Can we talk about brake cooling?

[Slideways]

A friend of mine who was a race engineer for many years said brake cooling is something people often overlook, and it might be one of the most important factors. Even the biggest most badass rotors/calipers eventually soak with heat and if it cannot be expelled, you're at the limit. I wonder how stock brakes with good pads and all the cooling would perform on our cars compared to a BBK with no added ducting.

According to George Hill, stock brakes with pads and a few upgrades can be made to work on track. I believe he runs stock brakes on his S54 track wagon. Not sure what the wagon weighs though.

[eacmen]

According to George Hill, stock brakes with pads and a few upgrades can be made to work on track. I believe he runs stock brakes on his S54 track wagon. Not sure what the wagon weighs though.

Agree with this 100 percent. Stock brakes with good cooling, SS lines, good fluid and good pads is going to perform great. The reason I went to BBK was quick pad changes and there was one event where the slide pin fell out of my front caliper. Likely my fault for getting grease on the threads and not cleaning it off well enough. But after that the fixed caliper design really appealed to me.

[George Hill]

Whats that phrase... "without data you are only assuming" or something like that.

I've had more than a few smarter and more experienced track guys (and I don't me DE guys, I mean pro level) tell me for an HPDE most can get away with stock brake calipers. The general consensus was to run it and if I observe an issue then start investigating.

My wagon with me in it is 32-3250 and a full tank of fuel, I ran E46 330 calipers/rotors with DTC60s, random rotor "blanks" no dust shields, no ducting, rubber guides and Castrol SRF for years. That's maybe 30+ track days plus street driving and only had one cracked rotor. The car will do 140mph at CoTA and I've never had any brake fade issues. *For most of that time I was running 330 rear brakes with no dust shields and DTC60s, 2023 I think it was I switched to rear brakes and rotors (literal same pads as before), no change though.

Last summer I swapped to M3 front suspension allowing me to run M3 calipers and rotors (no dust shields) and then I went to RaceMagic pads and the difference in brake operation was night and day IMO. *I think I am going to have to move to solid guides, not thrilled about that, but something I will be keeping an eye on. Otherwise I still haven't seen an issue with the brakes over heating but I can tell I am getting more heat in them now as I can "use" them at more points on track. Next summer I will keep an eye on it though and do some testing to make sure I am still good.

There have been a number of WRL endurance teams running stock M3 brakes for 8hr enduros. I think most have switched for reasons outside of "brake cooling" benefits alone.

[bigjae46]

The stock brakes working depends on your definition. On my E90 M3, the stock brakes with track pads work. You can smoke the pads in a weekend...quite easily. So they will slow and stop the car until they don't. Then driving skill will have a massive impact on what works. At least in an E46, a lower skill driver will typically be much harder on the brakes. I view this as a performance and economic decision.

I run a 4 wheel Stoptech BBK simply for cost reasons. Pads last 2x longer and the rotors easily last 5x longer. Calipers haven't been rebuilt - all of the dust boots are still pliable. My overall brake costs have been much lower over 13 years of ownership vs running stock brakes. You also have to consider the economics of losing track time due to brake issues.

Brakes can have a significant performance benefit, mostly in feel and consistency. I prefer the initial softer feel of the BBK vs the on-off stock brakes. Most like the immediate or sudden bite, I'd rather have the brakes a little dead which makes braking much more controllable. Much easier being smooth coming off the brakes.

But...decent brake cooling on stock brakes will work well. I've considered going back to stock or a smaller BBK for weight savings.

Vorshlag makes some deflectors for an E46 which look interesting. I would like to do some testing to see if they work. A spring project...

[JakeM346]

Best thing I know (also cheap) is using the 997 Brake air deflectors. The’re mounted to the 997 wishbone and with some zip ties can be fitted to the m3 whisbone two. Think they currently go for bout 30 bucks a pair

[Estoril]

Best thing I know (also cheap) is using the 997 Brake air deflectors. The’re mounted to the 997 wishbone and with some zip ties can be fitted to the m3 whisbone two. Think they currently go for bout 30 bucks a pair

Thats what I'm doing this Spring, GT3 deflectors on my track M3. They can be had very cheaply. However I would not recommend it on a daily driver.

[bigjae46]

Thats what I'm doing this Spring, GT3 deflectors on my track M3. They can be had very cheaply. However I would not recommend it on a daily driver.

I thought these would be more friendly for a DD...not that it matters to me. Just curious, why would you recommend against? I'm thinking debris might be a problem and my home track has a ton of it off the racing line.

[Estoril]

I thought these would be more friendly for a DD...not that it matters to me. Just curious, why would you recommend against? I'm thinking debris might be a problem and my home track has a ton of it off the racing line.

Debris. Same reason BMW put stone guards in the stock brake air ducts (not to mention American's tendency for litigation).

[bigjae46]

Debris. Same reason BMW put stone guards in the stock brake air ducts (not to mention American's tendency for litigation).

Thx!

[heinzboehmer]

I thought these would be more friendly for a DD...not that it matters to me. Just curious, why would you recommend against? I'm thinking debris might be a problem and my home track has a ton of it off the racing line.

Purely anecdotal, but I've been running the Bryson ducts for a while —both on the street and on track— and have yet to run into issues with debris.

Debris needs to make an almost 90deg turn to get to the rotor, so most of it probably just bounces off the duct.

[SUPREM3///]

What's the take on the placement of these ducts?