Ok, so, I autocross my 2008 Mini Cooper S with a JCW Tuning kit. I have the JCW suspension and factory LSD. I have an H-Sport rear swaybar as well as Koni Double Adjustable shocks/Struts.

With the setup, as well as others with the same setup, the rear wheel often lifts off the ground while going around a sweeper, which, is fine. The issue is, when the inside rear wheel is in the air and I attempt to accelerate out of a sweeper, if I have ANY wheel spin at all, throttle is cut down to about 30%. Throttle stays at 30% until I fully lift off the throttle, then, it goes back to 100% immediately. On a few runs, I had 30% throttle for 30+ seconds!

This has been going on all season long, and, I am about to just throw in the towel and sell the Mini if I cannot figure it out very soon. I have been to my dealership 3 times and they cannot figure out why this is happening. The worst part is, I obviously cannot duplicate this on the street, so, its impossible to show the dealership first hand of the issue. However, they know I autocross and believe there is an issue, we just cannot figure it out.

Does anyone have any idea or has anyone else experienced this same issue? I'm wondering if the programming thinks the Mini is getting ready to tip over or is on ice so it shuts things down.

I'm about to just start shooting in the dark and swapping parts out. I know there is a lateral G sensor or Yaw sensor present in the car, maybe mine is over sensitive or something.... Maybe a throttle position sensor? Or, maybe a faulty wheel speed sensor? They have pulled codes on every visit but nothing ever shows up, so, I don't think it is a wheel speed sensor.

Any ideas are greatly appreciated...

 

With DSC off you shouldn't be getting any intervention at all. I don't autocross, but on the track I don't get anything like that. I can spin the inside wheel (and still get power thanks to the LSD).

DSC really is off?

 

Yes, DSC is definitely off.

One other thing I forgot to note, I have been autocrossing Mini's since 2004, and, have owned 5 different Mini's including 3 R56 Mini's that have been prepped for autocross. This is the first Mini that has ever done this. However, this is the first Mini to ever have the large rear bar though as well since 2012 is the first year that stock class allows an aftermarket rear bar. Last year, the throttle cut off happened maybe every 20th run or so with the JCW 18.5mm rear bar. This year, on Hoosiers with the Solid Race bar, it happened maybe 1 out of 10 runs, now with the BF Goodrich R1-S tires(more grip than Hoosier), it happens probably 4 out of 5 runs.

 

Just another data point for you... Mine is a 2007 Cooper S with LSD and also with the JCW tuning kit, JCW suspension, DA Konis, and a big rear bar. I am driving RTF on street tires this year. Mine has never exhibitted the throttle cut behavior that you describe as far as I know.

EDIT - Also mine has the DSC, which I understand was optional for 2007s, and I always run with it tuned off. Except when I forget....

 

One more thought... Do you run with the Sport button ON? And if so, have you tried turning it off to see if that makes a difference with this problem?

I always run with the Sport button OFF because I like the throttle to be linear.

 

This is not going to help much, but maybe you can use it to better pinpoint the problem.

Perhaps activating the ABS re-arms the DSC temporarily. My RX-8 would feel like it distributed brake force to keep me from rotating if I activated the ABS on hard trail brake, even though I deactivated the DSC. Eventually I found out that a long press of the DSC button faults out the system making sure it's permanently off until the next key cycle.

 

on my 2012 CMS All4, if i turn off DSC, i get DTC (or Traction Mode), pressing and holding the DSC button a second time (i think for about b3-5 seconds) turns off DTC and you are "on your own", no intervention from the computer ... ABS is still active

scott

 

Dear Craig - you are my hero because I just saw your car (and you perhaps) as a passing glimpse on the Mobil 1 "The Grid" show that just aired on SPEED featuring the Spring Nationals. Wow, Solo II on the big screen! What an unexpected pleasure.

Cheers,

Charlie

 

Yup that was him in front of the car. Saw the same clip.
He's taller in person ;-)
Running in the KC Region has it's perks.

 

Any updates on this issue Craig? Still happening?

