Another brake duct cooling thread (lite)

[Car54]

FWIW...3 days at VIR, 1 day was just open lapping and I didn't wear through more than a 1/3 worth of PFC01. I wore through more at one day at Sebring than I did 3 days at VIR. Never did my brakes give me any trouble, they boiled and smoked, and popped center caps off at Sebring. I'd say for the $300 I have into it...I'm happy with how things worked out. YMMV

[Porschefile]

Cool, glad it worked for you. Maybe I should do the same thing, just for pad wear. I have an open hole now (duct taped over) where my hosing used to run through to the rotor. The hose won't fit with my wider front tires and lowered suspension.

[Richbot]

Good news! Did you get any pyrometer data?

[Richbot]

Originally Posted by TXmtrhed

It will be interesting to see if the new M3 has brake ducts as does the new F30 because it appears that it will use the air curtain slots (not seen on the F30).

The vanilla F30's have air curtain slots too, they're just tough to see. Take a close look at the leading edge of the fender liner, they're there, inlets are just outboard of the foglamps

[Car54]

Originally Posted by Richbot

Good news! Did you get any pyrometer data?

No real data. Once I go back to Sebring it will be a better test...I have an IR gun, but I think it's limited to 500°.

[LiM3y]

Sweet! I held back after the derision expressed on the board, but it appears to work!

[apecush]

I'm thinking the hole in the fender method will be fairly effective at moving more air toward the rotor. If you look at the backing plate, it is angled away from the rotor toward the front of the car - the only explaination for this is that it scoops air toward the centre of the rotor. An increase in airflow to the wheel well would increase air directed toward the rotor. I've had other performance cars where the backing plate hugs the rotor pretty close - the M3 backing plate design is quite different.

With respect to the stock brakes, they are quite capable with upgraded pads on street tires. While I'm by no means a good driver, I just finished a track day at the track the local indy race was run on. 3.6 km with several locations braking from above 120 mph, two of which were into hairpin turns. Brakes did not overheat, boil the fluid, or burn the pads in repeated 25 minute sessions. An instructor that rode with me in one of the sessions commented that the brakes were very good.

On semi-race and race tires (sub-100 treadwear), I can see the additional load over-taxing the stock set-up though.

[adc]

Originally Posted by Richbot

Pads/fluid and a little air are probably all the car needs until you're serious about doing repeatable lap times and at that point it's smarter to get something that doesn't have a trunk or a roof or windows any of that other useless crap on it.

After 2 hot days at VIR, I tend to agree.

I made my "firehose" (meaning non-directed) cooling ducts awhile ago and found them satisfactory for Shenandoah, and maybe ok at Summit Main.

At VIR, using 265/285 RS-3's and RS-19 pads with (maybe not so fresh) Super Blue, I had to start managing the brakes as soon as I picked up some speed. If I was full on the gas and started my braking around the 1-1.5 marker on the back straight (and similarly on the front straight), it would work for only 2 laps, after which I started losing brake capacity. Heck for one glorious lap I even braked after the 1 marker - but it just wasn't consistent.

At the same time, at least to my non-trained foot it didn't seem that the mismatch was huge - so maybe a small improvement can tilt it the other way.
Of course there are other potential factors at play - driver, braking style, fluid etc.

OEM backing plate scoops look like they might help too - but I wonder if their diameter is too small for the M3...

There's one more idea - to emulate the GT3's directional scoops which are attached to the lower control arm - I saw a few Boxsters at VIR which had these plastic scoops. I'm thinking I might try my hand at a bit of aluminum or plastic manufacturing...


I mean, I'm not sure I want to invest 10% of the car's value into a BBK, or trade the M for a Porsche which would put me in the hole far worse. As long as these small projects remain small and not too challenging, I'll keep doing them.

[Car54]

Here's another view of where the openings line up with respect to the wheels. These are 275/30/19 tires.

[MKE_M3]

Originally Posted by Car54

Here's another view of where the openings line up with respect to the wheels. These are 275/30/19 tires.

Looks nice.