Not all the BBKs require wheel spacers.

The TCE DP caliper kit, now defunct, stolen by Wilwood (lol) and reproduced as such by them rather than me, is based on a 12.2 (or maybe 11.75 depending upon who you ask) rotor of .81 thickness. Not the most all out of packages but more than adequate for most folks in light to modest track use and all autocross apps. Better than stock but not up to the level of the larger kits. The details of such are in the VENDOR POST. Please guys, I post this stuff so we can all share good information and complete information.

The TCE Street Sport kit DOES fit stock 17" SSR (?) wheels with the use of the supplied .090" spacer. Yes, it's a spacer, but slightly over a 1/16" at that. This package does NOT require some larger .250" or more custom spacers, put wheel bearings in heavier load or change the scrub radius of the car. That's going to be an issue for you over time. The rotor package is still .81 due to fit issues, but given the weight of the car, the increase in mass, the improved air flow, and the efficincy of the PACKAGE this is more than up to the task of all but perhaps the top few % of track users. For them we do offer the wider 1.10 version and this will aide the thermal issues even more. But it comes like the other brands with 'wheel issues'. I think I've come the closest to offer you "your cake and eat it too".

By all means yes, I do fully understand the issue of the smaller wheels for both gearing, braking, weight etc. I run a race shop, I deal with these issues. However I did answer the call of the 16s with the DP kit. And proved it to properly fit the 16" S wheel with no problem. The down side to brakes for the smaller wheels is the lack of mass to shoe horn in there and not loose this space for the caliper. Frankly I'd argue a smaller, fatter rotor over a larger narrow one any day. But the world doesn't work that way. We have limits to what can be put and where. Or financial considerations of kit price and or customers needing to buy wheels to fit. Hard to sell a kit for a car which in turn requires $1500 worth of wheels and tires. In this case we make the best of what we can, how we can.

I planned on a 12.2 x 1.10 package but in this case the mounting was messy and I was not satisfied with the result btw. Still it would NOT have cleared stock 16s so again we were up against the wall a bit.

Lastly, while not picking on any one brand you must understand that stock replacement rotors of alternate brands regardless of surface finish, unless they have different casting vanes, do not offer more thermal capacity. Better bite perhaps from the surface cleaning the pad, less weight maybe from being full of holes, cleaner looks with plating but the math is the math. You can't change the equation. The pads in enhancement kits are the key to the package. But as we stated they become in turn limited by the rotor they are used on.

Sorry, didn't mean to ramble so long...
I'll see if I can get my local here to sign on and post some feedback. At least the car will be here tomorrow for the rear kit. I can hold it hostage!

 

my rig has 16" wheels: volks 7" for the track (if I ever get there again!) and AK 6-1/2" for the street (SSR Comp wannabee's)

on the front, I have Tarox 6 pot calipers and very nice slotted rotors with aluminum hats (all from Promini) they were a fairly simple install. I have to use 1/4" spacers for the 6-1/2" wide wheels

in the rear, I bought the rotor Promini specified for 16" wheels, also slotted and aluminum hat; very nice but two problems:
1. the rotor and caliper re-locating bracket positions the caliper about 3/4" too far out in diameter to work with the wheel. I machined the OD of the rotor and made a new bracket and the fit was perfect.
2. the move of the caliper radially also moves it rearward enough that the emergency cable now binds. This was much harder to fix. I got enough inner cable length by modifying the adjuster at the brake handle end, but then had to make a sleeve extension for the sheath. It jsut barely fit, but works fine.

I can report that I have never seen fade (after a couple of hard track days). the pedal feel is not as crisp as I would like ( i have power bled them a couple of times), and I personally would like the action to come on more at the top of the pedal travel. (has anyone sourced a larger master cylinder?)

next trick will be to add air ducting for the fronts.

Has anyon else fitted larger rear rotors? And if so, how did you deal with the e-cable, which must even more of a problem for 17" wheels?

 

be wary of larger rotors on the same size caliper. pad overhang, and later caliper hangup are going to be difficult to prevent

 

Hi Todd,

From what it sounds like the Wilwood kit will fit 16" wheels. I was thinking of buying the AK Monza 16x6.5 (44mm offset) mentioned earlier. Would I need a spacer for this combo?

Thanks,
Patrick

 

I'll see if I can add a bit more info here for everyone. You may or may not agree with all my opinions and that's ok too.

