[RbBugBitMe]

I've uploaded a screen grab of the topology optimization process for the rotor hat with is pretty cool to see.

I've hooked up with Link Engineering in MI to quote brake dynomometer testing on the topology optimized rotor hat. We're trying to decide what SAE test to run but we've pretty much narrowed it down to one and then I'm likely modifying it to be more harsh for a racing environment.

The standard test has a bunch of block cycles that include a few hundred 80-3km/h stops at 0.31g, ten 100-3km/h stops at 1g, and ten 80% of Vmax-3km/h stops at 1g. I will likely push up that 1g requirement to 1.3-1.5 to make it more representative of the data set below and I need to figure out what Vmax is going to be.

I put feelers out for some legit track data from guys that can achieve 2g deceleration and immediately had volunteers so I'm evaluating that data right now. I could provide that data to Link to feed it into the brake dyno and exactly replicate on track performance as an additional block cycle. I just need to see how much customization of this testing adds to the quote. Unfortunately from the volunteers I've had so far none are logging brake pressure which would be really nice to have. Ultimately I'd like to estimate a few parameters and calculate the rotor torque over the whole braking event and feed that into the FEA.


I'm excited for this testing because it will put the Wilwood calipers and pads as well as my topology optimized caliper bracket through the same torture test.

I've got about ten RFQs out to make the rotor hats while the rotors sit in my office looking all sad.

Finally, I now have everything (brake line adapter too) needed to install the caliper kit on the M sport rotors. I should be posting videos of the install and driving shortly.

[RbBugBitMe]

Brake dynos!

I've had a few phone calls with testing facilities and it looks like I'm going to be moving forward with some sort of brake dyno testing. I don't know exactly what because I have to specify what I want to do. I was hoping there would be more organization in the industry given the safety implications but it all seems to be company and use case specific.

Thats good and bad for me. I don't have an SAE spec to say here quote this test and hand over parts to beat the hell out of. But, I get to come up with anything I want. So I could say run two full races around Martinsville or 2 years worth of track data at Road Atlanta plus 10 emergency stops. Whatever I want.

So I need to decide how I'm going to handle this. Testing to ultimate failure and validating my FEA is very different in terms of time and $$$ than a durability test looking at 10,000 cycles. I'm also likely going to plan around rotor failure. Running one Martinsville race will junk a rotor ring and pad but I want the rotor hat to live on. So how many rotor rings can the hat outlive? Is that even relevant testing for how these rotor hats will be used?

Gonna be a fun summer! If you want to keep track of it all I'm back to vlogging and uploaded my latest video.

[RbBugBitMe]

Finally the install begins!! Here's a quick video of why I'm using Wilwood parts.

https://www.instagram.com/reel/CpHfB...d=YmMyMTA2M2Y=

https://www.instagram.com/reel/CpHZH...d=YmMyMTA2M2Y=

[RbBugBitMe]

For some reason the caliper weight has been very hard to find online so here it is with search terms
F30 4 piston brembo caliper weight is 10.5lbs

[RbBugBitMe]

I'm starting to fill in some holes in my data to better compare systems and adjust the direction I want to go with the final kit. Ultimately I want something that would be a better replacement than a full M Performance kit at a similar price. Based on what I'm seeing right now its looking like I should make some changes.

For the front the plan was FNSL6R calipers which was purely for fitment purposes though I think I was overly aggressive and wider FSL6R calipers will work. The benefit here is 20.3 mm pad depth vs 16.5mm at almost no cost difference.

If I go with a 355.6mm (14in) rotor I'll shed 18.45lbs off the front axle unsprung mass compared to the M Perf and still shed 10lbs compared to my current 340mm M Sport setup. If I go with a 381mm (15in) rotor I'll still save 10lbs off the front M Performance unsprung mass and have a larger diameter and thicker rotor.

If I go with 355.6 in the front then I'd probably change up plans and go with the 330.2x25.4 rear rotor. I don't have rear caliper weights yet but the rotors alone are 5.4mm thicker and 12% lighter.

If I go with the 381mm front rotor then I'd go with the 355.6 rear rotor but this could be a struggle to get heat into and working right. Its 10mm larger and 7.75mm thicker and quite a bit heavier. Its just not an appropriate rotor for the rear. Plus the optimized rotor hat will be like swiss cheese and probably improve cooling.

