Black & Tan 332iT

[Albino09]

I've always liked the look of the CSL rep bumper without an intake duct. These would nicely complement the deletion of the factory brake ducts.

[YoitsTmac]

Very impressive. I like the thoroughness of your tests. Keep up the great work!

[Bry5on]

Well today I was home sick with a cold, so in between meetings I installed v2 of the scoop duct and did some highly scientific testing. This version has some tweaks to make it print better, and to clear the tie rod boot and tie rod itself at full lock in either direction. In the process of this I also eliminated the shroud on top, which means this duct is now compatible with the OEM brake ducts (I tested the flow outlet location using the method I'll outline below).

First off, here's clearance at full lock in either direction. It's extremely close duct-duct in one direction, and duct-tie rod boot in the other direction. I wanted to maximize function, so I set these to be super close.
Full lock left (view from front of car looking back):

Full lock right (view from top down, showing the tightest clearance which is duct-duct):


Here's what it looks like when you're driving straight ahead, again from the front of the car looking back:

https://youtu.be/oP8onVb59pE

No problems there, everything looked good, so I moved on to validation testing. I tested two configurations: one where the air/water deflector attached to the pork chop is in place, and one where it was folded back, out of the way. I chose these two as the lower edge of that deflector and my scoop are both between 85-90mm off the ground, meaning there would be a good chance this deflector would prevent the duct from functioning.

The test setup was an electric leaf blower and some yarn telltales:




I did a round of testing with the wheel locked full left so I could witness the telltales, then repeated the two tests with the wheels straight ahead so I could see the telltale on the outer rim of the rotor (spoiler, it moved!) and through the wheel barrel/rotor. Here are the results:

https://youtu.be/8Zhji8t9YA8

So we learned that yes, the water/air deflector does prevent the duct from functioning correctly (at least the under-car scoop function), and we also learned that once that's out of the way it effectively moves an incredible amount of air through the rotors. I put a telltale on the outlet vein of the rotor, *away* from the highest pressure source, and the telltale moved when positioned at the vein, and also when I draped it over the 'Swiss cheese' holes in the CSL rotor. This was also confirmed by simply placing my hand outside of the spokes of the wheel and feeling the air rushing out (some of this was likely bypassing the duct I'm sure).

So following that testing, I trimmed the water/air deflector back on the inner edge to expose a nice clean air path to the duct.
Before:

After:


Next up will be some controlled speed/hill descent braking tests followed by IR temp sensor readings of the left and right rotors, as I didn't install a duct on the passenger side so I could get a proper A/B test. Stay tuned.

[Bry5on]

Is this effectively an air scoop grabbing from the bottom of the wheel well? I can kind of make out the rough shape of the tire and the control arm but having trouble figuring out my xyz reference.

Precisely. Test fit yielded a few tweaks for clearance at full lock. Otherwise it’s looking good.

[Albino09]

Is this effectively an air scoop grabbing from the bottom of the wheel well? I can kind of make out the rough shape of the tire and the control arm but having trouble figuring out my xyz reference.

[0-60motorsports]

This will fit all M3s, and will provide effective brake cooling for a car with a CSL bumper especially. It's also designed to clear 17" wheels and the highest possible wheel offsets that won't hit the strut. Bigger wheels will just have more clearance.

Thats awesome! Looking forward to it. I would love to return brake cooling to my CSL Bumpered M3 again.

[Bry5on]

Oh Will this fit cars with OE CSL intake setup and CSL bumper?

This will fit all M3s, and will provide effective brake cooling for a car with a CSL bumper especially. It's also designed to clear 17" wheels and the highest possible wheel offsets that won't hit the strut. Bigger wheels will just have more clearance.

[0-60motorsports]

More rainy day projects, I started working on a brake duct that'll be much much better than the one I removed to install the CSL intake duct. Here's a first draft in CAD, and tomorrow afternoon I should have the prototype all printed up.

https://www.youtube.com/watch?v=m5zYhd987Ds

Oh Will this fit cars with OE CSL intake setup and CSL bumper?

[Bry5on]

More rainy day projects, I started working on a brake duct that'll be much much better than the one I removed to install the CSL intake duct. Here's a first draft in CAD, and tomorrow afternoon I should have the prototype all printed up.

https://www.youtube.com/watch?v=m5zYhd987Ds

[kaiv]

Progress continues..