Comments on pedal feel:
Your problem is that you have to much caliper. A SIX pot on a Mini?? I hope those are very small pistons. What are the sizes? Too much piston area= poor pedal feel and overbiased front brakes. Hence the need for a larger mc with less pressure and more volume. You can nearly always go to less piston area and be ok, but more is not a good thing.

Spacers:
Yes, 1/4" seems to be the norm. If done right with wheels of different offsets you can at least negate some of the bad things. Stock wheels also lose their hub centric design and you'd better see about spacers that put this back if at all possible.

* I'm also digging up info on a 16" wheel used on one of my Eclipse kits. They fit my 13 x 1.10 set up. You read that right.

Cable length:
Yup. Same issue will be here on my 11.75. I found enough slack in the cable by removing the anchors I think, but it's tight.

Pad overhang:
On a larger rotor? I don't follow. Yes you're correct that pad overhang can cause problems (pad material touching in time) but you won't get that on a larger rotor. Big calipers on small rotors yes.

Wilwood kit and 16s:
Yes their facory kit fits 16s from what they and I know of it. Same on my TCE kit for the car. As for wheel fit and such I'll defer your question on that now to them. I can only supply data on what I had planned and how it fit for my use. Their hat offsets and such make my excel program useless unless I know the specifics of what they have on the kit. I'd suggest you contact them directly and ask the fit, sizing of the rotor, and availability. I'm sorry to say I cannot offer you more than this on it at this time.

(I just finished squaring away the deal with my CNC shop on the brackets Steve has....prototypes, his and the studs; nearly $350...ouch. You should forget putting them on the car Steve and hang them on the wall!)

 

It's here! It's here!! I'm the guy who bought Todd's 12.2 TCE Wilwood kit folks seem so interested in. Unfortunately it's just sitting there, back in its box, taunting me...."Oh Steeeve, put me on the car...you know you want to."

This is maddening!!!! It's thesis completion panic week and I'm reviewing/editing my students' theses nearly round the clock so they can graduate on time....I have NO spare time for fun like installing this lovely new brake kit! In fact, the only "spare" time I have are the two hours a night I spend sleeping.

Oh well, maybe after I sleep straight through Saturday to catch up I'll have some time on Sunday....I can only hope.

So, the only review I can give you so far is it looks like a GREAT system....rats!

 

Tell us your impressions when everything is on :smile:

 

ooh this is good stuff. Thanks ToddTCE for the big help. I'll have to read through this again.

So far, if I've gathered it right:

*bigger volume calipers - bad idea
*pad material - very important
*cross drilled or any sort of holes in rotor - potential for cracking, which is bad
*slotted rotors - basically a good idea
*stainless lines and brake fluid - help pedal feel and fade but won't help stopping distance
*wider and shorter tires help stopping distance

 

Thanks for the Cliffs Notes Ryephile .

FWIW, I've heard a few folks say that ss brake lines do help with braking distance. And to be honest, theoretically at least, I'd have to agree. If non-ss lines (stock, for example) are being used, and one stomps on the retro-rockets, they will expand outward more upon compression than something of more integrity. With that, less force will be applied at the end of the line, where we want it, or at least that force will take a tad longer to get there...

And although many feel this to be true, not all want that though. I recall Randy stating somewhere that he prefers to have some "modulation" in his brake lines. I never pursued the reasoning or rationale with him, but I wish I would have...

 

for what it's worth, Tarox makes a 10 pot caliper for 17" wheels! (I didn't measure the piston area for the six pot)

for the rear, after machining, the friction surface on the rotor is still wider than the pad surface, just barely, due to the construction of the rotor.

 

The attached jpg should help explain how a larger rotor can create pad overhang. assume the 110mm block w/ the 255mm radius on the bottom is the caliper. now the 280mm arc below it cant go past the lower corners. this creates a 0.55 mm possible overhang condition. Unless the pad arc is changed, pad overhang can happen.
'nother thing...if you decide to change the volume on both the calipers and m/c, you are going to seriously affect the ABS's performance, and may even compromise it's ability to stop the vehicle at all.
also...front brake bias = good; rear brake bias = VERRRRRY BAAAAAD!!!!!
all vehicles are designed to be front biased. you NEVER want the rear calipers to lock before the fronts (remember rear wheel ABS for trucks?) if your front brakes lock, you just skid in pretty much a straight line; if your rear brakes lock, you lose all ability to control the vehicle.

shoot, cant get the whole image, I got enough to show the jist of what I mean, though.

