Brake Pad & Rotor Upgrade

More fun facts:
2nd gen Prius used a 255mm x 22mm brake rotor so toyota added 3mm to the rotor for longer life lol
Pre-08 the Toyota Corolla /Matrix used a 275mm x 25mm rotor and a older pad style
After 09 the Corolla /Matrix switched to 275mm x 22mm rotor and the pads look similar to Prius pads
so you can go for thick rotors or thin rotors
if you want 283mm rotors go for 2022 Prius Prime rotors and caliper brackets. Toyota even lists them as Corolla/Prius Prime

FRS and Toyota 86 use Subaru sizes at 100mm x 5 and a 56.1mm center bore. Prius/Corolla/Matrix is 54.1mm center bore not an exact fit.

 

for me, since I am using the FRS Wheel Bearing & Hub Assembly for the Rear in my AWD conversion, it works out perfectly!

 

Is the expectation here that replacing the OEM friction brakes with supposedly upgraded ones will cause a statistically significant difference in the amount of energy recovered through regenerative braking?

The car prioritizes regen over friction brakes in all situations except panic stops, or if the power management control ECU decides it doesn't want to charge the traction battery under the current conditions (extreme battery temperatures, high battery SOC). In normal conditions the friction pads engage only once regen has slowed the vehicle down sufficiently, and from that point on until the vehicle comes to a stop no energy is recovered.

Given that, I'd be interested to know why one would expect any change in the energy recovered by swapping out a component that only comes into play after the vehicle is done recovering energy.

 

You know, all I know is... after installing cross-drilled and slotted rotors with ceramic pads on my 2013 Plug-in... the same steep downhill road I take all the time heading home I could never generate more than .9 miles of EV range... after installation, 1.3 miles has been the max and average these days.

That said, I plan to use the stored data variables to confirm this on the Prime I have. Storing the logged data for a few months now so I have a good baseline to start from.

 

And for sure there is a way to test that hypothesis, no matter how inexplicable and contrary to our understanding of the HSD it might be.

At minimum, the following conditions would need to be satisfied in order to be even test for a significant difference between the two cases:

1. Data would need to be collected under the exact same initial conditions (HV battery SOC, HV battery temperature, ambient temperature, engine load, etc.)
2. The same deceleration torque demand profile would need to be applied over the course of the test.
3. Two sets of readings would be needed, one with the OEM rotors, and one with the aftermarket.
4. The number of readings in each set would need to be calculated beforehand (assuming a statistical power of 80%) using the expected mean and standard deviation of the "before" readings, and the expected mean of the "after" readings.

A one-way ANOVA of the data would be enough to reveal any differences. "I-did-X-and-observed-Y" type reports wouldn't mean much, because a lot of such observations are, in fact, due to random chance.

 

Agreed, the best part is, no matter how much we think we might understand the HSD there is always room for unlearning inaccurate information and learning new information.

Let me ask you this... A 2013 Plug-in with advanced technology package cruising on the highway with the dynamic cruise set to 69 mph going downhill in Colorado... do you think it is impossible for the car to brake itself keeping the speed at 69 mph for miles and generate enough energy to fully charge the HV battery resulting in 14 mile EV range?