Need Help Deciding on Brakes

[Cephas]

Hey all, Been reading/searching etc, but I can't seem to find clear direction...

89 325is sitting on BBS RX's (16").

The car is going to be used for AutoX and some track days, but mostly it's my Sunday cruiser.

It's time for a brake refresh. I'm going to be bleeding the system with Super Blue (unless there's something better that's recommended) and replacing all the stock rubber lines with stainless.

I've been researching the options for a rotor upgrade. From what I can gather, people seem to love the Rx-7 calipers/rotors, but they are not likely to fit under my wheels - can anyone tell me otherwise? From there I was looking into the advantages of cross-drilled/slotted and have read that they don't offer much advantage over stock. I'm really looking for solid advice on this. If I'm on the track, I want as little fade as possible and it would seem that these should perform much better than stock.

Long term plan for the car is to turbo or S5x, so I'd be willing to take on some added expense at this point to do it right for that day. So take that into consideration (if the Willwoods fit my wheels, I'd entertain buying them now).

So, I'm wondering if there's any real world advantage to buying the slotted/cross-drilled, or if I should just refresh the whole system with stock and be done with it.

[jlevie]

The holes in cross drilled rotors reduce swept area and thermal mass, which reduces braking performance. And the holes are stress concentrators which causes cracking. Think of the holes as initial cracks of large radius. Most modern pads don't need slots for gas relief, so slotted rotors are just an unnecessary expense. I've seen enough failures of SS lines to no longer be a fan of those. The OE lines (in good condition) are less likely to fail and work just as well. There are good SS lines available (Bimmerworld is a good source) but they are pricey and even then the lines will occasionally pull out of the end fittings. I have never seen that happen with the OE lines.

The stock braking system, when coupled with pads appropriate to the way the car is being driven are more than adequate for a stock engine. Bigger brakes, for greater thermal mass, would be appropriate with at S50/52 power levels on a road course. In either case, cooling ducts for the front rotors is advisable for track duty. I don't use ATE Super blue as it can stain the reservoir and make level checks difficult. ATE Type 200 is the same fluid without the dye and what I use on the race car. On a pure street car I'll use Valvoline Synthetic DOT 3/4 as it has a driy boiling point almost as good as the ATE fluid and is about half the cost.

What is just as important is the calipers being in good condition. A car that see's much track time should get caliper rebuilds every second of third year.

For street or AutoX a high performance street pad is appropriate. On the track you need race pads, period. Hawk HPS or the new StopTech high performance street pads are my choices. On track, PFC01 or PFC08 pads.

[Earendil]

Unless you are running a more powerful engine, or weigh a frick ton more than stock, than a halfway ventilated stock setup with real track/race pads will be more than enough for most tracks. both the Pro3 and SpecE30 race groups run stock rotors and on the tracks they run at don't have a big rotor problem, and they are hitting speeds that most stock E30s won't see.

I can't speak though for the best AutoX setup. I know that they have issues with not getting enough heat into the brake system. Stock might help here?

Anecdotally I've heard that drilled rotors eat brake pads faster. Not sure how true that is, or if it's just the driving style of those that choose those rotors.

[nrubenstein]

Don't bother with anything other than pads until and unless you actually are serious about tracking the car with lots of extra power.

A worthwhile brake upgrade will approach the value of the car. Doing just the front is not doing it right. Also, remember that big brakes add weight. For cone packing, you want the smaller brakes you can get away with.

[Earendil]

Don't bother with anything other than pads until and unless you actually are serious about tracking the car with lots of extra power.

I think you would agree that while the "upgrading" may not be needed, one should make sure all their brake components are looking/acting solid before going out on the track, including making sure your potentially 25 y.o. Brakes lines aren't about to disintegrate. "not upgrading" doesn't mean that rebuilding/replacing with stock components won't be an improvement :)

[DaButt]

OP, I'm in the midst of planning/sourcing a brake overhaul.

TONS of searching and question asking led me to believe that for a stock/street/light Autox car the best set up is:

Brembo plain/blank discs
A pad suited for your activity
rebuilt calipers
new brake hoses (RUBBER- NOT stainless steel- there's a whole thread in here on why the SS lines blow dicks)

and if you're really serious a new master cylinder.

I know all I need is street stuff, so I'll be going Brembo blanks, modest pads, hoses and rebuilt calipers. Total- maybe $250.

FWIW. I'm not a guru, but jLevie is, and he'll tell you all day long to stick with stock/OEM bits.

For the kind of driving you say you're doing, I recommend staying modest with your expenditures, especially with a stock motor.

[Cephas]

Thanks for the tips guys. I really appreciate the insight especially about the stainless lines - wow, would've never thought they could be less safe than stock...and the alternative to the Super Blue - thanks for saving that pain in my ass!

A few more questions:

1) Where's the best place to get the stock Brembos and the street/race pads?
2) How much dust can I expect from the Hawks or the StopTech pads?

[Earendil]

Thanks for the tips guys. I really appreciate the insight especially about the stainless lines - wow, would've never thought they could be less safe than stock...and the alternative to the Super Blue - thanks for saving that pain in my ass!

A few more questions:

1) Where's the best place to get the stock Brembos and the street/race pads?
2) How much dust can I expect from the Hawks or the StopTech pads?

Almost every high temp brake pad is going to drop dust like an aggressive fairy. The solution is to run black wheels, which hides it pretty well. Alternatively you can just not care that your wheels always have a brown/grey coat of powder on them.