unfortunately I have nothing inline this season in your area taking tire temps are good, but its sorta a hard task to do considering the temps are constantly dropping quickly.. plus theres really three main places on a tire and all have different temps.

 

We can catch up next time around in this area.

Thanks for your suggestions.

I think I have lots of different things to do to try and improve car rotation but wanted to get some ideas about tire pressures since that is the easiet to do while at the track.

 

Oh yeah, one other thing...Chalk helps too. Chalk the sidewalls to see where you're running--not only can you change pressures from front to rear, some people even do it from side to side....

 

Thanks all for more info on this. I will be running Monticello Motor Club and Lime Rock in a few days and will do a little tweeking there. I will try to post some results to let everyone know what was done.

 

awesome looking forward to your results! btw I forgot to mention.. you really want to be taking the "hot" tire pressure temperature as it will be different a lot of the time depending on the environement.

And you really want the tires to be at maximum grip and not really use it for increasing/decreasing oversteer. but if your suspension is limited you gotta do what ya gotta doo

 

Never tried higher front psi and lower rear psi. But had equal psi and could not get rear lose short of an abrupt release of the throttle. I like about 2 to 5 cold psi higher in rear better, but still low all around.(too low to post) DSC off always.

 

Justintime, I will check the hot temps after each run.

1985, those sudden releases on the track are not what I want to do as well. That is why I am interested in tire psi for some minor adjustability while I am at the track.

Will post some track results as soon as I have some.

 

I just got back from HPDE in Monticello Motor Club. Unfortunately it rained most of the day so I could not adjust the suspension tune. I did get one dry run in the morning and these are the readings:

Front Cold 35 psi Hot 44 psi
Rear Cold 38 psi Hot 44 psi

Understeer was still evident but this is OK. With a wet track, I did not want to over dial the oversteer.

I will have to wait for Lime Rock in a few days to get more information.

 

OK, something to report from LRP. I can get both TTO and TBO quite easily with the following setup.

Front cold: 33 psi Hot: 41 psi
Rear cold 40 psi Hot: 46 psi

Lots of controllable rotation.

PS: Tires are Dunlop Direzza Z1 Star Spec 215 45 17

 

Thanks for the info! I will give a try to similar pressures on my next track day. I have the same tires.

By the way, what do TTO and TBO stand for?

 

TTO - Trailing Throttle Oversteer
TBO - Trailing Brake Oversteer

 

Thanks again! I see these are some advanced techniques which I have yet to learn!

 

Great way to get an exaggerated idea of how these things work is to try it in a snowy or icy parking lot (A BIG lot, where there is nothing to hit).

There is a certain amount of finesse involved with doing it well; I'm still learning the art myself--these things can really bite you in the butt literally and put you into a nasty spin.

TTO is a bunch of fun, and you can play with it on carousel's and sweepers relatively safely provided you're not too abrupt and do it smoothly; you can feel the car and hear the tires begin to give well before they will.

TBO is more difficult, at least for me--more is involved with timing--getting the initial brake point just right, downshifting, and trail braking. It's beautiful when it all works just right, but I'm not consistent with it enough yet, so I will only work on it on places on the track that are relatively slower and safer.

If you can, sit in a car with someone who can do these with ease; it's really cool how some drivers can get a car to rotate quickly and under control, something to aspire to.

 

Uzun,

Please be really careful when attempting TTO and TBO especially when you have a very aggressive rear sway bar. Oversteer means you are sliding the back out.

Have fun and post some results to see if this worked.

 

Will do!

I intend to practice these techniques in a safe environment first, such as a big empty parking lot before I try to apply them on a track.

 

I forgot to mention that many bmwcca car clubs especially here in the north east run many car control clinics where you can learn and practice car control (including TBO and TTO) in a safe environment. Maybe they have the same programs down in FL.

 

Thanks! I will definitely check to see if they run those events somewhere close to me.

 

Somethings to be aware of:

1. TURN OFF DSC before each Track Session. DSC is designed to predict when (under normal driving conditions) to kick in to save the inattentive driver's butt.
   However, on the track, the corrective programing is way too conservative. The car will bog down and go into understeer mode. When driving on the track, the computer thinks;
   "This stupid S.O.B. is about to go out of control! I can sense that he just put the car into an over-steer situation or is driving out of control and since the average human would go into a tail spin, I'd better tweak the brakes and or cut back the throttle so that at worst, he goes into an under-steer situation that maybe he can handle."
2. As stated before, YOU NEED A PYROMETER http://www.longacreracing.com/catalo...id=200&catid=7 and a tire gauge http://www.longacreracing.com/catalo...id=222&catid=8 The ONLY WAY and (ITS EASY!) to properly set tire presure is with a pyrometer.
   Here is great article about setting tire pressure, IT WORKS! http://www.turnfast.com/tech_handling/handling_pressure Once you figure out the best tire presures to use, you don't have to get the pyrometer out each time. The nice thing about a racing type tire gauge is that you have a bleeder valve button that you push to let air out. Just start out with at a higher air pressure than desired and then bleed off air pressure until you get your desired air pressure. REMEBER, as stated in the turnfast article, you must take the temp settings while hot-pitting. Its' too late after your cool down lap.

 

Thanks for the info. I have read and tried to implement this many times. The info on page 5 is what we are trying to do. But to get TBO and TTO in a FWD, it requires the psi to be even higher in the rear.

