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      03-31-2014, 11:48 PM   #1
The HACK
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Finally took the MZ4 Coupe to the track...Racing Brake Calipers

This season I'm starting with a significantly different setup than the last 3+ years on the MZ4 Coupe. The car now sits on squared up 275/35/18 Maxxis RC-1 R-comps, -3.5º negative camber & 2/10th" toe-in, aFe air intake system, and RacingBrake caliper upgrade on all 4 corners with XR-70 pads in the front and XR-60 pads in the rear.

Prior to that, the car rode on 245F, 275R Nitto NT-01 R-comps, -2.5º negative camber and 1/10th toe-out, stock air box, and stock calipers typically using Hawk DTC-60 (and last event, PFC-11 front/PFC-08 rear)

This post will be primarily on the RacingBrake caliper upgrade on all 4 corners. For my thoughts on the Maxxis RC-1 or the aFe air intake system, I'll write more about them on their respective sub-forums (engine/drivetrain, wheels & tires).

Out of all the changes on the car, the RacingBrake caliper probably is the most drama free. It did exactly as I expected. Consistent brake feel with much better modulation and release of the pad, excellent control, with zero fade even with the increased grip level. Pad change the weekend prior was extremely easy, with each corner requiring less than 10 minutes each, counting the time taking the wheel off. All of which I fully expected prior to hitting the track.

The best description I can give, is the non-linear feel in the first 30% of brake pedal travel is gone. Even with track pads, pressure on the brake pad doesn't build linearly with the factory sliding calipers. On the factory calipers the brake force sort of ramps up, making it difficult to get very precise with application, especially with the brake release leading to a sort of "on-off" feel when getting off the pedal. While this isn't a HUGE deal, it does make trail-braking a little bit more difficult in how you time the release of the brakes.

With the 4 piston front, 2 piston rear fixed kit from RacingBrake, trail-braking becomes significantly easier and CONSISTENT. I can now modulate the brake pedal for trail braking like I modulate the gas pedal for throttle steer. It's a small difference, but with confidence in trail-braking I find myself doing it more of it in more corners.

The other big difference is less pedal pressure is required to achieve the same result. I'd say the caliper upgrade reduces pedal travel by approximately 10-15%. The difference isn't huge, but it makes heel-toe a little easier in that my foot isn't pressed down nearly as far for the same amount of anchor dropping. It took some getting used to, and I found myself over-braking at first but within 3-5 applications my full confidence was back.

I was skeptical at first about running 2 different compounds front and back, but tire pressure in the pits showed that front and rear are working equally as hard since tire pressure were identical at all 4 corners.

The biggest benefit to the RacingBrake caliper, was the ability to simply run my stock wheels (well, squared up rears) without the use of spacers. The stock fronts would have required a small spacer, but with the squared up rears all around, the caliper upgrade required zero additional hardware and kept the offset up front reasonable.

The actual improvement was minor, because the MZ4 Coupe already had phenomenal brakes (for a BMW). The side-effects, however, were MAJOR. I probably wouldn't have ever bothered to try and fit the rear wheels withe the 275mm tires up front. I tried it only after installing the RacingBrake calipers to see if it can be a viable solution to running a big brake kit completely without the use of any spacers, and the hunch paid off big time. If I didn't switch calipers I probably would have been perfectly happy using the same staggered setup on NT-01s, which would remain at -2.5º camber.

The caliper upgrade kit definitely pass the track test. An excellent value if you've already upgraded to RacingBrake's rotor kit, and a good upgrade as a "big" brake kit if you buy it as a kit. Definitely more affordable than other brands of big brake kits on the market, and holds its own for high performance and race applications (for those familiar with Scott Cary's SCTS racing team, they've switched from StopTECH to RacingBrake on their 135i Prepared class race car).

http://www.1addicts.com/forums/showthread.php?t=965809

And the DRAMA he encountered with the 1 series Brembo calipers:

http://www.1addicts.com/forums/showthread.php?t=221203

Thanks to Scott for donating a set of Maxxis RC-1 scrubs for the whole experiment.

Pictures to follow this weekend.
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      04-01-2014, 01:30 AM   #2
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Nice write-up Hack.

Looks like we have another viable option for our cars and I'm glad the RB combo has panned out on the track. It always looked really good on paper.
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      04-02-2014, 09:34 AM   #3
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Thanks for sharing. Both my e46 m and my z4mc have had front and rear bbk's. Improved feel, modulation and fade resistance make every drive more enjoyable for me. Even more so on the track. Next time out with my coupe I'll be running squared 275 conti slicks so I'm very excited to see how this pad compound handles the extra grip. Same compound has been fine on the tts I track but it's about 200-300lbs lighter.
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      10-01-2014, 08:52 AM   #4
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Quote:
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Pictures to follow this weekend.
we've been waiting and waiting, Hack!







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      10-01-2014, 11:53 AM   #5
The HACK
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I think I posted the pictures to another thread, because I distinctly remember taking pictures an putting them up somewhere?
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      03-13-2016, 12:48 PM   #6
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Reviving an old thread.

Are you still happy with this setup?
You mention being able to fit these under factory wheels. Do you mean the factory 18's?

I'm looking for a minor upgrade since my stock brakes are done. I'd like to improve the modulation as you described and get the look of a BBK at the same time at the lowest cost possible.
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      03-14-2016, 06:43 PM   #7
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Quote:
Originally Posted by kav View Post
Reviving an old thread.

Are you still happy with this setup?
You mention being able to fit these under factory wheels. Do you mean the factory 18's?

I'm looking for a minor upgrade since my stock brakes are done. I'd like to improve the modulation as you described and get the look of a BBK at the same time at the lowest cost possible.
They fit under the factory wheels but will likely require an 8mm spacer to fit the front. I ended up running a set of rear wheels up front and they clear with plenty of space and no spacers.

It's not a cheap solution, by any stretch of the imagination. I believe, had I had to pay retail, the full 4 wheel setup would have set me back about $4K, rotors, calipers, and pads all said and done (no you may not ask how much I paid. Well you can ask, but I can't tell. Part of the perks of my day job means I never have to pay retail for ANY aftermarket auto parts). But it is more affordable than other 4 wheel "BBK" package out there, although you do get bigger rotors with most of the other kits, you don't with MY set-up.

RacingBrake do sell a larger, 14" rotor kit up front, I can't guarantee that 18" wheels will fit thought. Even on my stock 18's, I had to run the rears up front because the caliper interferes with the barrel of the wheel (if you look at the wheel you'll see the spoke side of the barrel is narrower) on the stock front. But that's almost universal with all big brake kits, I used to run a Wilwood kit on my E46 and that required a 12mm spacer to BARELY clear. Your mileage, with ANY fixed caliper BBK, will vary.

They're fantastic otherwise. Solid pedal engagement with better modulation over stock, I can easily change pads on all 4 wheels within 30 minutes. With their track pads (XP900 I think) it handles the hottest braking tracks on the west coast (Buttonwillow and Auto Club Speedway) with ease, although now that it's nearly 4 years in, I'm in dire need of new pads and are looking to switch to Cobalt XR3s (personal preference...it is what it is) Be happy to keep running RB pads if they're free, but I sort of miss the anchor dropping, eyeball gouging that the Cobalts do.
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