77 replies to this topic

[Sputnik]

Cooper man, I was running at 32psi warm, taken about 5 min after the race, once we are out of the post race paddocks.

As the car was slipping sideways through the corners, I dropped the pressure to get more grip and after the last race they where all at 29psi warm.

In my inexperience mind, the harder they are, the less grip they will have, once you have past the point of maximum optimization of the tyres wrt heat and pressure.

I once and the back tyres at 34 and it felt extremely loose. Do you think that the optimal performance pressure for the D93's are at 40psi warm ? I have emailed plenty of web available email addresses to find out what the pressures must be, but not getting any response.

[Cooperman]

You do need around 40 psi warm for track use. I run 34 psi on rallying and sometimes a bit more for tarmac stages. When the tyres are too soft they do seem to slide a bit more.

[CMXCVIII]

Cooper man, I was running at 32psi warm, taken about 5 min after the race, once we are out of the post race paddocks.

As the car was slipping sideways through the corners, I dropped the pressure to get more grip and after the last race they where all at 29psi warm.

In my inexperience mind, the harder they are, the less grip they will have, once you have past the point of maximum optimization of the tyres wrt heat and pressure.

You do need around 40 psi warm for track use. I run 34 psi on rallying and sometimes a bit more for tarmac stages. When the tyres are too soft they do seem to slide a bit more.

For a rally man, Uncle Cooperman is quite good!

I've been involved with 5 GT Turbos and Clios on Michelin slicks and Astra and Civic Production Saloons. 40psi+ hot holds the sidewall rigid and keeps the tread on the track.

I'd also suggest the fronts want to be much fuller than the rears - maybe 8-10psi higher - but I confess I've never raced a Mini to know if that's the Mini norm too.

FWIW, single seaters run much lower pressures, but their weight, and particularly weight distribution and transfer, and their wheel geometries are very different.

[Cooperman]

Maybe we've now established the basis of the problem which is tyre pressures.
If it were me I would put about 44 psi in the fronts and 40 psi in the rears, stiffen the rear dampers a bit and go and do some timed laps. Then play about with damper settings taking accurate lap times after each re-setting, making sure you note the settings against the lap times. That way you'll know when things are improving, or not, as the case may be.
Try it with & without a rear ARB
Try to do it systematically so that you know what works for your driving style.

Edited by Cooperman, 15 October 2012 - 10:49 PM.

[Sputnik]

I actually found a person that is prepared to help me setup my car. He is located at the race track, about three garages from mine, and although he is not used to work on minis, he is eager to assist me.

The good thing is that the one condition he has, is that when he does a setup, t same day I need to take the car around the track to 'feel' the setup so that he can tweak it until am happy.

The price might be a problem, as he is a permanent employee of a local racing team, that races with Audi A4 3.0 Quattro super charged. The cars are imported from the USA as they run in production cars and we do not get supercharged Audi's in south Africa.

But let's see what happens.

[MIGLIACARS]

get saving pal

[ministar]

Personal reference goes a long way to finding what the best setup is for yourself. I've had under steer, oversteer and a neutral road holding car, and prefer the neutral approach with my evenly balanced mini.

I was able to hold much better corner speed compared to a lot of people at mini world castle coombe this year. Which for me is down to how well I know my car, and knowing what's going to happen next. And yes you get better with experience.

Most definately a mini must be driven with commitment and careful movements with the accelerator when cornering. A smoother driver is a faster driver.

[Sputnik]

Took my car this morning for the setup and got it back just after 4. Took it around the track a few times in two different sessions, and with warm tyres at 36 psi. Felt a bit hard, but got them to work nicely. Corner weights was also done, ride height a bit high, but will lower at a later stage.

The setup of the suspension is absolute weird to what the people on the forum suggested, but I must say, I never had such a sharp and control turn in and on the faster corners, once I am in the corner and feel the sideways skid, I just turn a bit more into the corner to induce body roll and the back tyre find some grip from somewhere that allows me to straighten the car up.

Must still work on my understeer I have on the exit of some of the corners.

Also interesting, is that when I was 'cruising' around the track my lap times was much better than when I was nailing it into the corners. This is as weird as the -2deg camber on the one back wheel and a stupid amount of toe out on the front.

Will see how it goes next week during the race.

[CMXCVIII]

Did you try different tyre pressures? 36 hot still seems low to me.

Surely understeer on the exit - after the apex - shouldn't be a problem; if you can get the power down, you want the car to drag you straight. Or do you mean it's still understeering too much through the corner?

[Sputnik]

CMXCVIII

i have not yet played with tyre pressures, but I will be doing so next week Tuesday after work. Do i start hard and go down or the other way round. ???

Turn in is better, but the understeer is after the apex i my mind, but can be throught the corner. The wheels does scream when it happens, and it is when I am int he rpocess to exit the corner. As mentioned, if I go light on the accelerator (50%) after the apex, the car drives nicely and handles well, but If I put pedal to the metal, that is when I exprence the understeer, until I start to straigthen the wheels. I then sometimes miss the exit apex by meters. Might it be that I am to "trigger happy" after the apex ???

[Sputnik]

Green line is the entering of the corner, Red the part I get understeer and the wheels are screaming. This is only approximates:

I get understeer on the last part of the red line, until the car is 90% straight again !!

Our Local Track



Turn 2



Turn 5

Edited by Sputnik, 23 October 2012 - 02:47 PM.

[jeffm5150]

Sputnik -- thanks very much for starting this thread. I have much of the same questions as you. Thanks everyone else for the great advice. This forum is such a wealth of information!

[Cooperman]

Don't even think of starting at less than 40 psi tyre pressures.
A powerful Mini will always understeer with power on. If it didn't it would be a very unstable platform indeed. You need to enter the corner with the back coming slightly 'loose' during and right after braking, then nail the throttle to the floor and balance the understeer with positive lock right through the rest of the corner. The sooner you are back on the power the better the lap time will be.
Try to find some photos of John Rhodes racing a MIni and see how he used the power-on understeer to win in his Cooper 'S'.
You really do need a lot of confidence to drive that way as if you subsequently lift off after going full-on in a corner you will almost inevitably spin.

[alsy]

John Rhodes......

[Cooperman]

That's exactly what I was trying to explain. John was always dramatic, but so very quick. In the video you can see the entry oversteer with the back going 'loose' then immediately checked with full power right through the corner. There was surely no-one who got back on the power sooner than John Rhodes. My old friend Mo Mendham used the same technique as well, but didn't get the same amount of tyre smoke as 'Smokin' John'.