pejoda

My 2003 Performance model (Canadian) has stock brakes which would fade at a track meet. This spring I installed Hawk HPS pads and changed the fluid to DOT 4 which cured the fading. I painted the calipers at the same time. I now find that after a track event, the paint on the rear calipers is scorched - the fronts are fine. If it wasn't for the paint discolouration, I would never know that the rear brakes were over heating.

Has anyone else experienced this? If so have you found a simple solution? Has anyone installed any kind of air ducting to the rear brakes and if so how?

Michael-Dallas

Changing caliper color doesn't necessarily mean you've overheated the brakes. It just means brake temps have exceeded the paint's rated temp.

pejoda

Thanks - the paint can says good for 900 degrees! They say that F1 car brakes reach 1000 degrees! Reason is, I'm sure, the size of the rear brakes which is about 1/3rd the size of the front brakes so they are doing a lot more work than the fronts.

MY350Z.COM

iTrader: (2)

that is completely wrong. search for "brake bias".

The Mike

when you brake the center of gravity shifts foward meaning that your front brakes always do alot more work than the back brakes,.. hence why they need to be so much thicker and wider. It wasn't just randomly thought to put skinnier brakes in the back.

Protegimus

Performance model also has the brake 'Limited Slip Differential' (LSD) as part of the TCS (Ref.: manual BRC-96)

Even with VDC disabled via the dash switch, the brake 'LSD' remains active, so the rear brakes are probably doing a lot more work than you might expect when you are on the track.
The Hawk pads probably generate a lot more heat than the standard pads.

You can manually disable the brake LSD without affecting ABS operation, but handling will be less 'safe' without the electronic aid. Your car does have a proper viscous LSD though, so you could test the car out with this setup to see how it handles and whether rear brake operation is reduced enough to affect temperatures.

JSON

You joined in 2004 and this is your first post? That's awesome.

Sorry for going offtopic. Continue

Protegimus

Hey Jason, I'm in the UK and regularly take part in the forum here; usually just read the US forums for the different perspective and experiences.
Thought I might be able to shed some light in this instance, so decided to break my duck

Likewise...

mberthia

iTrader: (5)

First turn off the TCS as it engages the rear brakes. On the track, I find that it is too sensitive and once it engages, it stays on until I let go the gas pedal momentarily. Unfortunatly, the TCS was engaging tracking out of a curve at WOT before a straigth. This is not exactly were you want to let off the gas because the TCS has engaged. I now turn it off.

There is a difference between fluid boiling and pad fade. If the pedal goes to the floor, ou boiled the fluid and aire bubble are in the line. If the pedal is still hard but your not slowing down, then the pads are fading because they hotter than their effective range. If you don't have any of this then there is no need to worry about the paint changing color. Even the Brembo's change color.

You could change to a track pad like Hawk Blue (I purchased some but have yet to try them). The HPS is a street pad although if it does not fade, there is no reason to change other than maybe it well wear faster than dedicated track pads. Hawk does not make the HP+ for the rear.

Which track did you go to ? I'm from Ottawa originally but now live in Detroit.

MustGoFastR

iTrader: (13)

How?

pejoda

Thanks for the input. Good food for thought here. I have not tried running without the TCS engaged but I will next time. The brakes actually perform very well. The Hawk HPS and the DOT 4 work well. Good pedal and no fade after I put in Hawks and DOT 4. They were fading before which is why I made the changes that cured the fading problem. If I had not painted the calipers this year I would not have known about the overheating but there is no question that the rears are discoloured but the fronts are not. My dealer has no opinion or recommendations on this. Fellow trackies suggest removing the backing plates and installing some cool air ducting onto the calipers. Removing the backing plates is quite an operation and I haven't yet decided whetehr to tackle this.

I think ideally it would be good to cut a hole in the backing plate and weld a tube into the hole onto which a duct hose could be attached and then tied to the suspension in such a way that it faces forward and picks up and directs cool air dircetly onto the caliper. This way one would have the benefit of both the backing plate and cool air.

I could go to larger brakes of course but frankly I don't think I need to if I can just cure this overheating problem.

I have been run my car at Cayuga, Mosport and Dunville. Last year, on stock pads and DOT 3, I was experiencing brake fade at the end of the straight at Mosport braking from 190 kph for turn 8. After changing pads and fluid and painting clipers I noticed the burned paint. I Last weekend I was at Dunville where we were warned that the track was hard on brakes (ie: don't use the hand brake after a run!) After only a few laps I smelled the brakes and came in and found the left rear was smoking! I then modified my braking habit by trail braking. Before I would brake straight line into the corners and lift off the brakes before turning but the trail braking seems to be easier on the brakes.

Appreciate your response!

mberthia

iTrader: (5)

Borrow a pyrometer to check the temperature of the wheel, tire, caliper, rotor etc.
I don't think you are getting 900F. The paint can may say that it's good up to 900F but I still would be supprised if you are above 700F.

The best way to brake and keep them cool is to brake hard, all at once to be done with you breaking as fast as possible. Keeping your foot on the brakes at a lower modulation (less braking but for a longer time) will heat up the brakes and do more harm. This is very different than when driving around town...

Trail braking is something else. Not everybody agrees whether it's really faster or not. It can be used to turn the car easier by getting the rear end lighter and sliding to oversteer. Can be dangerous if you are inexperienced.

EnthuZ

iTrader: (2)

May I sugget you remove the rear dust shields. Someone posted a detailed how-to a couple years ago............

OEM rear non Brembo brakes are too small for track use.

Period.

Jason@Performance

iTrader: (11)

yeah.. for some reason when you heavily track the car the rear brakes get super hot... my rear calipers basicly seized up and are always claping the rotor... sounds ugly...

you probalby are going to have to re-build your calipers... in the rear that is...