My E90 M3 Dedicated Track build (with pix!)

[dogbone]

Originally Posted by M3 Number 86

I know the exhaust paths are different because 335i but I've been eyeing these guys. Flat bottom. Easily detaches.

Looks really nice. Are they considering an M3 version? Even if they are, I doubt they'll make a sedan version......

[M3 Number 86]

Originally Posted by dogbone

Looks really nice. Are they considering an M3 version? Even if they are, I doubt they'll make a sedan version......

The original build was for their sedan so hopefully sedan. Haha

[dogbone]

I had a chance to drive my new AP Racing Essex Radi-CAL calipers (front kit) this weekend at Buttonwillow 13CW with Speed District.

I was able to make a direct comparison between the new Essex kit and my old Stillen AP CP-5555 kit because the two kits use the same brake pad shape (and I was running familiar tires--Pirelli DH). I was able to use a new 18mm set of Cobalt Friction XR2 pads that I already had sitting here. (The Essex kit's pad shape actually requires cutting off a tab from the Stillen kit's pad backing plate, but the shape and size of the pads is the exact same. This Essex kit can take 25mm pads.)

I wasn't going in expecting much more power from the Essex caliper, but I have to say, the Essex kit is capable of delivering more initial bite than the Stillen kit did with the same pad material. I was able to make the Pirelli DH howl/squeal if I pressed the brake pedal quite hard at 133 mph on the front straight. I don't recall doing that with the Stillen kit. And the modulation in the pedal was very good. Pad knockback at the Bus Stop corner seemed less than I used to get with the Stillen kit. And they're darn smooth! Overall, everything felt like a step up.

The braking feel overall is a bit different. Not bad. Just different. The feedback you get through the pedal is different. I can't say I'm too surprised.

I was building speed throughout the day, learning to trust the new kit more and more with each session. Every pedal press resulted in smooth reliable braking. By the end of the day, I was braking pretty late and the brakes were still good for it. My last hot lap of the day was a 1:48.16. This is within 1/10 sec of my best time at Buttonwillow. Sadly we lost 30 minutes at the end of the day due to a Miata losing a wheel and needing a lengthy tow......argh.....At the end of the day, I really got into a good groove/zone and I think I could have been a bit faster if I just had a few more minutes.....

Ultimately, I don't feel I got to the limit of the brakes, meaning no matter how late I braked, I never felt in danger of leaving the track surface. It will take a bit of time to sort it out, but I believe I'll be experimenting with later braking zones. It was muddy around the track yesterday, so I wasn't in a mood to overly push the limits and get stuck in the mud. I never touched a wheel to the dirt all day.

Anyone who knows me knows that I was very happy with my Stillen AP Racing kit. But these new AP Racing Radi-Cals are another step up in braking technology. Given that I came from very good brakes and can feel a solid difference, I think it would be a pretty wild experience going from stock brakes to this setup.....That would be a mind job!

Oh, and my brake bleed felt good! YAY! (Still hate doing it though.....)

[roastbeef]

very interesting. i'm curious to see if you notice increased pad wear. jordan yost and i talked about brakes last december at willow springs. i'm tearing through pads like they are butter... i got two days and two sessions out of my cobalt xr1's and almost ran them down to the backing plates. jordan and i talked about a lot of things regarding brakes, but he mentioned that the J-hook design is pretty brutal on pads, but it helps with the bite. i was interested to hear that you noted more bite with the same pads and same pad shape. there are other variables between the kits, but i would think the rotor slot pattern change would have the biggest influence.
andie told me how long you run a set of rotors... i wonder how fast you're going to go through pads now. i'm sure you're pretty in tune with pad consumption rates on your previous kit, i'd be interested to see how much your pad wear increases.

[dogbone]

Originally Posted by roastbeef

very interesting. i'm curious to see if you notice increased pad wear. jordan yost and i talked about brakes last december at willow springs. i'm tearing through pads like they are butter... i got two days and two sessions out of my cobalt xr1's and almost ran them down to the backing plates. jordan and i talked about a lot of things regarding brakes, but he mentioned that the J-hook design is pretty brutal on pads, but it helps with the bite. i was interested to hear that you noted more bite with the same pads and same pad shape. there are other variables between the kits, but i would think the rotor slot pattern change would have the biggest influence.
andie told me how long you run a set of rotors... i wonder how fast you're going to go through pads now. i'm sure you're pretty in tune with pad consumption rates on your previous kit, i'd be interested to see how much your pad wear increases.

