Even the GR Yaris brakes are not spared!!!
Almost every OEM brake quickly reaches its limits. Even the well-designed and well-proportioned brakes of the Toyota GR Yaris.
SPEED Engineering GmbH
The brake system of the racing car
The GR Yaris already has a two-piece brake disk on the front axle, which is an enormous advantage. It allows the friction ring to expand under heat. This is because the pot does not form a single unit with the friction ring.
In addition, we have a 4-piston fixed caliper on the front axle, which is usually used in this design in racing and distributes the heat well over the 4 pistons. In addition, Toyota does not make the same mistake as Audi: too large a contact surface of the brake pad. On the Audi RS models, you often see a gigantic brake caliper with a brake pad that takes up half the disk. If 40% of the disk is in constant contact with the brake disk, only 60% remains to be cooled. Definitely not the best distribution.
What is the problem?
The turbine effect of the brake disk is usually used. This means that the inner workings of the brake disk are designed in such a way that as the rotational speed increases, the air flow rate through the brake disk also increases. Air should be “sucked in” at the center of the disc, which then flows out through the small chambers towards the inside of the rim. With the GR Yaris, however, this effect can only be achieved by changing the brake discs from left to right. This is because only then will the running direction of the brake disks point in the direction that allows the effect described above.
What’s more, almost every brake in its standard state is not up to the demands of the racetrack anyway. This is because the pads and discs are designed so that they only work in everyday use, where you will never have the hard braking maneuvers in quick succession as on the racetrack.
Let’s solve the problem!
Now that we have replaced the panes, we need to actively cool them! The GR Yaris already has channels designed to do just that. Unfortunately, these already end in the wheel arch liner. That’s not bad, but it’s not perfect either. Why not take up these openings and simply extend them to the center of the brake disc? Because we would drastically reduce the cross-section and would have a narrow kink in the guide, which would congest the air volume, because we have to leave room for the wide tires.
Why don’t we modify an anchor plate with an air hose on it? Steering lock is our biggest enemy here! This means that we have to use a relatively long hose, which in itself causes a power loss due to its length and already shows wrinkles in its normal state (driving straight ahead), thus impairing the flow.
We have thus built a double active cooling system by letting the OEM cooling do its job and taking more air from under the vehicle and directing it to our outlets on the wishbone using a short hose. These outlets do not move with the steering angle, but are fixed and therefore wear-free on the wishbone. The outlets are tapered towards the outlet surface, which increases the speed of the escaping air.
Now we have a wear-free, efficient PLug&Play system that additionally and actively cools the brake without impairing the function of the existing cooling channels.
To round it all off, we recommend the N39S brake pad, because we can say one thing from experience: brake cooling serves to support a good basic setup. In our experience, the endless pads (usually in combination with the OEM brake disk) provide a very good basis on which to build.
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