lookstoomuch

I installed these and my unscientific test led me to conclude they were not very effective and this am thus suspect of the performance of the GT3 ones as well. Testing involved installing on one side of the car and measuring brake pad thickness after each event throughout the year. I also drilled holes in my dust shield where the air would flow based on tests with a leaf blower. No significant difference in pad thickness after 1 year between the side with and the side without the duct. Not knocking Honed's product, it was decent and if you do buy shipping was reasonasble from what I recall.

Maybe my expectations were too high. Some have suggested there is not enough pressure in this area of the car to generate airflow against the ducts. Be very curious to have someone like roel03 chime in.

It would seem that if Porsche is installing them they must do something OR Porsche has something in the body design to direct high pressure air this way.

s2000Junky

^^^Pads and rotors are wearable/disposable items so pad life really wouldn't be the sol basis for my test. Reading actual temp differential between sides would have been great to know what was/will happen. I want to know the rotor and hub/bearing temps are lower and therefore bearings last longer. I want added reliability and brake effectiveness through an entire lapping day without spongy brakes/cooking fluid. Rear brakes on the s2k run very hot.

Nate Tempest

For what it's worth, Porsches do have channels to direct air toward the ducts. Here's a picture looking back toward the duct from under the front of my 997 Turbo:




But yeah, it would be very interesting to see actual temperatures with these, since pad wear wouldn't necessarily be obviously accelerated.

lookstoomuch

Agreed it was an admittedly unscientific test....with all of the talk of reduced pad wear when rotor temperatures are reduced I figured there should be some difference.

I forgot to mention I did keep an IR temp gun with me in the car and a handful of times tried to get readings directly after sessions of temperature differences left vs. right rotor/hub area and found no differences there either. Sometimes the side with the duct was hotter than side without.

roel03

I would not expect these to do anything on our cars. Air inside the wheel well is so violent and turbulent it should not be relied upon for brake cooling. All manufacturers try and evacuate wheel well pressure as it's a huge drag compensator, which is why fender exits are so prevalent. I could see it being a little useful if a car is equipped with a diffuser like the one posted, but overall it's a waste of time. I would say on any car that sees real track time that they should get proper ducts. These actually would add a fair bit of drag as well.

For ducting inspiration, don't look at production cars. Even though the GT3 these came off of is a proper sports car, it is not a dedicated track car. On the IMSA cars, we run ducting not only to the rotor but to the caliper as well. That air could easily be harvested for more downforce, but brake cooling is way too important to ignore.

I hesitated to post on this thread since it would sound biased, but for as cheap as brake ducting is for our cars, do it proper. With brake cooling you want as consistent performance as possible. I haven't felt brake fade in years and no longer have to flush fluid after track days. Temps were 150 degrees cooler in the front and 120 degrees cooler in the rear in my latest test.

S2000_916