Without traction control, I got 39 days out of my last Stillen rotors, and I was getting 13-15 days out of a front set of 18mm pads. When I used traction control, I used to get noticeably less life out of them---around 25 days from the rotors and about 9-10 days from pads.

I think it's also important to note that my car has been lightened quite a bit, which also helps my situation. And given that you are taller than me and built like a linebacker, I'm lighter than you as well. That could be a total of 400+ lbs difference on track. I'm guessing that the XR2, being a lower torque pad than XR1, could last a bit longer due to being a different compound.

If you went though pads in less than 2.5 days, that would mean after day one you wore through almost half the pad. I only glanced at the pads after I was done on Sunday, and they certainly did not look like they were nearing half. (The transponder system says I ran 33 laps on Sunday.) For testing and curiosity sake, I guess it's good that i started with an 18mm pad which allows a direct comparison to the old kit's wear rate. Originally, I did not want the 25mm-capable version of the kit---more money, heavier kit, more expensive pads. But I'm glad Casey convinced me to go that route. Whatever the wear rate is, and i'm sure it will be fairly high, the 25mm will simply last longer, and they're really not much more expensive than the 18mm.....I think like $50-60 more. (Cobalt Friction is making a set of 25mm pads right now.)

I guess it's also worth considering how aggressive the driver is with the brakes. A novice driver could torture the brakes quite easily and put in slow laps. And a pro might fly and be quite efficient with them. So, looking at a driver's braking characteristics could have value.

Anyway, I have also wondered if the J-hooks act as a cheese grater. I guess we'll find out! They're great so far!

[roastbeef]

well, i still consider myself a novice. i'm sure i could use a little work on my braking technique. traction control is taking its toll on the pads for sure.
i went to laguna and then sonoma, and they are pretty hard on brakes. sonoma triggered mdm a lot, so i'm sure that didn't help.
anyways, i'm still excited to see your continued wear rate.

[mnelson3]

dogbone,
why did you choose the Essex radi-cal kit over the Stillen radi-cal kit?

thanks

[dogbone]

Originally Posted by mnelson3

dogbone,
why did you choose the Essex radi-cal kit over the Stillen radi-cal kit?

thanks

Stillen is widely known as the distributor for AP Racing's street oriented line of brakes. Essex didn't even sell brakes for regular production cars like an M3 until just a couple years ago because they focused only the race world. The kits that Essex sells now focus solely on track use.

When Stillen released their Radi-Cal several years ago, they originally said it was for 19" wheels. I knew the main AP guy over there, Jim Hodgman very well. He said he fought that idea knowing that they would alienate track guys. But Stillen put it out like that anyway. Then, later, they back tracked and said that the kit did in fact fit "certain" 18" rims. I have all Apex ARC-8 rims. Guess what 18" rim didn't fit? The Essex 25mm Radi-Cal fits my ARC-8 rims just fine-----even the 9.5" rims. In looking at the Stillen website tonight, Stillen is claiming that the Radi-Cal 2 was engineered for 18" rims----if you use the smaller 370mm rotor. The "standard(?)" rotor is 390mm. The rear is 380mm. I don't see an option for a smaller rear rotor. So, if you opt for the smaller rotor in the front---going from 390mm--->370mm, but you don't change the rear rotor size, you'll actually be running a larger rotor in the rear---370mm front, 380mm rear......it makes me wonder if you're messing up the "originally intended" brake bias.....

If you look at what it takes to change a brake pad, the Stillen kit is just not nearly as easy as the Essex. The Stillen kit has 4 bolts on each caliper. Two of them turn with allen wrenches and two of them HAVE TO BE HAMMERED OUT. AND TO HAMMER THEM BACK IN, YOU HAVE TO HAMMER FROM THE BACK SIDE!!!! My current Stillen AP rear kit has these hammered pins and I am quite sick of banging on my AP rear caliper with a hammer. That is just the DUMBEST god damn feature. I cannot tell you how much I hate them. I love my old AP kit, but I HATE those hammered pins! The Essex 25mm kit has a special quick release tension bridge that you can install, and it requires no tools at all to switch pads. So awesome.

