Track tested for 15 hours by Road & Track!
Our testing shows that ND differential temperatures can reach over 300F on track - and they cool down very slowly. This means a high likelihood of differential damage when you're running on the track. Mazda knows this, it's why the MX-5 Global Cup Cars are required to run a high-dollar cooler.
Their design doesn't work on cars with a muffler, however. It also requires a fan to function and requires expensive modification of the diff housing. We didn't like that, so we went a different way.
Does it work? In our testing, we saw temperatures just over 200F even when lapping Laguna Seca for hour after hour. Yes, that's nearly a 100 degree drop in fluid temperatures.
The cooler is mounted by the back axle, fed by a small kick in the undercar ducting. Everything is well protected and above the level of the subframe in case you have a little whoopsie. The fluid is circulated by a dedicated pump with thermostatic control, so your fluid is maintained at the ideal temperature regardless of what you're doing. No modification is required to the case or the car for installation.