have to try this next time, i'd like to try R888's or something similar next time as i'm sick of road tyres going off

[Black_Potato]

i might have to try this next time, i'd like to try R888's or something similar next time as i'm sick of road tyres going off

Should have told me.. I could have brought you a part worn set for not very much ;)

Just FYI if and when you do... R888's 23-24psi cold to run at around 30psi hot.

[Simon13]

in 15inch Richard?

[bodger]

anyone clued up on this nitrogen gear they fill tyres with, would it not help reduce the pressure changing?

[Black_Potato]

in 15inch Richard?

Yep.. 195/55/15

I have a few half worn sets. As they only come with 5mm new tread, they wear quickly and they arnt great in the wet anyway. I would suggest runing the on a 2nd set of wheels and sticking them on when you arrive at track. That way you can run them until they are slick and wont get nicked or dead on the way home.

[Black_Potato]

anyone clued up on this nitrogen gear they fill tyres with, would it not help reduce the pressure changing?

In theory yes but you have to get all the moisture out of your tyres 1st so the benefit of your local garage adding nitrogen to a tyre with some moist air already in it is going to be of limited benefit.

So... if I had a mate who could do it for free I'd be tempted but I would go out of my way to get it done.

[miniblob]

Found this on another forum earlier (regarding nitrogen): Clicky

[sohlman]

Tyre pressures for track work is a bit of a dark art. I asked lots of people for advice and the following is now what i use.

I was told by Thorney Motorsport to bring a piece of chalk with you and make an x around the outside of the tyres where they cross at the point where the tread stops. Put in factory pressure and then go out and do a session. If you have worn past the crossing point inflate your tyres and remark. If you have not got anywhere near your crossing point deflate tyres. You will find that different tracks put different loads on the 4 corners. For example at Donington my right rear gets less heat in it and has a different pressure then the left front which takes a lot of abuse.

Also different tyres react in different ways. My toyo r888 are running at about 22 - 24psi hot where as the t1rs are running at around 32-36 psi hot. By the end of the second session i have 4 slightly different pressures in my tyres and they are too hot to touch. Also when letting out air be careful as the air can burn your hand. (ask me how i know!)

Wet weather i have not worked out, but i have been told lower them to get more heat by some whilst other have said raise them to make the tyre better at clearing water from the treads. My only wet track day i was useless so can't comment on this.

I have found that if they are too pumped up it feels like you are driving on marbles likewise too soft and you can feel the pain the tyres are going through.

Also bear in mind my only experiences on track are with my track prepared car and i am not worried about illegal tyres at the end of the day. More air will make them last longer, but in my opinion will give you less grip. Too low a pressure and the tyres can come off the rim.

i hope this helps

James

[Jon_Bmw]

That was a good read James. I think you'll find r888's come with serveral small triangles on the edge of the tyre, which will show wear if you are 'rolling' onto them(Same principle as marking with chalk, but better in the wet i guess). I am not sure if t1rs are the same or not... I have both in the garage, but its cold out there!

at the hand burning incident! Sorry.