Ok, so this has been discussed, but I want the guys and gals who really cook their brakes on track to chime in with their opinions, experiences, or thoughts.

I bought the Wilwood 11.75 "race" kit. It was excellent for my first two track days. On the 4th, the rotors were cooked and shuddering very badly. Don at DMH told me two things I should have listened to:

1. My 15in wheels, with no ducting, will never allow enough cooling to the brakes, and therefore, I will always have this problem.
2. The kit comes with rotors that are too thin to hold up to extreme track duty.

As I've done track days and seen people with similar Wilwood kits on other cars (BMWs, Minis, etc...) I noticed that most rotors were in fact thicker, and I've even found people with similar experiences.

I went to the track last weekend with brand new rotors. By the third day, they were shuddering badly under hard braking at high speeds. They do not shudder on the highway.

I am running the Poly B pad up front with the Porterfield R4 in the rear for track duty.

Should I get cooling and move on to a more beefy setup, or will ducting help out? Would it be wise to move to a 16in wheel?

Thanks for your thoughts...

mb

P.S. - I should say, when it's working well, the kit's stopping power is impressive, and I've NEVER felt a HINT of fade with it.

 

I ran into the same issue with ducting and very open 17" wheels. It does depend on the track too. One track I go to I never had any brake issues, but another with really long straights terminating in slow speed corners played havoc. Cracked rotors. Another guy that get 3-4 events from a set pads at the other track went thru a set of pads before the weekend was out at the faster track.

But to the point. Getting more air in there can't hurt, I'd look at ducting first because even with a thicker larger diameter rotor and bigger more open wheels the extra air will not hurt.

The ducts Way have help, but if I was to do it over again I'd get something that direct air in to backing plate instead of pointing the flow towards the center. There is not much room back there so one must be creative. I saw a setup on a car in the Pacific Northwest, the person doesn't post here or doesn't post here often but they do on BMW forum. There is also a guy here in Dallas that took the OEM backing plates and made then ducted. He used parts from you basic racing parts place to construct it. Might not be pretty, but it works.

Backing plates for a BMW

 

So long as you use the 15s your options will be a bit limited. I can provide you with a slightly wider rotor that will maximize the available width between the pads and that's about all. You cannot convert this to a 1.10" wide or similar.

The next move is to 16s where you can fit the supplied caliper spacers and raise it up to use a 12.2" rotor. In this case even the standard .81 wide will be better or we can do a custom wider one for that also.

I note that you reference the shuddering comes and goes however. That tells me that a main part of your issue is pad build up most likely from improper or inadequate cool down. Typically the rotor gets hot and when parked hot it bakes a small "hot spot" on the iron from the pad not being given time to cool also. Next run out: pulsation. Very seldom does a pad brake well but pulsate with continued use as the temps push the pads to their limits they simply don't work well any longer. But that won't make them pulse.

I'd add the duct work but I'd also look at the cool down time as critical also. Back off after the checker and nearly coast back to the paddock. Push the car a bit after you park it for a few minutes. And if you really feel temps are an issue we can move you to the A compound which is a tad more stable at the extreme temps.

 

First and foremost, I'm an avid Carbotech fan and user. Let me tell you why.
First, their street pad probably has saved me from Deer 3 or 4 times. Second, their autocross pad made me unbeatable in my class, even allowed me to beat many Porsches and Vettes, even then, only the instructors themselves beat my time. Third, their track pads are unbelievable, unbeatable and have never given me any problems (once I learned to bed them in properly). In fact, the effectiveness of their race pads (XP10 anmd XP8) probably kept my car from turning into a wadded up ball of steel and plastic (little carbon fiber too). Back in May, I had a caliper brake mid sesion, I was moving very quickly, tires were hot and sticky, track was fast and I was putting down some good times. The caliper broke somewhere between my 6th and 7th lap, I began to notice a severe push in left handers, my right front was not sticking like it had been, knowing my tires were not very old and had lots of meat left on them I continued on for a couple more laps. When my lap times began to drop 2-3 seconds I came in. Took right front tire pressure, it should have been around 42 pounds, it was off my gauge, which goes to 65 pounds, I was probably was close to blowing the tire and didn't know it. The tire itself was extremely hot to the touch and was radiating heat 2 feet away. I checked the left front and it was really cool, to cool. Upon further inspection I discovered my left front caliper had actually broken and was no longer functioning as it should. The front right tire was doing almost all of my braking, the rear had been working extra hard too. I figured I did 3 fast laps with only half of my front braking power. It did cook the rotor, but that is a lot cheaper than wrecking my car.
After all of this I talked to the CT staff and further discoverd that their pads are engineered/designed to remove heat from the rotor, one of the reasons they dont tear up rotors, I had the same rotors on for 2 years up to that point. Track, autocross and 50,000 miles.
All this to say, I would suggest trying the Carbotechs before giving up on your rotors or Wilwoods calipers, they probably aren't the problem. I still have the stock brake calipers and rotors in and until I had that mechanical, never have had a problem. I hope that helped.

 

Thanks minimike - I don't know if carbotech makes pads for the willwood calipers.

Todd - thanks for the response. I do a cool-down lap, although this last weekend it was only about 1/4 of the lap. After that, I'd putter around the paddock very slowly. When parked, I'd move the car a couple of times before things got cooler. I felt like I took all of the precautions I could to stop either the warpage or the pad buildup.

I'm a little confused: my DP calipers can or can not be made to fit a 1.1 rotor?

When I say the shuddering comes and goes, I meant it comes at high speeds now (every lap) and goes at slower speeds.

Gnatster - I agree that the duct needs to be attached via a piece like you one you added in your post. That's why I'm tempted to get this one: http://new.minimania.com/web/Item/NMB4000/InvDetail.cfm

The problem with that, however, is that it goes below the control arm and will definitely tear off if I don't undo them and attach them higher when I'm not on the track. This might be a PITA, but it might also be worth it. Is anyone running the above kit?

Thanks for the comments, guys; I'll forego suspension updates this winter if I can get this tackled for next season.

mb

 

Makes me wonder if there is a balance problem on the rotor. I'd obviously not expect a shudder at high speed only. Hard to say.

The DP caliper will not take a 1.10" wide rotor. The max is 1.00".
A current .810 application however cannot be altered to fit the wider part. You'd need a new set of calipers and appropriate hat mods to convert this to the 1.00 wide. And rotors of course. All told prob about $900+ to do so. Better to sell this kit and buy new or you'd get stuck with the old calipers.

 

Mark, carbotech makes pads for the 11.75 calipers. I'd be very interested if anyone has any direct comparison to the XP's and the poly b's.


I've got XP8's or 10's on the rears, I just leave them on during track season, and take them off at the end of the season, and they've been very good on the rotors. Granted, these are the rears...

After I go through my next set of Poly B's, and next time I switch rotors, I'm seriously going to consider carbotechs on the fronts. Brake ducts are going in this winter, just have to decide the best route. I'm not so keen on the minimania ducts, but if they're easy to put on and off, it might be tempting.

Todd, I got the exact same thing Mark did with my last set of rotors--shuddering with threshold braking, and tiny cracks as well, probably way overheated them, as we talked about. I've had one track day on my new rotors, and I've been **** retentive on cool down laps, and moving the car a few feet once back in the paddock, we'll see how it goes. I really want to stay in 15 inch wheels, so I'm open to trying anything to make this setup work--the brakes are fantastic on the track, I just want to get a bit more out of the rotors.

And hey Todd--what would you recommend for brake ducts?

 

MB, I've been down the same path as you on 12.1" DP kit. I killed my on the 2nd track day. Have been just running on stock caliper with PowerSlot rotor and Ferodo DS2500 for the past 2 month. The front DS2500 last 3 track day, the rear 4 track day. By the 4th session of track day my Super Blue fluids are boiled and uneven material deposit starts to build up to the point where I can feel the shutter in steering wheel. I then call it a day and skip the 5th session. That video I posted was from the 4th session... It gets scatchy going into the hairpin turn at 95+mph.

I do have a new set of Plus4 Kit from Todd that I need to install this weekend, I have 4 more track days remain this season. Either with Stock or BBK, brake cooling ducts will improve the performance of brake system... I need to install one.

Here is the link to the MINI install. http://www.bmwpugetsound.com/vbb/showthread.php?t=30574

 

Thanks, that's the install I was looking for.

I wonder how much running 15" wheels is contributing to the heat buildup.

 

I've posted this picture many times, but I think I underestimated how much it really does affect it:



Toit like a toiger!

mb

 

No doubt the smaller wheels are inhibited the effectiveness or limiting the options. I'm not sure on the vibration issues. I really doubt either car is really overheating the pads. If the hats are now purple and the calipers close behind that I'd say it's possible.

