I just finished my 6th autocross today in the street tire class running my MCS in NGS. I am running on Kumho 215/45/17 MX tires. I am having problems with wheel spin accerating out of corners when I have to downshift to first gear. I am running 43-46 in the fronts and about 4 pound less in the rears. I am thinking of trying decreasing pressure for next week's divisional race. Anybody have any ideas? :???: :???: :???:

 

install an lsd, that will fix it up just perfect. of course then you probably wont be in the class you want....

 

I had my first autocross yesterday in the MCS, same tires as you. I started out at 36f/36r. Worked pretty well, but I had wheel spin also. I ended up adding 2 pounds to the front because they were washing out in some of the corners. I think the added pressure probably made the wheelspin worse. Makes sense, drag racers use very little air pressure.
I think I will work on drving technique to help with the problem: hitting the brakes harder to get the rear to rotate out a little faster. I hope this might get me straight sooner and help the problem.
Tell my about your tire pressures: have you experimented very much with them? Have you tried a pyrometer?

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IB/W 17" OZ Superleggera's Kumho MX tires
Aero Grills
<IMG SRC=https://www.northamericanmotoring.com/albums/album04/egc.thumb.jpg>

 

For running in G Stock (Cooper S) and H Stock (Cooper) there isn't a great deal you can do resolve this problem. The best recommendation that can be made is to work on being very smooth on power application when coming out of turns. The good thing to remember is that almost everyone in these classes are facing the same issue. Smoothness will make the difference.

If you plan to move to a class like STX, SM, or a street prepared class then a LSD is a must. I had the chance to take about a dozen runs in the TEAM MCO STX car last Friday and was very pleased with the way the car performs now that the LSD is in.

Mark

 

Technique is the answer. The sooner you can get the car to rotate, the sooner the car will level out and you can apply power. I drive a MCS in GS and have learned to rotate and to be as smooth as possible on the gas. I run 46 lbs in the front and anywhere from 36 to 42 lbs in the rear depending on the surface. I should tell you that I am running Kumho Victoracers 225/50/16. The higher rear air pressure helps the car rotate. Also helps you spin repeatedly if you are not careful Abe(still learning, but having a lot of fun doing so)

 

Thanks Junkman, what wheels are you using to be able to run 225/16/50 tires. How is the clearance? :???:

 

In the rear, the tire has rubbed the paint off the trailing arms towards the front of the wheel well. At the rear of the wheel well, the tire rubs on the inner wheel well at about the 2 o'clock position. I do have a small hole worn there, but that is after many runs. I think it only rubs when I drop below 35 psi in the rear tires. I run 40 ussually to start and adjust as necessary. I have the SSP wheels from AK. They are 16X6.5(stock class). When I get Hoosiers, I will get 215/45/16. Kumho does not make that size. Abe

 

In my H Stock Cooper, Koni rears set firm, SS+ suspension, I run 205 Hoosiers on the R-84's with as much toe out rear as possible.

That being the baseline, I don't have problems much spinning out of slower turns, now that it's midseason and I'm learning the car, unless I'm overdriving the throttle.

I run the fronts usually at 45 psi and the rears at 35.

Frankly I'd rather have a little understeer problem out of corners than spinning the tires out of corners since it's all about speed maintenance in the underpowered Cooper, and I can correct better for Understeer than I can for lack of LSD.

When I start to push out of a corner or fast sweepers I just oscillate the steering wheel rapidly back and forth INTO the push direction and wait for the Hoosiers to catch back up. Works pretty good for me and keeps me on the edge of the slip angle.

Roatation is nice, but in H stock and G Stock in a lot of turns to be competitive in the PAX you gotta keep the speed up through the corners, and IMHO you are gonna be on the edge of a push a lot of times since in Stock you are suspension limited to get that rotation mechanically.

The only two other things I haven't tried seriously yet is unhooking the front sway, and 'overinflating' the rear tires.