Dust boots---the Stillen kit has dust boots......Dust boots don't stand a chance against track temps. I don't care if they call them high temp dust boots. I have them on my rear AP kit. One track day and they're fried. Those are totally a street kit feature. No silly dust boots on the Essex kit.

The Stillen "regular" rotors are MASSIVE compared to the Essex kit. 390x36mm vs 372x34mm. And Rear, 380x28mm vs. 340x28mm. I have to imagine that the Stillen rotors weigh more than the Essex version. And I can tell you with great confidence that there is no shortage of stopping power with the Essex kit. (Again, there is a 370x36mm option for Stillen which lowers the weight, but how does that work with a larger 380mm rear?)

Essex seems to have put some thought into anti-knockback springs which is nice. I can't find any literature on the Stillen kit to tell me if they have them too.

The Stillen kit comes in two super shiny colors that won't stay shiny for long on track. The Essex kit is all business with a simple flat Gray finish that I'm guessing will hold up better.

Regarding servicing calipers for rebuilds, I called Essex and they claimed they are used to turning stuff around in 1-2 days since they work with race teams all the time. A couple of us have had Stillen rebuild our Stillen AP calipers. They did not turn them around in that kind of time. Sometimes, just getting time in their shop takes 2 weeks. Plus, Stillen's rebuilds seem to be more expensive from the pricing I've gotten. We were paying about $200 per caliper all in for parts and labor at Stillen. Essex claimed they are less.

The Essex kit does cost more than the Stillen offering. The full (all 4 corners) Essex kit with 25mm fronts is around $1300 more than the full-sized Stillen kit. But since I have a track-only car, the Essex kit felt like it made more sense for my purposes. (Right now I still only have the Essex kit on the front.)

I give Stillen credit because they released the Radi-Cal kits several years ago---long before Essex, and they're already onto Radi-Cal 2. But I think it's pretty clear that the Stillen stuff is made to impress and be blingy on the street. The Essex kit is ready to get down-and-dirty on track.

Now, don't get me wrong------I LOVED my older Stillen AP Racing CP-5555 kit. And I don't have anything against Stillen. Heck, when they were developing the first Radi-Cal kit, they asked if I would be willing to bring my M3 down there so they could confirm some measurements, which i did. (They didn't tell me what it was for.) But, my old kit was aging and Stillen didn't stock parts anymore. As I complained previously, the parts were 10-12 weeks out......Would they even be available at all in the future? How long would Stillen support these Radi-Cals? They're already onto Radi-Cal 2.....what does that mean for the old Radi-Cal 1? Essex claimed that they are committed to keeping parts in stock for this Radi-Cal kit for a long time. I guess I'll just have to take their word for it.....

Hope that helps.

[mnelson3]

very helpful! your new brake kit looks fantastic, and i like the mat grey finish. my cars not a dedicated track car, but it seams the only time i drive it is on track days.
i talked to both Stillen and Essex last week, trying to see if this kit will work with oem 18" wheels. i have two sets, so i could go 9 1/2" square.
hope to see you at the track again soon!

[dogbone]

Originally Posted by mnelson3

very helpful! your new brake kit looks fantastic, and i like the mat grey finish. my cars not a dedicated track car, but it seams the only time i drive it is on track days.
i talked to both Stillen and Essex last week, trying to see if this kit will work with oem 18" wheels. i have two sets, so i could go 9 1/2" square.
hope to see you at the track again soon!

There's no need to guess if the Essex kit will fit. Print the templates that Essex has on their site. They are VERY helpful, and gave me no surprises when I mounted my wheels.

Here's the template for the Essex Radi-Cal 25mm front kit: https://www.essexparts.com/storage/w...l_template.pdf

Here's the template for the Essex Radi-Cal 18mm front kit: https://www.essexparts.com/storage/w...l_template.pdf

Make sure your printer prints at 100% size.

[mnelson3]

looks like i'm going square on the oem track wheels, maybe even a small spacer.

it clears my street wheels (Volks TE37SL) easy.

thanks again!

[dogbone]

Originally Posted by mnelson3

looks like i'm going square on the oem track wheels, maybe even a small spacer.

it clears my street wheels (Volks TE37SL) easy.

thanks again!

