AP Racing Brake fade after 15 minuts of track time

[2001ultima]

All, we do 20 minute track sessions. After about 15 minutes I will not longer have brakes. My brake fluid has been changed and I have a new front master cyclinder. Discs/Rotors and pads are due to be changed soon. After about 25 minutes of cool down, the brakes are fine again. I never have the problem on the street. Need to get this fixed.

[AlexCim]

It's a light car, with big brakes. You really shouldn't be experiencing brake fade. Doing the following should help you avoid brake fade.

- Put ducting to point cold air towards the brakes
- Vent your wheel arches
- Vent your side pods
- Put in higher temperature pads
- Stop riding the brakes

[UltimaCH]

Amazing to hear you have brake fade despite all the brake ducting you have installed as per the photos on your site.
What brake fluid are you using?
What type pads installed?
When was the last time you flushed the brakes?

[macgtech]

Is the pedal going soft or is the car simply not slowing down? If its the first, you need to use fluid with a minimum dry boiling point of 600F. AP Racing 600 should do the trick.

If its the second, you need better pads. The factory have reasonably priced track pads which should solve the problem. These are not the standard Mintex 1144 supplied.

[donkeasy]

Sorry for saying this possibillity:
Make your braking time shorter (later) and stiffer (heavier).

[macgtech]

donkeasy said:

Sorry for saying this possibillity:
Make your braking time shorter (later) and stiffer (heavier).

This would make matters worse, as you are reducing the time for the heat to dissipate.

[BenGTR]

I got Ferodo DS2500 with the brake from the factory.

[donkeasy]

macgtech said:

This would make matters worse, as you are reducing the time for the heat to dissipate.

Yes, give your brakes time to cool down,
short heavy breaking and foot off the pedal to give it time to cool down for the next corner.

[Storer]

I have standard discs and trackday pads from Ultima and so far my brakes only seem to get better when they are really hot.

I used some cable spiral wrap to give added protection to the brake lines and this has melted where it touched the calipers, so they do get warm!!!

The tyres should be the limiting factor when braking heavily, not the brakes.

If you have the AP brakes then new trackday pads and DOT 5.1 fluid should solve the problem.


Paul

[2001ultima]

Everyone, Thanks for all the feedback. All good points.

Answers: Pedal going soft, fresh DOT 4 fluid, I have air ducting, I'll try a different braking stategy but I would not expect to have this issue.

I'll report back when I figure this out. I recently changed the master cycliner and never had the problem prior. Maybe I got a bad one.

My discs and pads will need to be changed soon.

[Paul.B]

The DOT 4 fluid may well be the problem. I would upgrade this before you change anything else. Go for one of the one mentioned in the previous posts, AP 600 or a quality 5.1 I personally prefered the AP fluid supplied with the kits.

Good luck.

[AlexCim]

Track day specific pads from the factory.... why is this the first I hear of these?

I can't remember what pads I got with my car, but I hope they're the best ones... I got the BBK and I think they were Ferodo, don't recall "Mintex" from anywhere. Are these the track day ones?

[macgtech]

The 'DOT' rating on brake fluid is a bit misleading (or can be). You should ignore the rating and look at the dry boiling point. You need something which is 600 deg F minimum for track use. The AP600 fluid or Motul RBF600 fluid will work fine.

[macgtech]

AlexCim said:

Track day specific pads from the factory.... why is this the first I hear of these?

I can't remember what pads I got with my car, but I hope they're the best ones... I got the BBK and I think they were Ferodo, don't recall "Mintex" from anywhere. Are these the track day ones?

Ring the Factory and ask. From memory, the track pads they offer are Mintex.

[cptsideways]

Also worth checking the brake bias situation, a Handheld IR temp gauge from maplin for £20 will tell you whats going on at the discs. My bet is the bias is set to one end & its overheating that end.

[Storer]

The pads I have are Mintex Racing 1292 F4R


Paul

[macgtech]

Storer said:

The pads I have are Mintex Racing 1292 F4R


Paul

Yes Mintex F4 is the factory spec trackday pad...its all flooding back now!

[ROWDYRENAULT]

My opinion only, this is a great subject, made better by MagTech et al, because the first answer out of everyones mouth wasn't oh those A.P. the factory offers are..... you need to buy the new biggest, baddest. chrome plated ceramic brakes available. Considering the cars weight proportionaly if these brakes are fading I agree that you shold be looking at fluid. pads and air ducts in that order. If you are still fading the brakes after 15 minutes of use then you must be the king of late braking drivers and you need to go see Ron Dennis for a new line of work. Lee

[2001ultima]

ROWDYRENAULT said:

you shold be looking at fluid. pads and air ducts in that order.

Ok, good suggestion. I will start with a fluid flush and change the brake fluid typ. I have plenty of air going to the brakes with my customer grill work. Pads will need tp be changed soon. I do seem to come up fast on other as we approach a turn but that is because the Ultima is some much lighter then the other car and have more time to slow down.

[200Plus Club]

pagid pads are so much better than the ds2500 mentioned for trackday use its untrue, altho they are an expensive pad, if anyone is thinking of a trackday pad i'd recommend them every time.