So for the near future where I'm 99% street driven, I think a 355.6mm front and 330.2mm rear setup is ideal. The real bad ass part of this kit is that if I wanted to go to the track and swap all my rotors to larger ones, the rings will slide right onto the same rotor hats and the caliper brackets will just need different spacers slid onto the studs. I could even daily with 330mm or 345mm rear OE rotors to save maintenance costs. This is turning out to be way more flexible than I imagined.

[FaRKle!]

How's the clearance difference between MPerf/MSport 370mm setup and PdV 380mm? Is there not a 370mm option for the PdV kit?

[RbBugBitMe]

Wilwood works in inches and doesn't have any rotors between 14" and 15" with the lug drive I'm designing around. But its possible the clearance is the same...

The Wilwoods have a lower profile than the Brembo cast caliper and pad. Its hard to judge in the pic but I'm measuring somewhere around 0.5" extra radial clearance when you align the pad cross pins which may not be the right thing to align.

I also have CAD models of the Stoptech and Dinan Brembo 380mm kits for the F30. You can see my rough outline of the Wilwood caliper is about 0.4" radially inside the Dinan clearance template at the rotor centerline but are quite close at the corner near the spokes. Does the Dinan 380 kit bolt onto 18" BMW wheels? I don't know, I'm sure someone here does.

[SGoodman23]

New to the forums but have had my F30 for about 6 years now so starting to think about brakes.

Very interesting and ambitious project, especially since you're balancing a day job. Just curious to see when you think you might have something commercially available in terms of the caliper set or are you waiting on R&D on the floating rotors so that you can release both the caliper set and floating rotor set together.

[RbBugBitMe]

Ideally calipers only in the next 1-2 months and rotors shortly after that.

Small but exciting update. The optimized rotors are real and on the way.

[RbBugBitMe]

These beauties showed up today and I am so damn excited this long term project ended up taking me this direction. The assembly is actually lighter than I was predicting in CAD.

This is a list of rotor weights as well as my rotor weight and some CAD predicted weights to illustrate the differences a bit more.
OEM 340x30 = 22lbs
PdV 340x30 (theoretical) - 18.3lbs
PdV 355x31.75 - 20.0
OEM 370x30 = 26lbs
Stoptech 370x30 - 24lbs
Paragon 2 piece 370x30 - 23.4lbs
PdV 370x30 (theoretical) - 21.7lbs
Paragon 2 piece 380x30 - 24.1lbs
PdV 381x31.75 - 24.7lbs

So going from my grey 340mm Msport calipers that are 4lbs heavier than the forged Wilwood caliper/pads/bracket I'm saving 6lbs of unsprung weight and 2lbs of rotating weight per corner to gain a larger OD and thicker rotor ring with more thermal mass concentrated in the ring which should make these quite a bit better at running hard on track. I'm not going to bother with CFD but I assume air flow will be better through my rotor vanes paired with these swiss cheese rotors.

Compared to the 370x30 OEM rotors I believe I'll still see temp and brake fade improvements due to the mass in this heavy and thicker ring. Weight savings also get up to 8-10lbs per corner.

Also, I've only confirmed one model so far but I heard Wilwood and AP Racing share caliper mount spacing dimensions. Exciting but needs more research.






These were made by a new (to me) shop and generally it's looking good dimensionally but the finish sucks. Sliced my finger within a couple minutes of holding it. I'm probably going to go buy a harbor freight tumbler tomorrow to deburr and polish them before anodizing. I'll then bring them up to my day-job when I go on the 19th and put them on the CMM and hardness tester before installation.

[RbBugBitMe]

Not sure why this was hard to find online. Measured the Brembo caliper bleeder screw size. M10x1-15

[RbBugBitMe]

So I received the first two rotor hats last month and made my way up to my day-job inspection lab to find some painful issues. The main one being the incorrect dimension to position the retaining ring so it would not fully install with the rotor installed. Ultimately I am going to get the bits modified by a buddy so they do work but the shop made a new set for free to correct their errors.

They arrived while I was out of town and everything seems to fit well but I still need to tumble them, file some tight corners and update the drawing, do some additional inspection, and anodize them before I do any test driving.

While all of that is going on I can focus on getting the Wilwood calipers installed on the OEM rotors. The car was under the knife for a long time so I needed to put some miles on it before testing the caliper kit.