Drift Car Brake Development

The complete rear brake system after an entire season of Formula D abuse still looks brand new!  Both the rotor and the pads have very little wear, a far cry from the old system.

Dai was pretty happy with the performance of the old brakes but what he noticed right away was that the new brakes were much more consistent in performance and the pedal effort and brake lever pull required to lock the brakes was lower and more consistent. A lower effort and good stopping power were due to the larger pad area, increased hydraulic gain in the front calipers, and stiffer front and rear calipers. What everyone is super impressed with is how much better everything wears to the point of several orders of magnitude longer pad and rotor life.  Despite being much more substantial, the new Stoptech system is only slightly heavier than the previous brakes as well.

With Stoptech, our team has state of the art brakes which should be enough for any anticipated technical gains in power and tire grip in the near future!

Sources

Stoptech

11 comments

  1. What is the purpose of the cross drilled rotor with integrated slots from the drilled hole? Does it prevent cracking from thermal expansion?

    I looked all over Wilwood’s website but couldn’t find those particular rotors.

    1. Those are thermal expansion slots, which certainly would have been to extend the time before cracking started. When iron rings heat up to competition temperatures, the expansion must be planned for. If not, then iron will crack sooner (beyond the normal “crazing”). There are better ways to deal with this, yet the sprint car/dirt track market typically operate on tight budgets,, so this would be one way to get there.

  2. On the one hand it seems funny that Stoptech keeps coming up… but they really are at kind of a sweet spot. I know from pricing stuff up what a quantum leap up it is to go to the next tier of brakes, and I’m not sure, say, an Alcon TA6 (same pad shape too, I think) is more than incremental gains for the 4x (or so) price jump. I like that some of the newer calipers they’re doing are using more common racing pad shapes than the Brembo shapes the 40 calipers use.

    1. I really like StopTech because they have the tremendous range of piston sizes which enables them to match OEM proportioning. People don’t realize how critical this is and how it affects a car’s electronics nowadays and if the car is an older car, how it affects pedal feel and balance. That’s not the case in this car because it is a race car with a pedal box but for cars with a single master cylinder, it’s amazingly good.

      For their street kits, Stoptech also has rigorous validation testing. to assure the vehicle dynamics are safe. When developing frictions and caliper systems, they have OEM level brake dynos and do extensive validation that way as well. They also have a PHD tribologist and develop their own frictions in-house.

      Sure Brembo and AP have some more advanced calipers but those are not the ones people typically use for street and grassroots applications. Those are no better than StopTech. StopTech’s engineering office is right down the street from us and they are very generous with help and technical support.

      Brembo or AP’s engineering department would probably roll their eyes at the thought of working with a drift Team or not even have any knowledge that drifting has advanced to a high-level motorsport.

      1. Yeah; I have to respect the niche that Stoptech has carved out for themselves. It was a little funny because until I looked it up I didn’t realize the STR60 was using as big of a pad as it is; I like that and a lot of their recent design decisions, and that’s leaving aside the validation they do.

        I look at it sort of like… yeah, you end up using Stoptech in a lot of builds. But I know walking pits and looking at prototypes and GT cars and stuff in the 90s to recently (there’s more good options now but you know what I mean) basically everything would have Penske shocks… well, sometimes there is just a “best” solution given constraints.

  3. The pad surface area doesn’t change braking performance, just pad life.
    It looks like that kit was a little over engineered for this setup – you could have gone lighter and replaced twice per season? It just depends how much different rotational weight/inertia makes to chassis and tyre dynamics. And team budget of course!

    1. We didn’t just throw some stuff on the car, I worked with StopTech’s engineering department to come up with a system that would solve our problems and improve our brake performance. Pad area doesn’t change the amount of brake torque produced but it can greatly affect the fade characteristics of the brake besides just affecting wear! The system is not overbuilt, it is sized correctly to take the thermal loading that the car produces. With our previous system, we had to run a very high mu aggressive pad with a narrow effective temperature range. Brake temperatures were sky high, the rotors would glow red hot and wear was extreme. Consistency was also an issue due to the pads narrow temperature operating range. Overall performance was adequate. Our new system is only 1.5 lbs per corner heavier in the front and 1 lb per corner in the rear. We are running a 335mm low mass front rotor, not the internally thicker and heavier high thermal capacity rotor. To reduce the capacity would run the thinner rotor, you would only be saving weight with the vane thickness not by reducing material in the friction surface, not worth it in my book.

  4. @Mike Kojima – how important is lightweight brakes (unsprung weight) and small discs (low inertia) for drifting suspension and chassis setup?

    1. Well, you have to have enough brake to do the job, and too much is just weight in a bad place. Having enough brake is the most important thing.

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