My E90 M3 Dedicated Track build (with pix!)

[mnelson3]

Dogbone,

i contacted Cobalt friction and Andie thinks the XR1 pads will give me a similar feel to the Hawk DTC-70 pads i typically use. do you think the additional bite from the j-hook rotors would make the XR2 pads an option? and as a side benefit, be a little easier on rotors.

thanks

[dogbone]

Originally Posted by mnelson3

Dogbone,

i contacted Cobalt friction and Andie thinks the XR1 pads will give me a similar feel to the Hawk DTC-70 pads i typically use. do you think the additional bite from the j-hook rotors would make the XR2 pads an option? and as a side benefit, be a little easier on rotors.

thanks

He seemed to recommend the same thing to roastbeef. I guess when someone talks about coming from a pad that has a high initial bite and wants to keep that characteristic, he suggests XR1.

I can tell you from personal experience that XR1 pads have a ton of torque/bite. A few years ago, my friend had a set of XR1 with the older Stillen AP kit (same as my old kit) on an E90 M3. He just bought them on his own without any advice from anyone. (This was before we knew that we could ask Andie questions.) At the time, he was running Hankook R-S3's. I drove that car. The pads were able to lock up the wheels pretty easily. ABS was kicking in fairly quickly. Both of us thought it was too much for his setup. Perhaps with a more grippy tire it would be fine, but he never got that far. He moved on to a Porsche.

When talking to Andie, I never indicated a love for high torque bite. He has always recommended XR2 in the front for me. Recently, even with slicks, he still suggested staying with XR2 on the front (XR3--even less torque--in the rear). As I mentioned earlier in the thread, the 9668 calipers have a lot of power and I was causing the slicks to howl when really getting on the brakes. For me, I don't want more powerful biting pads than that.

Ultimately, a driver's preference for braking-feel is definitely subjective. So, it's hard for me to say with certainty that someone will love a certain pad torque/bite. But yeah, I think XR2 is an option. And I think you're right in thinking the J-hooks help with bite.

[roastbeef]

andie was very helpful in dissecting what i was describing to him and figuring out what i liked. he helped explain to me how brake bite and torque are two different things, which i found to be very interesting.
one of the things we talked about was how i went from the ferodo dsuno to the 1.11 pads and i was disappointed with the 1.11's. the 1.11's weren't terrible, but they felt like they squeezed the rotors and the UNO's felt like they grabbed the rotors. i like the feel of the initial bite, but the torque is really what i was really after. i don't have a problem triggering abs with these brakes/pads using nitto nt01 tires unless i make a mistake.
the xr1's didn't last me very long, but this was because of a few factors- tracks that are hard on brakes (laguna), tracks that trigger traction control (sonoma/big willow), my heavy car, and me likely braking too much because i'm still progressing and use the brakes too much. other than that, i loved the xr1's.

i wish we could have a track day where different brake companies send out representatives with a variety of pads and we could just have a brake pad test day- where we just take a couple hot laps and then come in an try a different set of pads. that way we could try all the flavors at once. wouldn't that be nice?

[dogbone]

Originally Posted by roastbeef

i wish we could have a track day where different brake companies send out representatives with a variety of pads and we could just have a brake pad test day- where we just take a couple hot laps and then come in an try a different set of pads. that way we could try all the flavors at once. wouldn't that be nice?

Yeah that would be pretty interesting, but I suspect the marketing budget to pull that off would have to be pretty massive if they wanted to do this kind of thing at more than one track..... If there was a bunch of cars, I suspect the logistics of it would be fairly difficult too....

I would think that if you knew a guy with the same calipers or someone using the same pad shape, maybe you could work out buying a half used set from them. Pads are not like tires. In my experience they don’t drop off in the middle of their life. At least, then you wouldn’t be making such a large commitment to try a different pad.

[jritt@essex]

Hello Gents,

I just wanted to say thank you all for your continued support. I really enjoyed reading your detailed feedback dogbone, and I'm glad that the brakes are living up to/exceeding your expectations! Your review validates some of the more intangible benefits that our products provide. As a long-time track enthusiast, I like to say that our ultimate goal is to help our customers have a 'better' day at the track. It's not just about more repeatable braking, lower lap times, and less pad wear. It's also about having more confidence, more fun, and fewer things to worry about while you're out there. It's about not being frustrated pulling pads, not having to bleed between sessions, and not having to worry if you'll be able to get spares or a caliper rebuild when you need them. Those are the points that we sometimes have a tough time expressing, and people don't understand just how much of an impact those items can have on the overall experience during a day at the track. Thank you very much for illustrating the little details so nicely!

If any of you ever have any questions or concerns about anything brake-related, always feel free to reach out to us for assistance. As mentioned in this thread, we are here to stay with our products and support. Thanks again!