I haven't had this problem (yet) - it makes we worried to try a thicker rear sway...
My car does not have the mechanical LSD - only the EDLC. It has taken me the better part of last and this autox season to get used to the throttle on this car - tight turns and your foot to the floor does not prove to be effective for times sake - the ECU and/or brakes simply cut throttle - ive really had to learn how to modulate the throttle and feed it in as I straighten the front wheels.
I realize this is a different setup than what you have; just thought I'd share my experience in learning to drive the JCW in the autox environment.

 

I haven't had the opportunity to see this yet, although, I was told by a local autocrosser that I have a face for radio rather than TV. I'm definitely excited that our sport has made it on TV, maybe more to come in the future hopefully?

 

I am having a new issue in addition to the throttle cut off.....

With WOT, I am having some pretty good pinging noise going on in the engine. Thanks to TazMinianDevil, he pulled the code and verified it to be a "super knock" code. I am taking the Mini in Thursday for a scheduled service where they are going to verify the code and he said they would clean the valves and possibly the injectors from carbon buildup(I think that is what he said). So, hopefully the pinging issue will be resolved.

In regards to the throttle cut off, I believe that it is rear swaybar with wheelspin related. With the rear tire off the ground and a bit of wheelspin, throttle is cut off because the DSC/ECU/SENSOR or something thinks the Mini is tipping over so it cuts down throttle. I have learned to drive around this with a quick throttle lift then back on throttle. I think the issue is more prevalent now that we are on BF Goodrich Tires. The grip is a bit better than the Hoosiers which is causing the Mini to load up a bit more compared to other tire manufactures. With that said, I'm "sticking" with BFG and will find another solution, that tire is amazing!!!

The solution is to get the inside rear tire back on the ground, there are 2 ways to do this(actually 3, add compression up front, but, I am already maxed out, need to re-valve the fronts I guess), run softer rebound on the rear shock and run a softer bar. Running softer in the rear will cause understeer, so, other compensation will be needed to allow for good rotation in sweepers. That will be done by going to a road race rear tire, in my case, the BFG R1. Solutions and setup that I have tested and are getting ready to test are.....

1) 25mm Hotchkis Solid Race Bar - rear rebound on Koni set at 1.5 turns off full soft. throttle cut down to 30% at every single event on most runs - this bar is too stiff, even on the softest setting for MY mini. The rear tire is about 8 inches or so off the ground for extended periods of time, then, with a bit of wheelspin, it thinks the Mini is tipping over and cuts throttle. The rear tire even lifted off during slaloms, which, was not optimal and unsettled the Mini.


2) 25mm Hotchkis hollow bar - rear rebound lowered to 0.5 turn off full soft - throttle cut off is still there on most runs but not on as many sweepers, might happen 1-2 times per run. I put the bar on full soft as well. I also went to a BFG R1 road race tire for the rear to compensate for the bar not being as stiff. Handling works quite well in a 235/40/17 R1-S up front and a 235/40/17 R1 in the rear. I actually liked the feel of this setup better than the race bar with the R1-S tires in the rear. However, More is still needed to be done to get this to work. Solutions for this bar would be to machine an extender to allow for a softer 4th hole to be used on the bar. I will have to take the bar to a machine shop to see if this is possible. Or, go to a softer bar. - One additional solution to resolving the throttle cut off is to take rebound out of the front to eliminate all wheelspin - I did this and verified that this is a 100% fix if rebound is set low enough, but, the Mini then drives like a boat through slaloms, which is not a good thing. This is definitely a last resort as I do not think winning a National Championship(at least by me in the new DS with the AWD Audi TT on 285/20/18's) is possible with super soft rebound up front.

3) 19mm Hotchkis 3 way adjustable bar - This is the next test unless I decide to have the extender made for the 25mm hollow bar. I really think this would resolve the throttle cut off, but, I'm not sure if I would like the rear being that soft. When compared to the JCW 18.5mm bar, this bars center hole is in the same position, so, the center and inside holes would be stiffer than the JCW bar, I'm not sure if the outside hole would be as stiff or softer than the JCW bar..... I called Hotchkis 4 times with no clear answer on what the % of stiffness is compared to the OEM bar(and clarification on which bar it might be compared to, 17mm, 18mm or 18.5mm rear bar). Maybe they don't even know, that would be my guess since they are not returning or following up on calls that I have made(called them 4 times now)....

