Hello,

I have been bitten by the race bug. 3 autocrosses and a day at the track and I need some help. I do not want to invest more than I have to, but I need a few things to be right.
2011 MCS...
First- the brakes faded after 4 laps or so and I had an extremely tough time getting them back to operating temp. Now my pedal is much softer than before the track and I want to fix.
Second- the tires are 16" all seasons and burnt already. No worries though, I am planning a set of lightweight 17's with sticky summer tires. Problem is, I am getting too much wear on the shoulders of the fronts. My cold air pressure is 35 psi. Any lower and it will roll onto the sidewall. Higher and I get more understeer. Suggestions?
Lastly- this is more up to preference, but I am seeking a simple (read affordable) solution to the slight roll, dive, and dip in the suspension. I do not want to give up the characteristic Mini "let-up and rotate" attribute, I love that. Question is, are the aftermarket spring rates set up to provide neutral handling? If so, or not, which aftermarket springs give the most factory like weight distribution?

Thank you so much for helping a motorist out,
Aaron

 

Apparently your brakes overheated on track. If you didn't already start with fresh track-worthy brake fluid and pads, switching to some would probably help resist heat. Getting more air ducted toward the brakes would probably help as well.

All season tires are not very track-worthy (don't stand up to the heat and stress very well), so a good set of Extreme or Maximum Performance (Tire Rack words) summer rubber should work much better. A more track-worthy alignment should help with both tire wear and performance as well. More front camber should reduce tire wear at the outside edges.

MINI shocks don't have a good rep for high performance driving, so you might consider better shocks that are compatible with the stock spring rates first. A more expensive, but better, alternative would be to switch both with a set of coil-overs (springs and shocks that are matched, and adjustable).

I suspect that you'll also be advised to get a somewhat stiffer rear anti-sway bar, and increase rear tire pressures. I've never actually tracked a MINI (but have tracked plenty of other cars), so I don't know the specific details that I'm sure someone will soon supply.

 

When I went to a MINI event last time, the Cooper S they had was not doing well in terms of brake performance with the stock setup after a couple auto-x style laps. I've read the JCW brakes are fade free for the most part for track use. Jim's suggestion of pads/fluid should be a good cheap fix for now. You 2011 MCS should already have the stock front brake ducting/cooling - not sure if there is any improvement there. You might just have to do 2 laps at a time to prevent over-heating next time.

 

The brake pedal is always softer after a track day, I get the brakes flushed before every one. I've not had much trouble with brake fade, but I'm not trying to optimise the braking.

The only way I've found to stop the shoulders wearing is to pump up the tires more. For our track tires I'm up to 41/38 psi. On the road they'd probably be only at 33/31. The tires have stopped wearing unevenly, they're not wearing much at all now.

 

Wow, terrific feedback everyone!
Jim: Your suggestions strongly reinforce what I believe to be the solutions, thank you.
Walk0080: How accurate do you think you are on the JCW brakes being fade free? That may be a viable option.
Btwyx: You get the brakes flushed by a shop or do it yourself? Does this help with after track pedal squish?
aaron

 

Additionally, if I went the route of upgrading my discs, pads, (both front only) and fluid, would it be sufficient enough for my light track use and WHAT brands should I buy? I am open to everything as long as they are quality and they don't squeak.
Furthermore, I think the outer shoulder of my front tires wearing prematurely is due to not enough negative camber. I believe by lowering just a little (1") may correct the problem. What do you folks think?

 

I get them done at an independent shop, though I found do it yourself instructions, should I ever get adventurous: http://www.lonestarminiclub.com/foru...read.php?t=476

The pedal will be nice an firm after the flush, before the track day, and then softer after.

 

Do you know exactly why the pedal is softer after track use? Additionally, is the brake fluid resivoir supposed to be topped off?

 

I don't know exactly why the pedal is softer, I was thinking of accelerated aging of the fluid due to the high temperatures reached, but I could be totally wrong. As I understand it, a soft pedal is usually because of gas bubbles in the fluid.

The brake fluid reservoir should be filled to the indicated level.

