On track braking issues

Magpie · Postby **Magpie** » Thu Sep 04, 2014 7:32 am

Agressive pads will cause more rotor wear if they are not used in their operating range.

So far with my set up I have done 3 full tracks days and pads/rotors are still OK. However, only about 200km road km, the brakes are horrible cold and squeal like a stuck pig.

sailaholic · Postby **sailaholic** » Thu Sep 04, 2014 7:43 am

Plenty of people use a1rms on the track up here and find them brilliant deviant. I wonder where the difference is,

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greenMachine · Postby **greenMachine** » Thu Sep 04, 2014 3:32 pm

The key here is pad choice. Rotors, callipers, ducting all play a part as well, but pads are the key variable. Again, particularly for a turbo track car, I can't see one set of pads doing street and race duty, so when you put your R-specs on, put your race pads in - it is not that big a job (at least on the fronts, you may be able to get away with dual duty pads on the rear).

Ideally, you would have two sets of rotors too, so you are always running pads on rotors that have been matched to the pads. Changing the front rotors is NBD when you are changing pads anyway.

For pads, I would talk to a vendor who sells race pads, and preferably races too, and be prepared to experiment with different compounds. Stick with that vendor unless/until you have exhausted all his options, otherwise you will risk just chasing your tail and spending lots of money by chasing vendors/brands, not solutions.

Good luck.

:mrgreen:

PS Unless I am mistaken, Wilwoods are not street legal ...

Magpie · Postby **Magpie** » Thu Sep 04, 2014 4:10 pm

greenMachine that is what I have. A set of track rotors and pads as well as a set of pads/rotors for road use as well as 2 sets of spare rotors that are ready to have pads bedded in on.

Each time I swap the track/road the pads/rotors are kept together. I also take the time to note the thickness of the rotors to see how they are wearing. However at the moment I do not put the road stuff on because it is hardly road dríven.

I also agree pad choice plays a big part, however keeping them cooler allows a greater range of pad choices.

track_addict · Postby **track_addict** » Thu Sep 04, 2014 7:47 pm

No silicon has been anywhere near the brakes. Project.r.racing, can you explain the theory of incorrect pressure from the piston causing pad damage? Are you saying the piston isn't giving enough pressure and due to the high temps and speeds, the pad can't bite the rotor like it normally would and just glazing?

Braided lines and better fluid is at the top of the list at the moment.

On the point of a possible internal master cyl leak, when I press and hold hard on the pedal it doesn't drop at all. Very occasionally, when I'm braking lightly to slow down for lights, just as the car comes to a stop the pedal drops a tiny bit with no increase in stopping force. Pump the pedal once and it is back to normal. An internal leak has crossed my mind.

Greenmachine. I feel this might be the case and I will have to have a set of track pads/rotors. I was hoping to avoid this due to cost. Its an easy job to swap all the pads/rotors over, so far I've got it down to a cruisy 1.5hrs. Its just yet another thing to do before a track day.

I've had a quick look at the carbotech and winmax websites. Looks like I will definitely have to go to a race pad to get the same or better max temp as the A1RM's. I've pretty well resigned to the fact of having to run a seperate set of pads/rotors, which should fix the issue of destroying pads but I doubt it will fix the strange pedal behavior. Is it possible there is an issue with the ABS?

I have thought of ducting but I want to try make the set up work without them.

Pics of the pads.

I'll email the guys at GSL tonight to get there thoughts as suggested.

AndrewJZX100 · Postby **AndrewJZX100** » Thu Sep 04, 2014 11:29 pm

Wow those pads are a bit 2nd hand lol

I ran Hawk HP+ on mine when I went out, got 3 track days out of them so far and theres a good couple more in them. Stock rotors, lines and calipers.

I was only running around in 1:30s and 1:31s at my quickest though - 20thou kay old chinese rubber with too many heat cycles to mention meant I wasn't testing the limits of anything but my patience

Having said that, I did get a spongebob pedal after a few sessions. Was just gonna rock some braided lines and Motul RBF600, as I only had Penrite Racing fluid (310ish* C boiling point) in it at the time.

track_addict · Postby **track_addict** » Sat Sep 06, 2014 11:49 am

Andrew, sounds like you were your own worst enemy! I'm into the 1:25's now, so the cars working pretty hard now. Did you bleed your brakes after to get the pedal back or did it just come back itself? The penrite stuff seems to be pretty good in terms of its temperature range. The Motul fluid can only handle 15-30deg more than the Penrite.

StuwieP · Postby **StuwieP** » Sun Sep 07, 2014 1:44 pm

Just to throw in another alternative: I've run hawk blue 9012 compound, but I have nothing to compare with as I've only done a few days so can't speak to their longevity, though they still have plenty of meat left after 4-500 track kms. I'd expect upwards of 2000kms? Slow car though...
Wouldn't use them for long on the road, despite the fact they grip really well when cold, they also eat rotors pretty quickly.

No trouble with the brakes over full days, no special brake fluid, stock everything except the pads, pushing the car as hard as I could too (so perhaps not very...), but running fairly short bursts, not 20-30 laps at a time.

Good luck!
Stu

AndrewJZX100 · Postby **AndrewJZX100** » Sun Sep 07, 2014 8:31 pm

Yeah going out on plastic tyres isn't great for lap times but I'm a drifter so I'm happy to slide around in the low 30s, just gotta deal with the inital understeer lol.

As for the unfriendly pedal, I'd sporadically pump the brakes in the pits and on the out lap and it'd usually be ok. Also as I drove home, the first stop at the pub in mallala would be spongy but after that it firms up.

track_addict · Postby **track_addict** » Mon Sep 08, 2014 7:41 pm

Pumping the brakes does nothing for me. Just gives me no confidence haha. For the next sprint (final for the year) I'm gonna chuck in another set of A1RM's and use different grease on the slider pins. I was using a copper based lube (Loctite C5A) but have since read that it eats dust boots and can burn off, apparently. Ill probably chuck on some braided lines and change fluids to a different brand.

After that I may just have to save up for this. http://www.flyinmiata.com/index.php?dep ... %201990-05

Definitely would make the car over braked but would save having a second set of pads/rotors and the time will come when it gets a proper ECU and some power!