heinzboehmer's 2002 Topaz 6MT Coupe

[heinzboehmer]

Holy crap, I've got this same noise and couldn't figure out where it was coming from, lol. This has to be it.

I forget, are you on stock headers/section 1? It's nowhere nearly as pronounced with those as it is with the supersprint stuff, but the transmission brace should still make a difference. Wonder why BMW included it on the non-Ms but not on the M3...

Hell yeah on the scoop test! If you’re going to modify, you should tweak the brake shield side as that little corner at the top of the main duct really is there to straighten the flow out as much as possible. If you do decide to bring it inward, you might consider adding some vanes to help the flow follow the curve and arrive basically straight into the brake shield duct. The main duct is there to direct the flow and the little duct is there to contain/compress/guide it into the rotor center.

That makes sense. Was trying to avoid reprinting those so I didn't have to dip into my stash of PET CF, but seems worth it. Will probably start by trimming the existing ones and then decide if I want to tweak and reprint.

[Bry5on]

Hell yeah on the scoop test! If you’re going to modify, you should tweak the brake shield side as that little corner at the top of the main duct really is there to straighten the flow out as much as possible. If you do decide to bring it inward, you might consider adding some vanes to help the flow follow the curve and arrive basically straight into the brake shield duct. The main duct is there to direct the flow and the little duct is there to contain/compress/guide it into the rotor center.

[oceansize]

Couple of updates.

First up, the transmission exhaust brace is great. Greatly dampens the tinny, high frequency vibrations at about 2.5-2.7k rpm. They're not eliminated, but rather the brace seems to shift their frequency down quite a bit. It's no longer a rattly metallic noise and is now more reminiscent of the typical low frequency engine NVH present in most ICE cars.

Holy crap, I've got this same noise and couldn't figure out where it was coming from, lol. This has to be it.

[heinzboehmer]

Couple of updates.

First up, the transmission exhaust brace is great. Greatly dampens the tinny, high frequency vibrations at about 2.5-2.7k rpm. They're not eliminated, but rather the brace seems to shift their frequency down quite a bit. It's no longer a rattly metallic noise and is now more reminiscent of the typical low frequency engine NVH present in most ICE cars.

And now onto track stuff. Shockingly, PET CF did not survive being in direct contact with the caliper at a brake heavy track. I didn't even bother mounting the duct after seeing how distorted the small mounting tab was getting. Unfortunately, I stepped on the piece and broke it when installing all the street stuff back on the car, but you can kinda still see the distortion:



Tried to make it more obvious with some highlighting. Most obvious issues are how much the "legs" started to pull up away from the rotor face (red) and how much the mounting tab that the caliper pin goes through bent back (green):



Also, early in the day, I took a line through the corkscrew that was way too far left and ended up basically jumping the car off the top. Full droop + slight right turn of the front wheels resulted in the mounting features (and some others) getting crunched off the control arm part of the left brake scoop:



Picture from Bryson's car to show how it's supposed to look:



Tightened up the zip ties and got through the day without much issue. Gonna need to print a new scoop though:



I'll likely try to fix this slight contact between the two scoop parts before reprinting. Seems like bringing the outer edge in a bit will do it.

Good news is that the dust shield part of the scoop held up perfectly. I printed that one out of PET CF for the thermal properties and it still looks just like it did when it came out of the printer.

But all in all, the scoops worked great! Had zero fade issues, did not find any newly failed dust boots and the pads look almost exactly the same as they did before the track day. I completely forgot to take measurements before, but they're currently at 13 mm thickness (including backing plate which is about 5 mm). Product name (0776.08.17.44) says they're 17 mm thick with backing pad, so there's still about 2/3 left after 3 days (~8 hours) of track time. Not bad.

Also, I did say I would be taking brake temp measurements to have some data, but for some reason the turn 10 paddock entry was closed. This meant that the brakes had cooled significantly by the time I was back in the paddock and any data would have been meaningless. I think I'll try to make the next track day a real science day. Will swap in new dust boots, install the tweaked scoops and take temp measurements throughout the day.

[heinzboehmer]

Oh also gonna be at Laguna Seca this weekend, so I'll finally be able to test the 996 caliper evacuation ducts

I don't fully trust the material yet, so won't be running them with the fan. Plan is to just run the small mounting tab for a couple sessions and if thay doesn't distort/melt, then mount the full duct on (sans fan). I've only printed a duct for the one side, so I'll take temp measurements. I don't expect to see any difference, but why not.