 

I think I understand what you're driving at on that drawing. You'd have to make the rotor pretty big to achieve this however. I've done the 11.75 as a rear upgrade on three cars thus far and find the stock caliper to fit this radius pretty well. But yes, I see what you're saying. This is the same basic reason I cannot put the DP caliper on a 13" rotor- the radius of the caliper touches the rotor prior to the pad seating properly. If you change both the caliper and the mc and keep the raios the same between them you're not going to do any harm. The larger MC on the car with the six's may be the ticket but where are you going to find one to fit? ABS should stay fully functional on all BBKs, regardless of size. Since ABS measures rotational input from the wheel sensors and only 'knows' when one wheel stops turning. If this car (like the SRT4) has EBD, then there's more tweaks in the system to consider but even I admit; I haven't got that one figured out all the way. Most who really track that car choose to disable it for improved feel and reliable performance.

Ten pot calipers? I've seen the pics. Cool looking perhaps. Real value is in the eye of the buyer. Hope one doesn't have to do a rebiuld...lol

SS hoses- they don't do a thing for fade. Edit that part. Feel yes. Shorter distances maybe. The reason for any distance change is more likely due to better driver modulation than anything else. Not a direct link to more brake.

Too much rear- yup that's not good. But so too is too much front. When you have excess area up front you lower the required line pressure, this in turn lowers the line pressure to all the brakes, thus rendering the rears less effective as they could be as well. Another company makes reference to this in other ways.

 

your m/c to caliper ratio theory would be effective IF the ABS unit did not have a limited size dump chamber. The dump reservoir won't be able to handle much, if any, additional volume; and if the unit can't dump enough fluid to allow the brakes to actuate, it really won't matter how fast it cycles.
Yes, you have to go up by about two inches or so in rotor diameter before pad overhang becomes a serious issue. ( I just recently had a design issue with one of our calipers that we are packaging on both front and rear of a vehicle. front rotor is 365mm and rear is 390...boy was that a serious pain to work on)

 

Ah, I see what you mean. Learn something new everyday.

That rear project sounds like my customers asking for a rear kit for the Lightning. it's already 13"...and any caliper only change will result in pad overhang due to the nose of the caliper bumping the parking brake drum/hat. Sometimes you learn too leave well enough alone.

 

From everything i have read and felt in the car it does have EBD. I learned how to feel when it came into effect on my SVT and i've felt it on the MINI.

 

While we're talking about the front to rear balance, aka bias, I have a question or two:

How difficult is it to add a bias adjustment valve, and, if added, would it affect the operation of the ABS?

Is getting the bias adjustment set correctly relatively easy for a skilled, but non-professional driver? Or, would it be a recipe for disaster, i.e. too much rear bias causing nasty spirals at the end of the straights?

 

bias adjustment valves are already there. typically called a prop(ortioning) valve, they've been used for years.Up until recently, they were mechanical and dropped the rear/front pressure ratio at a predetermined line pressure, now with electronically variable valves, they help mostly in maintaining a front bias condition. Trucks used to have the biggest problem with the mechanical ones and no ABS, because of the position of the center of gravity of a truck, wven prop valves couldn't always maintain a front bias during both light-load and full-load tests. The MINI has (as previously stated) EBD, an electronic version of the prop valve, this, in combination with the CBC, would make another, redundant and manually adjustable (and extremely difficult to tune), really hard to engineer, not to mention operate without disturbing the electronic versions, wow, what an incredible question.

 

Agreed, the proposal to put in a manual valve shoud best be left for those who are buiilding a track only car with all the factory ABS/EBD etc. removed and contenplating brakes all the way around if not also including a twin mc and pedal assembly.

In addtion, the manual prop valve does offer better fine tuning and the opportunity to tune for conditions and car set up. The flip side is that you have to know what you're doing and how best to maximize the change.

Putting one in line to the rear might 'work' but its value would be certainly questionable. Granted I guess if you had mondo calipers and rotors out back that needed a big adjustment to line pressure it could be valuable, but that's a band aide solution in my eyes.

The experience I've heard of and seen on EBD is that this offers a 'funny feeling' on the track and in fact has pedals going to the floor or very soft on some folks SRT4s. Not knowing fully why this is if anyone can offer some ideas I'll certainly share them with the guys. They have found best results by way of turning off the entire package some how and running manual.

 

I think that the issue for tires and stopping distance is the relative "stickyness" of the tire's rubber compound, more than the tire's dimensional measurements

 

Smaller wheels will stop faster than larger wheels. Smaller wheels will accelerate faster than larger wheels. Same principle. Lighter rotational mass. This is a big big thing that many people overlook. 15 inch wheels for me! :smile:

 

--->polmear, thanks a ton for the info! Always good to have a well-oiled OEM engineer to keep the facts straight. Have you checked out the local http://www.michiganmini.com yet?

--->toddtce; thanks for your continued help :smile:

--->caminifan; I was speaking theoretically, as jazmini stated. Of course tire compound and tread shape will have to be factored into the whole picture.

 

Is getting the bias adjustment set correctly relatively easy for a skilled, but non-professional driver? Or, would it be a recipe for disaster, i.e. too much rear bias causing nasty spirals at the end of the straights?[/QUOTE]
Others have opined correctly on the fact that you really do not want to mess with a bias adjusting valve in your basic stock car cuz of the electronics.

so let us say you go and buy a set of Tilton pedals ansd masters and plumb them in. they would then more than likely sell you a mechanical bias adjuster which works by altering the relative lengths of the master cylinder pushrods.

Adjusting is fairly safe and easy given a pal and a wet grassy field. Have your pal stand to the side and you mess with the adjustment while he tells you which axle locked up first. You wanna get it so the fronts lock up a tad before the rears. that is your base line. You move the **** in SMALL measures to mess with it at the track.

AAAAND ANOTHER THING........<

pad material, pad material, pad material..... nothing better for a brake upgrade. Perhaps THE thing.

 

If rotational mass is the issue, then go with forged wheels (~13 lb/wheel for 17 inch wheel). Frankly, I am a bit suspicious of the gains that are being postulated for reduced rotational mass. Do you have any empirical data to back up the claim? I don't question the theory; only the practical application of the theory. For example, do you have any test data (say for 60-0 or 70-0 stops) where the only variable was rotational mass of the wheels? Personally, I think that rotational mass becomes more of an issue for the handling of the car - if there is less un-sprung mass to deal with, the handling is more controlable at the edge of the envelope.

Increasing brake torque is probably where you are going to see a noticable improvement in stopping distance. The usual route to increased brake torque is to increase the size of the rotors and the placement of the calipers relative to the rotors - hence a big brake kit. A further benefit of the big brake kit is that the rotors used in the kits are typically better at handling/dissipating heat build-up than the OEM rotors, which is why fade is less of an issue with the big brake kits. Unfortunately, the usual consequence of an increase in rotor diameter is a requirement for larger diameter wheels.

Regarding attempting to tune front-to-rear bias, I wonder about the cost of tires that are munched each time the reference is which corner of the car locks-up. Remember, each lock-up is a flat spot on the tire that locked up. Does that mean that you have to buy two sets of tires - one to do the bias adjustment and then a second set to replace the tires that have flat spots from the bias adjustment effort? That seems like quite a proposition to me. I doubt that the cost-benefit (e.g. $1,000 in flat-spotted tires for what, a 5 foot improvement in 60-0 distance???) is worth it.

One more question: If there is such a bias against cross-drilled rotors, why do the major manufacturers (such as Porsche, BMW, Mercedes, even GM with the DuraStop brake upgrade) feature cross-drilled rotors?

 

I'll relate.

I put a set of 18" wheels and tires on my F150 some time back. Bought them new, proper 'replacement sizing' as I didn't want any bs, just nicer looking wheels and needed new tires. Diameter was off by about 3/4" if I remember. Figured this would mess with the speedo a bit and it did. About 3mph or so, but not bad. What was bad is that the truck turned into a dog. Towing the race trailer it would no longer run down the highway at 75-80 without downshifting constantly out of OD. Before it had pulled OD quite nice and motored along with decent mileage etc. WTF? Hmmm. After I got back from the rpm trip from hell I pulled a wheel and weighed it. 70lbs. Then I picked the one good stock wheel. 45lbs. I had my answer. Just to prove it I pulled them all off and bought two new stock tires and put the stock parts on for the Pikes Peak race which was a longer haul. Yup, back to normal.

Think 25lbs per wheel/tire doesn't make a difference? It's huge. Granted I don't think too many of you will see these numbers but it did prove the point.

Got a nice set of MB Smooths and some Falkon tires with about 1500m on them if someone needs them....

Luckily brakes don't put on quite that much mass. Depending upon rotor width there is some gain in rotational mass and MOI which will effect performance but the trade off is less total unsprung as well as the brake improvements. There's a bit of a trade off that becomes a wash.

 

I've heard that most cross-drilled are just that... drilled-out after the production of the rotor. Apparently there are some where the hole-making is part of the fabrication process. It is with these (as I read somewhere) that stress cracks are not an issue...