[dogbone]

Originally Posted by jritt@essex

Hello Gents,

I just wanted to say thank you all for your continued support. I really enjoyed reading your detailed feedback dogbone, and I'm glad that the brakes are living up to/exceeding your expectations! Your review validates some of the more intangible benefits that our products provide. As a long-time track enthusiast, I like to say that our ultimate goal is to help our customers have a 'better' day at the track. It's not just about more repeatable braking, lower lap times, and less pad wear. It's also about having more confidence, more fun, and fewer things to worry about while you're out there. It's about not being frustrated pulling pads, not having to bleed between sessions, and not having to worry if you'll be able to get spares or a caliper rebuild when you need them. Those are the points that we sometimes have a tough time expressing, and people don't understand just how much of an impact those items can have on the overall experience during a day at the track. Thank you very much for illustrating the little details so nicely!

If any of you ever have any questions or concerns about anything brake-related, always feel free to reach out to us for assistance. As mentioned in this thread, we are here to stay with our products and support. Thanks again!

Hi Jeff.

Thanks for dropping in! Yeah the brakes were great at Buttonwillow. I started slow, seasoning the rotors and bedding the pads. There was a nice pad transfer after the first session. As the day progressed, I was pushing the system harder and harder, braking later and later. Everything felt great. I am eager to drive them again where I can start the day using them confidently and see where I end up! (I'm also seriously considering the rear kit.)

Yesterday I called Essex to give a little feedback after my install. I'll repeat it here:

-the printed install instructions do not tell you which bleed screw to start bleeding first. The instructions mention "inside" and "outside", but there's no easily identified inner or outer screw since they're both on the inside of the 9668 caliper (top and bottom). For anyone who's curious, you start with the lower bleed screw first. Anyway, it would be nice if the instructions had that info.

-I was looking for confirmation about the annulus size for the pads on the rears because the AP Racing tech drawing listed D46, but your site specifically mentions D42. So, I just wanted a clarification that it is in fact D42. (It's D42.)

-It's nice that the Essex website lists out vendor-specific pad shapes for the calipers. However, the ones for Cobalt Friction are either incorrect or missing. So, I wanted to give you guys the Cobalt Friction-specific pad shape info for your website. The 9668 kit uses shape AP19 in either 18mm or 25mm thickness. And the 9449 rears use AP13 in 16.0mm thickness.

Anyway, I'm glad to see you active on the forums. Your posts are always informative. It's another bit of support that is appreciated.

[dogbone]

Well, let's just file this one under----BEEEFY!

The 25mm Cobalt Friction XR2 pads arrived today for the 9668 Radi-Cals. Holy cow! Can you say beefy? (Did you see what I did there?)

Anyway, I have some 18mm XR2's on there now. I'm debating whether I run those out and count the days to compare wear rate to the old kit, or just slam these babies on there and get going.

[warp10]

Originally Posted by dogbone

Well, let's just file this one under----BEEEFY!

The 25mm Cobalt Friction XR2 pads arrived today for the 9668 Radi-Cals. Holy cow! Can you say beefy? (Did you see what I did there?)

Anyway, I have some 18mm XR2's on there now. I'm debating whether I run those out and count the days to compare wear rate to the old kit, or just slam these babies on there and get going.

I had the same reaction to the 25mm pads they are huge! Can't wait to feel the difference of this kit on track. Still can't believe these are 12 lbs lighter than the st60s!

[dogbone]

Originally Posted by warp10

I had the same reaction to the 25mm pads they are huge! Can't wait to feel the difference of this kit on track. Still can't believe these are 12 lbs lighter than the st60s!

Yeah 12 lbs less than the Stoptechs is pretty awesome.

Looking forward to hearing how you like them!

Your new steering wheel setup looks amazing!

[kyippee]

Beautiful meaty pads

[jritt@essex]

Thank you for the additional feedback and recommendations. These are the types of things that help us improve our products and service, and they are much appreciated!

The unfortunate aspect of these types of documentation changes are that they need to be done individually for every related product. In other words, we have to go into every product that uses these calipers and adjust the documentation separately. That means every product listing on the website, and every install manual, which takes a huge amount of time. We are a small company, and we're always strained on the labor hours to do these types of tasks. We try our best, but it's tough sometimes. I will make note of these items though, and we can try to integrate them into future updates. There's always room for improvement!

FYI...The 'inside/outside' reference on the caliper bleeding comes from the traditional, non-Radi-CAL style calipers, which all had an inner and outer bleed screw at the top. The framework for the install manuals was copied over from those, and that language was never changed or updated.

