Make sure your rear control arm is not cracked or broken. Several others are reporting that theirs is broken or cracked.

FYI.

 

JLM,


That's an interesting observation; do the Mini's rear wheels toe-out when unloaded - from braking? By contrast, VW's dead axle/trailing arm set-up toes-in under the same circumstances creating a very stabe braking plateform.

 

My MINI doesn't get squirrely with heavy braking going in to Big Bend, but I've experienced it at the end of other straights. Sometimes I've been able to identify some irregularities in the track suface, other times not. I have H & R lowering springs, 12/02 build, adjustable lower control arms for the rear (H-sport), and a 22mm swaybar on softest setting, though I've experienced the squirreliness before and after the swaybar. I had the factory specs for alignment after installing the control arms, though it's been a year. Sorry if this info isn't terribly helpful. How about for Big Bend, since you're not trailbraking, getting on the gas a little before turn in to settle the car?

Saw a race GTI at Summit Point in front of me going into turn 1 with the right, rear inside wheel lifting, it was funny, just kind of slowly going round while it was in the air.....

 

Tontobird - Are the H&Rs linnear or progressive?


Thanks!

 

The H&R's are progressive.

 

I had a lot of "squirrelly-ness" in the rear at Pocono (north), braking hard (in a straight line) heading into the in-field.This was last year, and everything was stock, and I am guessing it might have something to do with the heat of the tires and them subsequently losing grip unevenly...or maybe it was brakes. When I took my pads out, the rears had a lot of uneven wear, and if one side had gripped harder than the other under heavy braking, I'm sure that could have caused the feeling of looseness too.

Come to think of it, I've had to do some heavy braking at high speed on the highway too, while in a straight line...and I remember the rear feeling loose...maybe it is the rear brakes?

 

I've experienced this even on the street. When braking in a straight line, the back end does seem to get a little squirrely - almost like it wants to step out. Doesn't the MINI have EBD (electronic brake-force distribution)? Perhaps this system optimizes the braking force almost to the point of feeling like the back end is going to swap ends.

Did you have to catch the car from losing the tail in any of the braking zones, or did it just feel a little loose? I know it made me uneasy when I experienced it, especially coming from a RWD vehicle, but the vehicle was still braking in a straight line and I had no problems controlling it.

 

the reason I suspect the toe changing under heavy braking is from observing the movement of the front wheels under a hard launch; solved on my car by beefing up the contol arm bushings. I have yet to do the rears, but it is on my list; I have the powerflex parts.

 

If you have seen any of the Cooper Works Challenge race pics or videos you will notice that they have a rather large rear spoiler. Maybe the MINI needs a little help with more weight at the rear end.

 

In the few track days I have done, I would agree with this! I've been on the lookout for a decent rear spoiler.

 

It seems like a rear spoiler might help some, but I'm still expecting to find suspension or alignment woes. Pleae post whatever you find, Morefun.

 

jlm,

Did you install both lower control arm bushings? How would you describe the ride? I used poly, hard rubber and delrin in my last ride. Move were instantaneous, but punishing.

 

I would probably agree; most aero components require a fair amount of velocity before they even begin to work - say over 100mph. I don't think my squirelyness is from a lack of aero grip, rather, mechanical grip at the back end during hard braking.

 

Ii put in the Powerflex front control arm set consisting of a polyurethane outer and a harder plastic inner. much better than stock and not a punishing ride. get under your car sometime with a prybar (big screwdriver) and lever against the control arm near the bushing and you will see the flex.


the install is a bit of a chore; so while you are at it is the time to change your front sway bar (mine are H&R., front and rear, with teflon lined no-lube bushings)

 

How much of a chore is it? This is something I want to do myself also. Give me an idea of the steps you need to take to get this job done.

THANKS

 

I would think that a good wing would have some weighting effect as low as 40MPH. Figure you go into some of these turns at 60+, it just might do the job.

Better yet a well designed rear diffuser would be about the best mod. I think it was the M7 guys who played with a prototype (not the one they used to sell) and said the down force was huge. This is another thing I'd like to play with myself.

 

Actually the size of the wing shown here http://www.johncooper.co.uk/JohnCoop...sport%5FOther/ would work at fairly slow speeds. The larger the "attack" angle, the greater the downforce. Watch some of the Cooper Challenge videos and notice the lower speeds. The Coopers don't normaly see real high speeds.

Not saying this is the problem, but it could help.

 

onasled - do you have DSC?

 

Yea, but I do shut it off when on the track.

 

to drop the front subfarame (about 3-4 hrs out and back in):

jack up car high and remove wheels.
remove: headlight aiming sensor, swaybar to droplink bolts.
disconnect: tie rod ball joint at steering knuckle (needs a common puller) entire lower ball joint, intact, from hub (two bolts each). power steering resevoir brakcet to firewall
subframe attachments to chassis (8 or so) and to front crush tubes (4).
wiggle it down supporting it with a jack until you can disconnect the fan and power steering leads. the subframe comes out and brings the power steering resevoir with it, snake it out of there.

you can then access all the bolts for the sway bar, and control arm bushings, some are torqued to 120ft-lbs, so beef up.

 

I've done these on a few cars before...straight foreward, but a chore as you say. I imagine that turn-in and front end bite is much crisper???


Thanks jlm

Apologies for robbing your thread Morefun.

 

I would suggest adding just a touch of toe-in at the rear - maybe 1/8". The wheels (or bushings) will flex back and toe out a little under breaking. The slight toe-in will help compensate for that. You will loose a little of the edge in turn in though.

 

Thanks again guys - an interesting range of responses. Cheers,

 

morefun, did you find out the problem. I would like to know what happened in your case.

 

I experienced this problem twice before installing the madness rear bar, I keep it in the stiffest setting, also at the same time I discovered the right rear camber was +1 degree and the left rear was -1 degree. The lower arm was bent and I replaced with the solid aftermarket ones and havent had the tail-wag since.

I think the sway bar did the trick though as I tested it some before I recieved the camber bars and couldnt get it to wag.