Anyway, next event is at Lincoln Air Park this Sunday. If I can get my Mini ping issue resolved at the dealership Friday, I'll make the trip up there to try the next setup change. Hopefully whatever I try next will be the resolution, Nats is quickly approaching!!!!! ;-)

 

Have you considered the Tarrett rear bar? it offers a wider range of adjustability than any other Mini rear bar I know of.

My 2007 MCS is on 3 wheels for pretty much every single element. For example:

http://autox4u.zenfolio.com/p8187524...1f1a#h20911f1a

People watching from outside the car have described to me my car balancing on 3 tires for tens of yards around long sweepers. My street tires are spinning off of every tricycle apex, and I have not felt the power cut that you describe yet.

So either something is different about the programming in our 2 cars or your R compounds are making the ECU behave that way.

 

Thanks for the info! No, I have not really looked at the Tarret bar, although, maybe I need to.

Do you have ASC or DSC?

I was also told that there are additional sensors in DSC cars, possibly with a lateral G sensor. If I am exceeding the lateral G's with the wheel in the air and wheelspin, maybe that is causing the issue?

None of my 2007 Mini's had this issue, but, I had a smaller bar and ASC.

If you have ASC, I'm betting that ASC/DSC is the cause of the issue.

 

My car does have DSC.

 

Before you throw any more money at the problem, I think the best test for you to tell if it's your R tires or the car's programming is to do some runs at an event on street tires with the rear shocks and rear bar set stiff to make sure you really get it up on 3 tires. If the power still cuts, you know it's the car's programming. If not, then you know it's a function of the sticky tires causing a scenario that confuses the car.

 

I've been struggling with mine all season. I have not had the loss of power you describe, although I have noticed something a couple times during the 1st to 2nd shift off the line where something seems to kick in and cut power, but my car is no where near being upset when it does it...I hold my button down to disengage TSC and DSC.

In any case, with my car chassis supposedly stiffer, not sure how much info transfers over to the hardtop. I lift my rear really high...all the time. People say it doesnt look right. I have the hollow comp Hotchkis bar and have run it on all three settings. My SA OTS Konis in the rear are set at 60% from soft. I am now running the bar full soft, and still not happy with the rear. It just doesn't seem planted and wants to do its own thing as opposed to following the front. I was thinking of trying to add an extension onto my bar to soften it another notch as well...or go back to trying the stock bar. It's also been suggested to put a bigger bar up front to reduce my wheel spin (ELSD). I still don't have JCW springs yet either so not sure how much more time I am going to spend tinkering until i get on the red springs.

As it sits, I don't have an issue with rotation as a lift is enough to get the rotation, but the rear doesn't instill confidence at this point. the last event I took all the shock out of the fronts and it seems to help a bit, but I like it a bit faster with a 1/2 turn or so dialed in so I want to be able to settle the rear and still have some shock dialed in up front.

I'm NOT very good at interpreting what the car is doing and what specific adjustments to make, so not sure how much value any of my feedback is...

 

Does the car have wheel speed sensors on each rear wheel, if so could you possibly trick the cars computer by linking them so when a inside wheel lifts off the ground the car does not know, by taking speed input from the wheel that still spins, this would allow you to at least see if it's wheel speed related because your high G-loads the Yaw sensors may think the car is about to rollover, there may be limits on G's that normal techs won't know about and Mini engineers did not expect such performance from any normal drivers, maybe you email Mini Tech or even one of the Race Teams and see what or how they over came this same issue.

Just a thought.

 

That car looks awfully familiar! Did you perhaps run the Northeast National Tour with it recently?

 

That was me Charlie, 3 wheeling at every corner, Nationals in a few weeks. I did some further tinkering and feel MUCH better with the setup now so decided to make the long journey out to Lincoln. I at least want to catch Todd Kean who's been kicking my *** all season in that G35.

 

Sweet there will be another Coupe there! I'll come and find you since I'm running DSP later in the week.

 

Good luck to you and to the Taz Devil too!

Kind regards,

Charlie

 

Cool, I'm at the far end of row 3 with a pack of Philly folks so swing on by!

jeff

 

Craig,

Do I understand that your doing a fair bit of engineering, to replace the DSC/ASC system with the simpler ASC only solution?

Kind regards,

Charlie