As for pad radial depth, again that's a tough one. Many or most of AP's calipers take pads with different multiple radial depths, depending on the specific caliper variant. In some cases, there are quite a few different variants of each caliper body. Rather than having a separate installation drawing for every single variant of a given caliper body, AP aggregates them all into one drawing. That can make it tough to discern which versions use which accessories, pads, etc. If anyone is ever unsure, they can feel free to contact us to verify. In some cases, AP actually makes special sub-models of calipers just for Essex. If you look in AP's standard listings on their site or print, you won't be able to find all of the AP Racing products we offer. Again, it's always best to check with us and we'll sort you out.

I'll try to grind out the changes to the Cobalt pad shape listings on our site at some point over the next couple of days.

Thanks so much again for your input!

Originally Posted by dogbone

Hi Jeff.

Thanks for dropping in! Yeah the brakes were great at Buttonwillow. I started slow, seasoning the rotors and bedding the pads. There was a nice pad transfer after the first session. As the day progressed, I was pushing the system harder and harder, braking later and later. Everything felt great. I am eager to drive them again where I can start the day using them confidently and see where I end up! (I'm also seriously considering the rear kit.)

Yesterday I called Essex to give a little feedback after my install. I'll repeat it here:

-the printed install instructions do not tell you which bleed screw to start bleeding first. The instructions mention "inside" and "outside", but there's no easily identified inner or outer screw since they're both on the inside of the 9668 caliper (top and bottom). For anyone who's curious, you start with the lower bleed screw first. Anyway, it would be nice if the instructions had that info.

-I was looking for confirmation about the annulus size for the pads on the rears because the AP Racing tech drawing listed D46, but your site specifically mentions D42. So, I just wanted a clarification that it is in fact D42. (It's D42.)

-It's nice that the Essex website lists out vendor-specific pad shapes for the calipers. However, the ones for Cobalt Friction are either incorrect or missing. So, I wanted to give you guys the Cobalt Friction-specific pad shape info for your website. The 9668 kit uses shape AP19 in either 18mm or 25mm thickness. And the 9449 rears use AP13 in 16.0mm thickness.

Anyway, I'm glad to see you active on the forums. Your posts are always informative. It's another bit of support that is appreciated.

[dogbone]

Originally Posted by jritt@essex

FYI...The 'inside/outside' reference on the caliper bleeding comes from the traditional, non-Radi-CAL style calipers, which all had an inner and outer bleed screw at the top. The framework for the install manuals was copied over from those, and that language was never changed or updated.

Yup, I came from the Stillen AP CP5555 setup, so I was familiar with the inside/outside thing. But Top/Bottom---phew!---this is some fancy new tech we're talking about here!

[Chuck's M3]

Originally Posted by dogbone

Yup, I came from the Stillen AP CP5555 setup, so I was familiar with the inside/outside thing. But Top/Bottom---phew!---this is some fancy new tech we're talking about here!

Should remember it as the bottoms up approach.

[inTgr8r]

Originally Posted by mnelson3

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.

On my Z4MC, I had dtc70s and will never go back to them. (on Stoptech)
They were OK on initial bite and modulation but were horrible on pad release when trail braking.
Just as you were feathering off they would grab.

I changed to PCF11s and it was a world of difference.

With my Essex AP kit for the M3 I went with the dsuno (hard to pass up the discount)
It will be interesting to see how they work out.

[mnelson3]

Originally Posted by inTgr8r

On my Z4MC, I had dtc70s and will never go back to them. (on Stoptech)
They were OK on initial bite and modulation but were horrible on pad release when trail braking.
Just as you were feathering off they would grab.

I changed to PCF11s and it was a world of difference.

With my Essex AP kit for the M3 I went with the dsuno (hard to pass up the discount)
It will be interesting to see how they work out.

interesting. my Essex AP kit and CF XR1 pads are in transit.
i can't wait to install and feel the difference.

[PrimeBMW]

Good to see that many of you are starting to see the light with Cobalt Friction.

[dogbone]

Originally Posted by mnelson3

interesting. my Essex AP kit and CF XR1 pads are in transit.
i can't wait to install and feel the difference.

hehe---I have a feeling you will be astonished at the stopping power you'll have at your disposal. And this power and performance characteristic will be repeatable every time you press the brake pedal. Consistency is what reduces lap times. Trusting the brake pedal allows you to concentrate on other things.

I guess this is a good time to reiterate the idea that grippier tires don't just go around corners faster and accelerate faster, they also allow you to brake harder and later. Once you see all this awesome braking power, I'm guessing you'll be itching for stickier tires soon! Oh yeah, the fun never ends!

What tires are you on now?

[mnelson3]

Originally Posted by dogbone

hehe---I have a feeling you will be astonished at the stopping power you'll have at your disposal. And this power and performance characteristic will be repeatable every time you press the brake pedal. Consistency is what reduces lap times. Trusting the brake pedal allows you to concentrate on other things.