After that insert as practice, I turned to the real project. A ZHP bumper brake duct to CSL airbox inlet duct and accordion flex boot. First I masked off the area to get some good measurements and a 3D scan with the iPhone faceid lidar sensor, which gave me the local area and surfaces I needed to route a duct:


Then off to the 3D printer for a first iteration. I used the entire build height of the printer, and actually needed a few mm more, so I nipped the top 5mm off of the printed part of the duct. You'll see below why this didn't really matter after installing the TPU printed flexible accordion boot. This is actually version 2:



It helped having an extra CSL flap to get dimensions, as this is an odd shape:


And after adding some mounting points to V3, we're in business. This piece uses two factory mounting points to secure in place along with the bumper opening to locate itself in 3D space. From there, the CSL airbox is installed from the top just as it is on the factory CSL. The flexible TPU piece in between has a groove that locks into the CSL flap just like stock, and is flexible enough to snap/pop in place on install. It also has double walls to locate on the duct itself to make sure it stays positioned, even as the engine vibrates at high revs. So, here it is:



You can see here how the flexible boot fully encompasses the section of print I had to notch out:

Incredible work Bryson! Can't wait to get mine! 😄

[Bry5on]

Well well well, it appears those BMW engineers really were on to something with that flap ducting.

Background: I have both the pre-and post-flap ducting connected (ie: with the flap closed I'm drawing air from behind the left side of the bumper, but not with any sort of ram effect). You can see the termination of the post-flap intake duct in some of the photos above.

Tonight, on my drive home, I datalogged at a reasonably constant speed and rpm (~3500rpm, 5th gear, ~65mph) a drive with the flap open (briefly), then closed, then open again. At this constant speed and engine load, I saw an 8*C (14*F) in 1 minute, 15 seconds, with most of the drop happening in the first 15-20 seconds. This is a rather impactful change! Definitely more than I expected, as I already had a low temperature air source and I didn't see this behavior before doing the duct.

In the stock CSL firmware in sport mode the flap opens at 3300rpm in gears 1, 2, 3 (41mph) and at 40mph in gears 4, 5, 6. Seems logical.

Vertical yellow bars in the datalog below are when the flap opened/closed.

[Will]

Amazing work! Thanks for documenting and sharing with us.

[Projecte46m3]

Doing god's work in here!!

[Bry5on]

Progress continues..

First, I picked up the isofix cover that I had retrimmed in some e46 natural brown leather that heinzboehmer and I came across a few months back, finally:


Up next, we move back to 3D printing. I managed to fit the bigger screen into the ash tray dimensions, as above, and added some USB-C CarPlay and charge ports while I was at it. I tried to capture a bunch of photos to give a sense of the lighting match. It's actually pretty damn good, but the camera really struggles to capture it the same way as your eyes.

Open:

Closed:





After that insert as practice, I turned to the real project. A ZHP bumper brake duct to CSL airbox inlet duct and accordion flex boot. First I masked off the area to get some good measurements and a 3D scan with the iPhone faceid lidar sensor, which gave me the local area and surfaces I needed to route a duct:


Then off to the 3D printer for a first iteration. I used the entire build height of the printer, and actually needed a few mm more, so I nipped the top 5mm off of the printed part of the duct. You'll see below why this didn't really matter after installing the TPU printed flexible accordion boot. This is actually version 2:



It helped having an extra CSL flap to get dimensions, as this is an odd shape:


And after adding some mounting points to V3, we're in business. This piece uses two factory mounting points to secure in place along with the bumper opening to locate itself in 3D space. From there, the CSL airbox is installed from the top just as it is on the factory CSL. The flexible TPU piece in between has a groove that locks into the CSL flap just like stock, and is flexible enough to snap/pop in place on install. It also has double walls to locate on the duct itself to make sure it stays positioned, even as the engine vibrates at high revs. So, here it is:



You can see here how the flexible boot fully encompasses the section of print I had to notch out:


And lastly, a bit less exciting, the bracket for the PDC and trailer modules showed up from Europe, so I dropped that in:


All in all, a solid update I think.

[Bry5on]

So I recently bought a 3D printer and I’ve been practicing by making smaller things to learn the ropes before I jump into printing the ZHP-CSL duct and isolator boot.

So far I’ve experimented with TPA, ASA and ABS. I expect ABS will be my most popular material, and to that end, here’s an ash tray insert that I designed to hold a smaller 1.54” screen, along with gauge.s circuit board and GPS receiver. A print just finished for the bigger screen version (which clears to the half millimeter basically everywhere) that might replace this one, but here’s how it looks so far:



Here’s the big one: