Brake day! (Crossdrilled/slotted)

yikes!

 

discs look sweet! how many miles on her?

 

Back in my younger days, I used to drive my modified 400hp japanese sports car on the race track often.
Did it >30 times across 4 different race tracks on the west coast.
I've also driven rental cars and other people's cars (hired driver) on still more different tracks across half the USA. Was lucky enough to even drive Nurburgring Nordschliefe with two different cars on two separate occasions.

I don't say this to brag or show off.

I say this to highlight that I have a lot of experience with pushing brakes to the limit and feeling and fixing brake fade issues to get the fastest lap times and to have fantastic consistent brakes when repeatedly slowing down as fast as possible from 130mph lap after lap.
I used to go through a set of pads every day at the track and replace rotors yearly due to cracks and fractures.

Why do brakes fade?
(trying to not go very deep in explaining this and loosing the audience)

To achieve any fade, brake pad or fluid fade, the parts need to go beyond their operating temperatures.

All vehicles sold at least since the 90's, do not reach temperatures to create fade during normal street usage. Only under consistent lap after lap of braking will you reach this.

You might also reach this in Arizona, 120F day, using the brakes for 2+ miles going downhill from a mountain. 18-wheelers run into this problem trying to slow down with a full load.

However, if you do feel any fade under street usage, even in the above example, if it's not due to old or malfunctioning parts, it's 99% brake fluid fade, not pad fade which drilled rotors could help.


Brake fluid's boiling temperature reduces with time as it picks up water from the air. Live in a humid area, and it's worse. Dry area, it'll last longer. If you shop brake fluid, you will see it's rated "dry" and "wet" boiling points. "Dry" is a fresh bottle, never exposed to the air. DOT 3 is average. DOT 4 is better. (always buy DOT 4)

Just replacing the fluid by bleeding the brakes, will give you better brakes.

I used to have abrupt transitions between brake pad braking and generator braking.

All I did was change the fluid, and it fixed it. Extremely smooth transition between the two.


I used to replace the brake fluid by bleeding the brakes, more often than changing the pads while on the race track to give the best brake feel.


We use our brakes on our hybrids, even less than regular street cars. That's why they last so long. They never get too hot. If anything, we suffer more from cold weather stopping issues because they run so much cooler than non-hybrid vehicles.


By installing the cross drilled rotors, if anything, you've reduced how well your brakes will work in the winter.
Brake pads work on a bell curve and have a window of operation. Pads for the street have a much wider operating window (work at a wider temperature range) than pads built for the race track.
See the following chart as an example of different pads from AP Racing.



Cross drilled and slotted rotors do look cool though.

Just don't try to convince a mechanical engineer or race car mechanic that they help reduce brake fade on your hybrid. You'll embarrass yourself. Regular street car owners have embarrassed themselves for years on this. You'll embarrass yourself more with a hybrid.

The improved feel you felt from changing the rotors, was not from the rotors, but from other things you changed at the same time. Fluid, pads, calipers, etc..