I guess this is a good time to reiterate the idea that grippier tires don't just go around corners faster and accelerate faster, they also allow you to brake harder and later. Once you see all this awesome braking power, I'm guessing you'll be itching for stickier tires soon! Oh yeah, the fun never ends!

What tires are you on now?

Hankook TD'S
265 / 295

but i'll will need to go square (9 1/2" wide) on my oem 18".
do i stretch a 265 tire or try to stuff a 285 tire up front?

[dogbone]

Originally Posted by mnelson3

Hankook TD'S
265 / 295

but i'll will need to go square (9 1/2" wide) on my oem 18".
do i stretch a 265 tire or try to stuff a 285 tire up front?

The front suspension really affects how wide the tire can be. I don't recall anyone on stock suspension who runs 285 in the front. What suspension do you have?

I enjoyed the Hankook TD. It has very good braking power. And it corners well.

We've been told that Hankook is no longer making TD's anymore. And no one that I've talked to knows of any successor. Seems odd to just drop a line of tires like that. If Hankook really did drop the TD line, then your next step up would be BFGoodrich R1S. It's faster than TD and can run a full 30 minutes without needing a break. Very nice tire. I find that R1S is the closest thing you can get to slicks without running slicks. If you consider the R1S, just know they run REALLY fat for the listed size. A 285/30/18 R1S runs wider than a 295/30/18 TD or R7.

[dogbone]

A small mod, but one that will get constant use: Convex Rearview Mirror!

As I've been experimenting with video camera placement in the car, the OEM rearview mirror has been blocking the view of the track. This was finally the push I needed to experiment with a convex mirror. Due to the placement of the overhead cage tubes, I knew I couldn't just use a mirror out of the box because I would need to somehow extend the arms holding the mirror.

So, I went to a hardware store and bought a few sturdy metal bars to use as extenders. My goal was to keep the mirror as high as possible, and as far forward as I could. I think I fashioned something simple that will work. It feels sturdy when I pull on it with a fair amount of effort. Hopefully I can get out there soon and try it out.

Now, I'm wondering if I can get that black stuff off the windshield that was behind the OEM mirror. Anyone ever try razor-blading that off? Or have any better ideas?









Here's the latest look of the car at Buttonwillow in January (before convex mirror). (Thank you SpeedDistrict for including the track photos [and transponders] in the signup fee!) Anyway, there must be a new dude working for CaliPhotoVideo or something because, while the recent photos are nice, this latest photographer is pretty daring (or crazy). He stands in places I just would not stand. Look at the last photo. If it looks like he's close to the car, IT'S BECAUSE HE IS! He's standing on the inside of the apex at the top of Cotton Corners just a couple feet from the berm! He's so close sometimes, it's actually distracting to the driver. To be honest, I can't believe he's allowed to stand in some of the places he's standing. He's taken the danger factor to a whole new level. Sometimes, he stands in spots where, if you flew off the track in a corner, he would be right in the hot zone. On this most recent trip, while sitting at the Start/Finish line, I did hear on the track radio that they were moving him from some spot because it wasn't safe.....I love a good track picture, but it's not worth risking your personal safety.

[roastbeef]

Were the trackspec vents of any noticeable benefit in heat management or feel?

[dogbone]

Originally Posted by roastbeef

Were the trackspec vents of any noticeable benefit in heat management or feel?

The car "feels" very good. I am happy with it's handling characteristics. I keep experimenting with the wing angle. That experimentation will need to continue. I just need to drive the car more to understand it's current state better. And, as always, I need to continue growing as a driver. In particular, I believe I need to trust the brakes more and brake later and more assertively and brake less. And I'm not talking about these particular new AP brakes; I'm just talking about braking in general. I tend to hedge my bets and brake just a tad early and a bit too much. I don't think I'm taking full advantage of the car's lightness and the braking power of the Pirelli DH's, so it's something I want to improve on. (In fairness, I don't think my braking is terrible, but I can do better.)

As far as heat goes, I have begun analyzing data from the AIM from the one Buttonwillow day I have so far. To make any meaningful comparisons, several factors have to be considered. Two big ones are ambient air temps and tires. Because I'm on Pirelli DH these days, it muddies the waters a bit because I've only been on them since the second half of 2017, but I was on Yoko slicks early last year so that's pretty similar. The temps from two weeks ago were virtually identical to temps a year ago, so that's good.

What I'm seeing so far is that the oil and water still heat up about the same on a hot lap as they did a year ago. But the water and oil do seem to cool a bit more on cool down laps---about 5-10ºF more cooling on the oil on a cool down lap. I will need more track days get more data.