The regular brakes are said to "fade" under heavy use. Could this problem be solved by putting in aftermarket brake lines and different pads?

I am guessing that a great deal of the poor performance is due to the stock rubber lines expanding when heated and the factory pads being of poor quaility.

 

no no, its from the rotors becoming heatsoaked, they can only absorb so much till they are just burning up and can not turn motion into heat any more. better brake pads might help marginally, SS lines would just make the brakes a bit firmer, no more expansion in the lines.

but in the end, you just need larger rotors that are slotted and/or drilled that can absorb more heat, and dissapate the heat and gas buildup more efficiently.

 

Also, I think "heavy use" basically means track driving. From what I've read, it seems like a few hard stops from 60 or 80 are not too bad, but an hour of them can get things quite heated up.

-D'oh!

 

I bought the ss lines from stoptech and will put motul 600 in them when I get them. I'm going to VIR in Feb and will see if they do any better. Check out the end of my post in the Racing forum, a good discussion of ss lines from an rx7/nsx page. SS lines might not be the answer!?

 

in stock form both stock and track brakes can grip better than the tread, meaning both are able to engage ABS. which means nothing you do except increasing traction of the tires will slow the car down any faster.

but after 5 or 10 halts track can still make ABS work, and stock cant.

 

Exactly how does removing metal from the rotor allow it to absorb more heat? X-drilling has nothing to do with heat or it's dissipation.

Not likely.

Much more likely.

 

I don't think cross drilling helps at all for cooling rotors. However in general the more surface area an object has, the quicker it can cool off from air flow.

Just look at the heat sinks inside your computer.
--
Jeff

 

Cross drilling helps cool and release the gas that is created as the brake pad is dipressed on the brake roter. The slotted aspect helps clear away the brake dust from the roter.

thanks,
Greg

 

I thought that slotting and cross-drilling had more to do with some sort of gas expansion than cooling. Also, don't the slots perform a sort of "cleaning" action that removes glazing?

I don't know much about brakes, but I would suspect that the rotor material has more to do with the heatsoaking problem than anything else, but correct me if I am wrong.

 

That's what I've always heard. But apparently that only applies to old technology brake pads. Modern brake pads are not supposed to boil off gasses anymore.

I've heard cross drilling is more for style nowadays.
--
Jff

 

True. Surface area is what determines how quickly a rotor cools. If you actually calculate (and I have!) the amount of extra surface area you create from drilling holes in your rotors, you'll come up with less than 1% area increase (I think I calculated closer to .1%). Not nearly enough to come close to affecting how quickly your rotors cool.

99.99% of all brake rotors are cast iron. If you're really special, you have a Porsche GT2 with ceramic rotors. Rotors are not made out of steel because iron has better thermal properties than steel (and iron is cheaper too).

True again. Back in the day when pads were made of asbestos, they would fade at much lower temps than modern pads. Holes gave the outgassing somewhere to go. Modern pads don't do this, certainly not on the street. There *may* be some benefit to slotting a rotor to eliminate pad glazing and providing a leading edge for "bite".

As someone mentioned earlier, I take heavy use to mean track driving. Most stock brakes with street pads will do this. The problem is heat. You are operating in a temperature range that is above what the stock brake pads were designed for. 2 ways you can solve this:

1) get a big brake kit so that the temperature during such activities are much lower, thus allowing you to use a street pad for high speed driving. Cost: several thousand dollars.

2) Get a set of good race pads (there are several to choose from) that operate effectively at those high temperatures. Cost: ~$150-$250, depending on what you go with. Much cheaper than a brake upgrade, but track pads generally are not suited for street use. So you have to change pads before/after each track school.

 

Cast iron has better friction properties than stainless steel, not thermal properties. The draw back is cast iron rusts, which is why many motorcycle rotors are stainless (because they are in plain view and rust looks bad).

Cross drilling is partly for allowing gas to escape from the pads, but mainly for looks. It also gives cracks a nice place to start. Look at the rotors on something like an IRL car... no holes, just slots. The slots, or grooves really since they don't go all the way through, are for gas escaping and the clean the pad, as stated by someone earlier in the thread. Extra surface area for cooling has nothing to do with it. But the vanes in the middle of the rotor are for cooling.

Often too much heat will boil the brake fluid in the caliper, causing a mushy pedal and loss of braking power. The friction characteristics of the pad can also change with temperature.

Some things to remember when switching pads are cold temperature performance, noise, more brake dust, and more wear on the rotor. Stock pads are typically of a very high quality, but the factory has to take all those factors into account. So other pads are typically going to increase one performance aspect while reducing others.

Carbon composites are another choice for brake rotor and pad material. Usually only seen on racecars though.

Just wanted to get some of the facts right,
Desmo

 

Hey Matt.... I would like to hear some info about Panther Plus or even the XP for the stock brakes on the 350Z.

I will be starting out at the track with the car totally stock... but I want a more aggressive pad for the first two weekends at the track. Are ya'll planning to offer a fitment for the OEM calipers?

Thanks,

PeteH