So far doing well in locals, still leading the points race. Finally got another Mini Cooper to show up from the local Mini Club! Great to see other Mini's at the ax! Unfortunately he has the kind of job that requires vacation to get time off to race on Sunday.

UtahAugs

 

One last suggestion... are you sure that you need to be shifting into 1st gear?

This is the biggest "rookie" mistake made in autocross.

1st gear should be only used when you launch the car and trying to come out of VERY SLOW 180 DEGREE turns.

Other than that 2nd gear is your friend. I've heard 1000 times from someone new to autocross "but it makes more power at higher RPM in 1st!" Well while this IS true you will be slower due to wheelspin issues and ithe inability to be "smooth" with the car in 1st gear.

Mason

 

I tried to use second on a longer course. It didn't work well. The mini really dogs coming out of the corners in second. The mini will do 50mph in first so I use first for most situations.

 

IMHO the biggest rookie mistake in autocross is going too fast and not squezzing on the throttle (regardless of gear).

Agree that a lot of corners can be taken in second, but it may be faster in a number of them in addition to pivot cones and 180's that can be taken with a downshift to first as long as one squezzes the power on coming out. You may be able to come out quicker without tire spin rather than ******* out in second.

There's just too many variables to give a general answer other than 'it depends."

My2centsAugs

 

Keep in mind shifting cost you minimum of .3 seconds per shift.... MCS or Cooper should only use 1st for very slow turns and the start... the car may feel better in first... but it will be faster in second. Annother thing I do not really belive in is over inflating rear tires to induce over-steer... by over inflating the rears they do not come up to temp giving the desired over-steer... but you are not getting near the full potential of the tires... by playing with pressure in the rear you should be able to get the desired over-steer keeping in the tires working pressure range ... by using the slip angle of your tires.... putting some (ok as much as you can get) toe out in the back is key for this to work... (I leave my car this way for the street with no noticable negatives...inc tire wear) FYI I run Kuhmo V700 205/45/16s 45 front and 40 rear is my starting point....

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Jason

03 MC Black/White
#13 H-Stock.. Atlanta Region SCCA

 

I agree with you mostly ccone, but .3 seconds a shift? Sure, if done improperly and at the wrong time. That being said I agree generally one should short shift to second and keep it there, but if you can heel and toe, then you won't be loosing .3 seconds in those corners where heel and toe is appropriate.

I actually heel and toe with my heel on the brake and my toe on the upper part of the throttle, almost the pedal shaft.

Size9Augs

 

Ok, well you can believe what we have to say or not that's the beauty of being individuals. But this isn't something I've thought up on my own, I was once a believer in the 1st gear theory...

Then came along a few National Champions for some rides... First thing they ALL said was shift to second and leave it there! I heard this from someone who's a 2 time National Champion in an Acura Type R (with less torque than a MCS). This National Champion told me he never downshifts unless it's a painfully slow 180 degree turn.

So believe what you want, but I'd suggest trying a few runs with and without the downshift and see what the stopwatch tells you.

Mason

 

I too just started autoxing and,like you had a hard time not spinning out of any turn..In my first race i stuck it in second it was spinning so much.that was my fasted pass of the day.the harder i tryed the slower i went.so now i just try and drive smooth..roll on the gas and hard on the brake. allso as i read somewhere ..in a turn
if it starts to push start turning the wheel back and forth,works for me!
i'd love to hear more driving tips so post um!

 

The MINI is an extremely well balanced FWD car. The problem most people have when they first start autocrossing is they really want to "overdrive" the car. For whatever reason(myself included) when I started autocrossing I thought people would be impressed by how well I could "overdirve" the car. The reality of overdriving is that it's the slow way around the course. The easier you make it look the faster you normally are. Granted, don't go out there and act like your driving Miss Daisy. Drive agressive, find the limit, but once you find it don't act like you can drive past it. Everycar has it's limits, the MINI's are very high but they still exist. Learn them and you'll be very happy(and fast)...... Have fun with your MINI.

Stuart
HS47