No way around it; more mass is the key. Effectiveness is in the diameter- more leverage, swept area and overall mass. But with the smaller wheels options remain limited.

I can't comment on the ducts. You'll have to see what's out there.

Anyone have a link to the Carbotech options?

 

Not sure what you are looking for, but the site is www.ctbrakes.com and I know they can make pads for any brake system. Here's also a link to the compounds http://www.ctbrakes.com/faqs.html#compounds1 Hope that helps. Let me know if there's more I can do to help.

 

My hats are now purple, but the calipers are still black.

 

I was looking to validate cct1's statement:
"Mark, carbotech makes pads for the 11.75 calipers. I'd be very interested if anyone has any direct comparison to the XP's and the poly b's."
And see what they have for the DP caliper.

I went to their site and looked at the pads. I don't see this plate.
While their pads do have a good rep among enthusiasts I'm disappointed that they don't offer much real data on the pads. Let's see the real temp vs Cf charts for the compounds.

 

My bad Todd--I got the Carbotech's from the rears from Dustin, and I thought at the time I got them he told me I could get XP's for the fronts too. Somewhere along the line the fact it was for the dynapro must have got lost in the shuffle--a misunderstanding on my part, my fault, not Dustin's. Since Dustin posted on here, it appears you'd have to send them a backing plate for the carbotechs for the dynapro, not a big deal, but I wonder what the expense would be,the poly b's certainly are VERY reasonably priced...

I've been begging for a direct comparison between the poly b's and carbotechs on the dynapro's, now I know why one doesn't exist.

Ideally I'd be able to get 2 weekend events and 3 single day events out of a set of rotors--thats my season. I have no problem changing rotors once a year, but going through 2 sets of rotors a summer is more than I'd like. Might have to look toward going to a bigger brake set up, but like I said, I REALLY like the 15's....

 

We do have the backing plates for the Dynapro here's the pricing
1521 aka Bobcats, $99 this is a street pad
AX6 just for AutoX and putting passengers in the dash for only $115
XP8 Track Pads are $129
XP10 Track Pads are $144
Most of our customers run the XP10 in front and XP8's in the rear and only change out the fronts for street and some don't change them.

Todd's ?, "Let's see the real temp vs Cf charts for the compounds." I have asked CT to address this and once I get the reply I'll post it here.

The CT pads are hand made in NC by family members.

 

Me too! You know, I'm at these track days watching E30 M3s tear everything up on 15s, as well as every other E30 running smaller wheels. I think to myself, how come they don't have issues? A lot of them run Wilwood stuff, too.

I'm going to try to convert to a 1 inch rotor this winter. As far as I understand it, we'd just have to machine the hats. I'm hoping this will mean I can keep the 15s - if not, I have some extra r84s lying around waiting for track duty.

I'm also thinking the mini mania duct kit is a good option as long as you don't mind removing the inlet thing and attaching it higher for street use.

One part of this equation that I'll never understand (unless Todd chimes in with some really simple explanation) is how brake bias is involved in all of this. Last time out I tried to get as much pad in the rear as I could to balance things out, so I went with a Porterfield R4 on the advice of the guys at Texas Speedwerks. All around braking was better, but I have no idea if I still have "too much front brake" running the poly Bs. Running BP-20 (front) is not an option considering they literally incinerated at Jefferson in the beginning of the season.

I wanted to get the R4 for front and rear, but Porterfield sent me the wrong pad and I didn't have time to get it corrected. Come to think of it, I still have to do that!

mb

 

I've had the exact same thoughts with the E30's--my instructor at Road America was running 15's on an E30, and Wilwood's, with no problems. This was one of the reasons I went with this kit (I had JCW brakes at the time).

As for the Mini Mania kit, I wonder if there's enough room to tuck the inlet behind the front lip of the bumper when off the track. It would be nonfunctional, but it would be easier than taking it on and off all the time. Ny suspicion is this wouldn't work though. However, if the kit is really easy to put on and off, maybe I'll go that route. Its just that changing wheels and brake pads, and then fooling with brake ducts at the track, at some point time is going to be a limiting factor.

