Hi, I have a Makinnen EVO 6.5 here in Australia. It has Brembo Brakes identical to EVO-8 I believe,

The car is used for some road work and track days (sprints)
I'm running competition pads at Mallala (a very severe cuicuit for braking) and having overheating problems (boiling fluid and cracking rotors).

Part of reason is probably my poor warm up technique giving thermal shock and cracking, but as well as improving driving,I'm looking for ways of getting heat out faster.

I've had advice to remove back plates for improved airflow.
I've also had advice that removing the back plates can cause uneven heat transfer and hot spots.

So my questions are:
(1)Does anybody have any actual experience without back plates?



(2) Does anybody have any experience with the little Ralliart scoop type cooling ducts?

Thanks.

 

When I first bought my Evo 8 in early 2003, I installed the Mitsu brake cooling scoops and partially cut-away the backing plates. I left enough backing plate to provide a heat shield for the ABS sensor and a mount for the ABS wire, plus enough meat to the mounting points for the backing plate itself. I don't have a lot of mods on the car, but it is pretty fast. I've used it at a number of tracks in the Midwest that are pretty hard on brakes (Road America and Blackhawk Farms), plus autocrossing, etc. With the right brake pad (I use Ferodo 2500), I don't have a significant problem with brake fade. I was also happy with the stock pads for track use with the cooling scoops and cut-out plates.

I've never directly compared the brake performance on my car to a set-upwithout the scoops etc., but my experience with the stock pads is contrary to what most people report here. If they weren't so expensive, I'd still be using the stock pads on the track. As long as they are broken-in properly, they worked very well for me. This leads me to believe that the scoops + backing plate mod really helps with brake cooling.

Some others here have reported removing the plates entirely with good results. I'm still a bit wary about heat damage to the ABS sensor, though.

Bottom line is that the scoops plus modding (or removing) the backing plates worked well.

 

Good information, thanks a lot.

 

I removed the backing shield altogether. had the scoops for awhile, untill I ran some hose.
scoops were OK, I just managed to break one off.
I always run a cooldown lap, or cruise down a side road without touching the brakes. my calipers are just a bit darker than new, still red though.

 

I'm having some serious brake overheating issues as well and have made/will be making the following changes.

1. race pads. No more crossover pads.

2. Good brake fluid - currently running ate super blue, but will be moving up to motul once I run out of my current supply.

3. 2 piece rotors

4. remove the dust shield - I know of a number of people who have done this with good results. Its hooked up by only two bolts, and you can zip tie the abs sensor wire in place easily. No increased problem with hot spots etc.

5. ducting - makes a huge difference from what I understand. All the guys that race evo's that I know of in Ncal have ducting. I'll be working on some soon. From what I've heard, the rallyart air guides dont help much, and they're expensive when you break them.

 

What brake fluid are you using that is boiling? How many rotors have you cracked? I ask so I can get an idea of just how hot your brake system is getting and try to seperate maintenance problems from manufacturing problems from actual heat problems.

Regardless, doing what Evo442 said is a good start, although I would go to the 2-piece rotors as a last resort. Just because of the pricing.

 

This has been mentioned before, but HOW you use your brakes on the track is at least as important as your braking system.

After the brakes are warmed up (gently and slowly!), it is best to use the brakes in a short-and-hard manner. You want to minimize the contact time between the pads and the rotors. This minimizes heat build-up. "Riding" the brakes for a time before braking hard is one of the worst things you can do. This heats up the brakes without providing much slowing down.

Hardware only goes so far, technique is also very important. (Hey! I've seen that comment in other "forums"!!)

 

Thanks for the replies.
I'm only using DOT4 fluid and that would explain the boiling.

To give you an idea of how hot they get, the front calipers are now almost black and the bigger piston outer dust seals are cracked.(race cars here run without them on track)
I'm using Galfer Gold Sintered on front (excellent) and some local race pads on rear that are similar to Pagid blue.
Have also used Pagid black on front (very good).
The std Brembo pads (made by Galfer) were pretty poor at the temperatures on track.
I always run a cool down lap and run up and down a nearby road to cool brakes off.
Am about to buy 3rd set of front rotors.Original set developed some cracking after track use following machining (within limits).
Second set now showing cracks that are still limited to middle half of braking surface, but am worried they will grow.
So that's why I'm looking for better cooling, as well as better technique.
(Trouble is, I'm getting pretty good lap times, so don't want to back off!!).
Thanks again for the replies.

 

You are sure the fluid is boiling, and your pads aren't just fading?

Boiling Fluid = mushy/increased pedal travel

Pad Fade = Solid pedal with reduced braking performance

If it's pad fade, you might go with slotted rotors to release the gas between the pad and rotor. Avoid cross-drilled rotors for track use, they crack too easily.

 

Thanks Darryl,
I'm sure it boiled. The pedal went completely to the floor with absolutely no braking, even with pumping. A bit embarrasing at about 110mph approaching a tight 40 mph corner. Came good when cooled off.

 

...also, do not use "turned" rotors (never!). Esp on a track! Your removing the very material that you're generating heat in.