Quote:
Originally Posted by DM7
The design is sound; air is blown at the centre of the brake rotor.
I only have anecdotal data to comment on the effectiveness. I have seen impact marks from road debris on the scooped part of the dust shield. The duct also blows a lot of water at the brake rotor when driving on the highway in the rain. Water on the brake rotor makes the top of the pedal stroke ineffective at slowing the car during the first brake application after a long rainy cruise at speed. I have experienced this wet rotor effect on all cars I've driven; but it is most pronounced on the BMW.
On my BMW 228i, in addition to the brake cooling duct and the heat exchanger inside the wheel well. There is a third duct outlet that is tall and narrow beside the heat exchanger; where the bumper cover meets the wheel well liner. I think this duct is used to blow air out the front of the wheel well and around the front of the tire. This curtain of air is probably used to reduce the wake of turbulent air generated by the rotating front tire to reduce drag.
BMW has put a lot of thought into managing the air in the front wheel wells. It probably cost a lot to develop all of these feature so it is unlikely they would be completely useless.
My 228i has opposed piston fixed calipers front and rear; but I don't like the brake pedal feel. The top of the pedal travel has too much brake booster assist, has very little feel/feedback making it tricky to modulate. During track driving I found the lack of feel is more of a problem when releasing the brake pedal as opposed to applying it. Applying the brakes in a braking zone I can quickly apply the brake pedal past the top part of the pedal travel and slow the car effectively. However releasing the pedal and reducing the brake force smoothly through the top part of the pedal travel is difficult to do because of the lack of feedback/feel. I prefer the pedal feel and feedback in my FR-S (floating calipers all around) much more. The Supra will only have fixed calipers in the front paired with floating calipers in the rear. Forgoing the rear fixed calipers is either a cost savings measure or there is no benefit in terms of feel/feedback to justify having them. In a couple Supra prototype drive reviews I read the authors did say they disliked the brake pedal feel.
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I know its difficult without a before/after, but did you notice effectiveness of air flow cooling during hot laps ?