 

I will have to check on my resivoir for the indicated level. Thank you.

 

When I had low brake fluid after a track day once (down to the MIN mark) it flashed up a disconcerting parade of icons on the tach, something like "!, brake, DSC, tires". The SA diagnosed low brake fluid, topped it up and its never happened again.

 

Brake fade versus "soft" (low) pedal: We may not all be talking about the same thing. I consider brake fade to be a reduction in braking or slowing effectiveness. Not only does the brake pedal feel softer/lower (the pads seem to contact the rotor at a lower pedal point), but the rate of slowing (braking efficiency) decreases. Thus, the driver either starts moving his braking points back (starts braking somewhat earlier), or goes somewhat easier on the brakes, letting them cool more between hard applications (as they said Jeff Gordon had to do at Richmond yesterday). That kind of brake fade is somewhat more disconcerting than simply getting a lower/softer pedal without losing braking effectiveness; it just comes at a lower brake pedal point.

The friction from hard braking causes heat to build throughout the braking system. Even with fresh track-worthy brake fluid, pads, and rotors, braking efficiency management (like tire grip management) may become a problem over long runs; and the on-track adaptation is obviously harder for racers to deal with (without losing ground) than it is for those just driving around the track. Some tracks are also harder on brakes because their configurations don't allow much time for brake cooling between hard applications.

Track-worthy brake fluids list both "dry" and "wet" boiling points. My understanding is that the dry numbers reflect what the boiling points are when fresh, and the wet numbers refer to what the boiling points become after being subjected to air and moisture "contamination" through normal usage. Thus, starting with fresh fluid, and bleeding or replenishing as needed, often helps prevent that sinking brake pedal feeling.

Stainless steel brake lines are another route to a somewhat harder and higher initial brake pedal feel. Under braking, the steel mesh around the brake lines restricts the amount of brake line expansion, thus providing a firmer brake pedal feel. The downside is that the steel mesh makes it harder to check for brake line soft spots and fraying.

 

Great advice Jim!
It is most certainly "brake fade" I am experiencing. The 2011 MCS's have larger brake cooling ducts, but I know there is a limit in the braking system itself if I am experiencing fade 4 laps in. My braking points progressively became far earlier than in my first 3 runs all while pedal became lower and lower. I truly don't care to throw down on a BBK and would LIKE to be able to resolve this for around $500 +/-. I can install everything regarding brakes by myself, so that will help on cost. Question is, as earlier stated, which brands do I go for?

aaron

 

Aaron: If you experienced brake fade on your first track outing, you're apparently progressing much faster than I was when I started out. But brake fade was the first car (as opposed to driver) limitation that I ran up against (street tires were the second car limitation I met).

I've never tracked a MINI, so don't know which brands to recommend for MINIs, but they're probably different from what I've used on my cars. I've been using ATE Blue (or ATE 2000, which is amber in color) fluid and Performance Friction 97 Compound pads. Pagid Yellow pads are also popular for my cars, but one of the EBC pad compounds (they make rotors too) probably works well for MINIs (someone with MINI experience can advise which). The other high-temp brake fluids include Castrol SRF (but expensive) and Motul. Check for high dry/wet boiling points.

The switch from street pads to track pads may require some adjustment in braking technique. Pure race pads (those with very high torque) may be more difficult to modulate; sometimes leading to "over-slowing" on the approach to corners. Serious race pads also generally wear faster, and wear rotors faster as well. They also make more brake dust, and squeal more upon lighter application (as on the street). The tracking compromise is a pad that provides at least moderate torque, but easy modulation, quick release, somewhat longer wear, and "is kind to rotors" (the words vendors often use).

 

Greatly appreciated Jim. I hope some Mini Sunday trackers chime in. As stated earlier, I am not a racer yet, at least in my Mini, so brakes that perform wonderful on the track, are quiet on the street, and last relatively long is the direction I would like to be heading.
Additionally, I thank you for pointing out the variances in modulation concerning different pads. I for one love progressive modulation in my brakes, tires, suspension, and engine tune, so that will be high on my list for questions.
aaron