I understand turning off the DSC. I talked with many skippy instructors about this and they have differring opinions about it in a DE (not racing). I used to take it off but lately I have been leaving it on because as you become more smooth in the inputs and turns, it does not seem to intrude while still giving you an element of safety coverage.

Also for drivers who are not soloing yet, leave it on.

 

You can still get TBO and TTO with the rears lower than the fronts--I've actually switched to this per one of the guys at TSW's recommendation, and I've found inducing TBO/TTO is much more predictable. I'm definitely faster with this setup, my theory is I'm rotating quickly with less sliding (which kills speeds), who knows for sure....

I can't run with DSC on, but I do have a limited slip. Leaving DSC on is borderline dangerous if there is a car close behind you on the track; it really can cut power down when accelerating out of a corner.

There are other systems (ie Porsche) where the stability control is much less intrusive, and it's fine to leave on--heck, even the 2nd generation MINI's DSC is quite a bit less intrusive; personally I think the first gen DSC, while great for everyday driving, is horrible for the track.

And if you're messing with TBO on the track, the DSC is not going to like that one bit when you hammer the pedal back down...

 

How low do you have your rear psi to induce TTO, TBO?

I start at cold 33 psi on the front, lets say 9 psi more for hot, giving a hot psi of 42 psi (tire temp consistent around 190-195 F). Let us start with cold psi of 32 psi rear, with 6 psi more hot, I get 38 psi. Is this about right? I just want to get some idea of what the ball park is to try it, having tried the other school of thought.

I have a r56 so I cannot comment on the r53 DSC. You are very likely correct about it. But this is a personal thing about the DSC. With my driving, I don't think it makes that much of a difference on the tracks that I visit such as LRP. Perhaps your driving style changes with it on versus off?? With it on, it forces me to be more smooth. And I could be losing 1/10s with it on but with DEs there is no prize for coming in first. I am just trying to learn to drive well with what I have. Just being safe and having some fun.

Having not enough acceleration out of turns is not that dangerous, just do a point bye and stay on line. That is where that R8 and modded Corvette (with r-comps) always seem to get me .

 

I'm riding on R-comps, so the pressures are a bit lower (I'm assuming you're running a high performance summer tire at those pressures).

So if it's really hot out, I may start out as low as 23 on the rear, 25 on the fronts. The cooler, the higher I'll start the pressures out, and I aim for 33 front/35 rear hot, that really seems to be the sweet spot for the Nitto's. I'll chalk my tires, and use that to fiddle with pressures once I've hit 33/35. What I really need is a good pyrometer....I'm still playing around a bit with the pressures, but the quickest I've ever run at Blackhawk was on those settings.

With the DSC on, it forces me to be slow. Only way I can describe it. I personally think DSC hinders learning, because it kicks in and covers your mistakes to a certain degree, but it interferes too even when you do something spot on. I've left it on accidentally before; you notice it as soon as you hit your first major turn, it's dramatic, and my reminder to turn the damned thing off.

It's ok to make mistakes on the track, it's how you learn--you just don't want to be making major mistakes at high speeds; high speeds/slow hands generally will keep that from happening. You don't want to go into a high speed spin or anything like that (been there, done that, can live without it), but the DSC will force you take corners much slower than optimal, and even when you hit it right, it'll kick in depending on the corner. So as a safety aid, yeah, I guess it does that to a certain extent, but it's not going to teach you how to drive on the track any quicker--it'll hinder progress.

Having acceleration cut out, out of a turn, can be very dangerous, depending on what level you're driving at and how close they're following you--it's amazing how quickly things can happen on the track. Plus, the whole key to driving fast on the track is getting the exit speed just right--come in to a tight turn on to a very long straight, you're exit speed is critical to a decent lap--DSC cuts in, and you're hosed. It's one of the most important factors in driving the MINI fast--we can get through the corners carrying more speed, and that exit speed helps compensate for our relatively lower HP. With the DSC on, I'm losing way more than tenths--rememember each MPH slower you come out of an exit carries over the length of that next long straight you're entering; you come out of a corner too slow, we are living with that mistake that whole long straight--we simply don't have the HP/Torque to compensate, like the high end cars do. It's one of the beauties of the MINI--to drive fast, you have to drive well; you can't be totally off line then hammer the gas on the straights and catch up like you can with other cars with insane HP (what fun is that anyway?).

Personally I think a better way to learn is to drive slower with the DSC off, then gradually increase speed as you get more seat time and experience. At some point, you're going to want to flick off the DSC, and it's going to be like starting over.

 

I understand your point, no issues. Hope you understand mine. Yes, I am running street tires so they are different.

I guess we will disagree about DSC which is OK. I just work with what I think is best for me. In my group, I can run with many highly modded Minis with r-comps with my little mod setup, street tires and DSC on. There is little abruptness or slowing down in corners due to the DSC as far as I can tell. Be smooth and that really helps with the exit speeds. No DSC when you really need it, you are really hosed. Just be safe.

 

I respect everyone's opinions on DSC. Back in April, I had an experienced racer (he is Ian Stewart, you may already know him, he is a member on here and he has set lap records in time trials in his R53 at various tracks) drive my R56 at Sebring with DSC on. This guy knew what he was doing but the DSC was still kicking in way too much. After seeing that, I decided to turn DSC off whenever I drive on a track. Although I have only done 6 track days so far, I feel like DSC off is a must for good lap times on the tracks I go to. I have not spun the car or hit any walls yet with DSC off!

 

You do what you are comfortable with. That is the most important thing.