911 GT3 Brake Ducts on E92 M3

[Redd]

Did some enhancements to the old brake ducts. Here are the new templates for the brake ducts. White dots are where holes should be drilled for the cable ties.

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This is a pic of the brake duct on the 997 Turbo, showing the cutout on the inner radius of the brake shield.

[0-60Motorsports]

Nicely done. Awesome bang for the buck mod

[beats]

I just ordered a set. Will report back once they have been through a track day or two...

[vincE92M3]

Nice work!

[The HACK]

Blowing air directly onto the rotor does little to control brake rotor temperature, blowing air into the central hub does most of the work, because vented rotors cool by sucking air in through the center of the hub and blowing it out of the vanes through the spinning action of the rotor. Cutting the shield is unnecessary, that's why you see most of the racing brake duct design that replaces the dust shied redirect the majority of the cool ambient air to the center of the rotor, not the rotor surface.

[doogee]

Originally Posted by The HACK

Blowing air directly onto the rotor does little to control brake rotor temperature, blowing air into the central hub does most of the work, because vented rotors cool by sucking air in through the center of the hub and blowing it out of the vanes through the spinning action of the rotor. Cutting the shield is unnecessary, that's why you see most of the racing brake duct design that replaces the dust shied redirect the majority of the cool ambient air to the center of the rotor, not the rotor surface.

This is correct. These will have little to no effect.

[Richbot]

Originally Posted by doogee

This is correct. These will have little to no effect.

snort

explain every brake duct on almost every BMW ever made

[Redd]

If they're mounted in that fashion on the 997 GT3, they can't possibly be worthless. Maybe cutting the shield was excessive, but can't hurt to get more air to the disc.

[Redd]

Ok final iteration going in.

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This is what they look like mounted.

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Left:




Picture taken from the angle of the duct, showing where the airflow will go:


That's it! Trackday next week, will report more after that.

Redd

[Redd]

Trackday over and the ducts performed admirably! Stayed attached after several 200+kph runs down the front straight of Sepang F1 Circuit.

They also helped a lot in preventing fade. I usually start to experience brake fade after the 3rd session, but I ran 5 sessions today and no fade. Would love to hear from the other trackies if they have pyro data on these ducts.

I'm gonna call this one a success.

[ayao]

Is there any easy way to share a "template" of some sort that I can use to trim the ones I picked up? What did you end up using to cut the plastic?

Originally Posted by Redd

Ok final iteration going in.

Right:


Left:


Redd

[Redd]

Originally Posted by ayao

Is there any easy way to share a "template" of some sort that I can use to trim the ones I picked up? What did you end up using to cut the plastic?

To be honest I just used the pictures as a guide when doing extra sets. Just use the markings as reference points and cut away. All I used were a sharp pair of sharp scissors for 90% of the cutting and rounding the corners. Also used an exacto knife to cut one of the portions that I couldn't get to with the scissors.

[bigjae1976]

I would never imagine a Porsche part being $7.50 but it looks intriguing!

[Richbot]

Originally Posted by bigjae1976

I would never imagine a Porsche part being $7.50 but it looks intriguing!

you can add a porsche crest for $500, and have them painted in body color for $950 (must also select Sport Chrono; total vehicle price increase of $3,900)

[ayao]

Originally Posted by Richbot

you can add a porsche crest for $500, and have them painted in body color for $950 (must also select Sport Chrono; total vehicle price increase of $3,900)

Don't forget badge delete.

[marconi118]

Here in europe I bought the 99734148392 and 99734748492 fot 1.87€ excl VAT piece

[aus]

Why can't BMW do this for the /M cars?? Especially up front. They make all kinds of plastic that shatters after 4-5 years. At least make it useful.
.

[Redd]

Long term report - After 3 trackdays, daily driving and several long distance trips driving up to 200kph, these brake ducts have remained in place.

[aus]

Originally Posted by Richbot

I could be taking crazy pills because it's been like 40,000 miles since my Stoptech kit went in, but IIRC our stock shields are also pretty open around the inner radius of the shield to let air get to the annulus of the friction ring. I'm just leery of letting the lower ball joints and aluminum upright/suspension arms see the radiant heat from a brake, but it's probably fine. You could also probably just cut a little triangle out, or a couple of slots on the inner radius of the shield, and keep most of the shield intact for the other benefits. But for maximum attack what Redd did is probably the best bet

EDIT, yarp, big ol' air gaps, just not open right where the the duct throws the air:

My plan to test is simply to only install one and do a mini brake-bedding procedure and see if there's any difference on the hat, rotor face, caliper and/or wheel temperature left to right, then install the other one and see if the temps even out. I have an IR and a probe pyro. I'll do this without any mods to the heat shield because I'm lazy first

But keep in mind I'm usually all talk and I don't need to be under the car anytime soon, soooo, hopefully somebody else with a pyrometer can beat me to it for science

I'm extremely glad this thread exists. I had no idea these were $8 *per pair* the cheapest I had found was like $25 each, and not as good a fit

Just wondering if you ever did this experiment side to side??
.

[s0ldats]

^^ would love to see if any of that data was collected too

[Signature Wheel BMW]

Originally Posted by s0ldats

^^ would love to see if any of that data was collected too

Bunch of M2 guys have done this, great results on the track. If it works for Porsche, you know it'll work. Porsche engineers don't add weight to the car unless it's functional. Hell, the GT3 RS don't even have real door handles and the Porsche crest is a decal instead of a 1oz badge.

OP: You do not want to cut the shields. The idea of these ducts are to bring fresh air to the central hub, at high speed the air will make its way to the hub area (fluid dynamic engineers can better explain this). The rotor is a fan that draws air from the hub to cool BOTH sides of the rotors. The shield channels the fresh air to the hub area, purposely blocking the rotor. Blowing fresh air directly at one side of the rotor disrupts this "fan movement" and uneven cooling of one side of the rotor. See below what a true duct is supposed to bring air to. What this means is most of the aftermarket brake duct shield adapters out there are flawed if it just hits the one side of the rotor surface.

M2 DIY, so don't follow it for our cars, just use as a reference: https://www.youtube.com/watch?time_c...ature=emb_logo

[Bartledoo]

wouldn't these have worked much better if attached to the tension arm?