Great! And are you thinking of the 25 mm kit or the 18 mm kit?

[mnelson3]

just ordered the 25mm kit from casey.
should be here next friday!!

you should get a commission. ha

thanks again

[dogbone]

Originally Posted by mnelson3

just ordered the 25mm kit from casey.
should be here next friday!!

you should get a commission. ha

thanks again

Oh! Awesome!!! You will love them!

What pads will you run?

[mnelson3]

Ferodo DS1.11

your thoughts?

[warp10]

Originally Posted by mnelson3

just ordered the 25mm kit from casey.
should be here next friday!!

you should get a commission. ha

thanks again

Picked up my set today from Essex. Like that their east coast!

[dogbone]

Originally Posted by mnelson3

Ferodo DS1.11

your thoughts?

I have not driven DS1.11, so I can't comment on them.

I have had good luck with Cobalt Friction pads. I learned about Cobalt Friction from a race shop owner/master tech who was an active racer. He was quite knowledgable, and basically he said to me that Cobalt Friction pads had great stopping power, were easy on the rotors, were consistent lap after lap, had good wear rate and that they were popular with experienced racers, but not well known in the HPDE community because they don't have hardly any marketing.

I decided to try them, and I liked them. They have quite a bit of power, but you can modulate them. And they are reasonable on the rotors. I got 39 track days out of my last rotors. And the pads were going for 13-15 days. And i think it's fair to say that I am not gentle with the brakes.

But here's what I really like about Cobalt Friction: Because it's a small company, the owner is active in giving people direct advice about what pads to run on their specific car, tires and driving style. He's a super technical guy that has a lot of experience in the racing world. He's the guy mixing the compounds. And he's not pushy or a bullshitter. So, you don't need to rely on advice from some unknown dude on a forum (wait---is that me??). You can get expert advice from the guy making the actual pads! That's pretty awesome considering how important brakes are, and how many choices there are. And prices are generally in-line with other quality pad vendors.

If this interests you, PM me and I can give you contact info. If not, enjoy your kit! Report back on your thoughts!

[roastbeef]

Originally Posted by mnelson3

Ferodo DS1.11

your thoughts?

not that you asked me, but i recently tried the ds1.11's. they were decent, but i found myself missing the bite of the dsUNO's. they didn't last any longer, either.
recently tried cobalt friction xr1's and i loved them- lots of bite. i might try hawk dtc70's next, but i have a feeling i'll be back with cobalt friction. great stuff, and i'd mirror what dogbone has said.

[mnelson3]

Originally Posted by roastbeef

not that you asked me, but i recently tried the ds1.11's. they were decent, but i found myself missing the bite of the dsUNO's. they didn't last any longer, either.
recently tried cobalt friction xr1's and i loved them- lots of bite. i might try hawk dtc70's next, but i have a feeling i'll be back with cobalt friction. great stuff, and i'd mirror what dogbone has said.

dtc70 is the only pad i have ever tracked. i have nothing but good things to say.

i never try to overheat / push my oem brakes, but i'm a late braker, and the dtc70's pads never gave me an issue.

i agree, i'll mirror dogbone.

[dogbone]

Originally Posted by roastbeef

not that you asked me, but i recently tried the ds1.11's. they were decent, but i found myself missing the bite of the dsUNO's. they didn't last any longer, either.
recently tried cobalt friction xr1's and i loved them- lots of bite. i might try hawk dtc70's next, but i have a feeling i'll be back with cobalt friction. great stuff, and i'd mirror what dogbone has said.

Feedback is always welcome here!

This build thread has basically become my running blog of my track/car experiences. I’m glad it spurs people to ask questions and give their feedback.

[dogbone]

Originally Posted by warp10

Picked up my set today from Essex. Like that their east coast!

Oooh! Aaaaaaaaah!

Very nice! Congrats!

So----are they on the car already? I couldn't wait! I put them on next day!

[warp10]

Originally Posted by dogbone

Oooh! Aaaaaaaaah!

Very nice! Congrats!

So----are they on the car already? I couldn't wait! I put them on next day!

Monday.

Went with the big beefy pads and DS11.1 pads. Few other things to add on. But will have on track soon.