I've been very happy with the carbotech's on the rears, but they were on the rears when I shredded my rotors at Blackhawk. I talked to Todd directly about better pads on the rears, and because of the brake bias/weight shift during threshold braking, putting better pads on the rears still will make minimal difference overall to wear and tear on the fronts. As for a wider rotor, that should help, but again when I asked Todd about it, he didn't seem it was a great bang for the buck (Todd, correct me if anything I wrote above is wrong).

Dustin, thanks for posting prices. The carbotech's are a bit pricey, but if they are rotor friendly, they may be worth it. But we're going to need some direct objective numbers, and someone with experience on the track with both to sort it out definitively. I can say though that I'm happy with the carbotechs on the rears, they (and the rotors) are holding up nicely.

Anyway, just another thanks to Todd, who has been incredibly helpful both here on the boards and over the phone, and also Dustin.

 

TSW had a brake kit for a while, and I know they previously ran the Wilwood setup. I wonder if they made their kit as a response to these very problems. If I remember correctly, their kit had very thick rotors and still had the ability to fit under some 15 in. wheels. It's not on their website anymore.

I saw a GP with the Detroittuned Outlaw kit - he said he'd never had any problems with it. It looked pretty serious.

I don't know about "bang for the buck" with going for larger rotors. I'd have to buy new rotors (1 in.) which should fit with some modification. I think it's at least a step in the right direction if added with ducts. If it doesn't work, all I did was buy rotors which I'd have to buy anyway.

We shall see. We could just slow the hell down out there NAH

mb

Edit - I think there's a market out there if someone wants to make a thick-rotored kit plus ducts at a decent combined price. Oh, and make it fit under 16s at the minimum.

 

No big deal on the pads. I just wondered if they did in fact have pads for this. I get asked what options are available and would make note of it if they had them.

So from reading this there are FOUR options from CT for the DP caliper. Are they readily available or custom order?

 

The smaller kits obviously put less front brake bias into the car than a larger kit. However the larger 13" kits are produced with less piston (less clamping) area to counter act the larger rotor (greater leverage). Moving from 11.75 to 12.19" is a marginal change in bias.

For the most part I push folks to do alternate rear pads based not on biasing needs but on temps. The stock pads won't hold up as well when the rear rotors become heat soaked. For that reason I suggest the rear rotor kits for those with 13 front kits and using stock pads out back to begin with. The greater rotor increases rear bias but also more efficiently due to the total mass.

Where I think folks go wrong it to go larger rotors out back and track pads with them. You just won't use that much brake in the rear of a MINI. How much should you use; until under trail braking you feel the rears locking up. That's all she's going to give you.

With that in mind I feel the MINI can exploit some gains in the front as it's the only place you will get gains. On a longer wheel base car you can apply more rear brake just due to the dynamics. Still in the end it's less about "more brake" and more about "repeated braking" as many folks feel the stock brakes are not that bad either. Same principals apply here to the 11.75; it's running a higher duty cycle than a larger kit thus has less reserve.

 

Most of the CT pads are made to order. Please allow 5-7 biz days for pads to be made and maybe more during the peak racing season.

 

Both my 11.75 and 12.2 can be built with such a rotor- a wider 1.00 part. The limit here is wheel clearance compromise and caliper options. I can't really do a 1.10 wide rotor as we don't have a caliper bracket package to do this. That being said it could be done with a DL caliper however I won't put a racing customer out on pads that are only .49" thick.

And the TSW kit I believe had/has a 1.25 rotor. But not sure about fitting 16s. This is a lot of rotor for the car for sure but if you want wider it fills the order.

The TCE 3/4 kits are .810 and 1.10 kits where the .81 is quite effective in this size and a reasonable compromise on wheel clearance. The 1.10 wide takes up far more room as do some of the other brands.

 

Oh I didn't even think about that - if I get a 1in wide rotor, I'll need to get some new pads if they're not worn down enough, right?

You're absolutely right about "repeated use." In that area, I have ZERO complaints about this kit. And to be fair, the shuddering on the track at my level really isn't as terrible as it is annoying. I'm not racing for trophies here, but I would like to get better rotor life.

Thanks for the bias explanation. That makes more sense.

mb

 

Not quite. Back up a bit. Remember that you cannot fit a rotor much over .850" in the caliper and run new pads. Now if you went to totally worn pads you might push that to .900" or so before the rotor hits the caliper body. But to do a 1.00+ rotor you'd need to move to a totally new caliper sized for a wider rotor and begin the process all over from that base size.