sbcrx007

iTrader: (1)

I'm still running the 1.6L brakes on my 93 track car. Stoptech street performance pads front, wearever junk pads in the back. Budget does not allow for 1000 brake kit, and 300 in pads. There's enough pad to lock the front tires (somewhat sticky bfg Rivals), and brakes don't fade on my home track (Nelson Ledges - pretty easy on brakes). So I don't see much reason to go to bigger rotors or calipers, unless I'm missing something? Longer pad life? Yes, bigger = more brake torque, but I can already lock the tires (no ABS), so that is limiting factor. R compounds in the future, possibly, so that may change. Bigger rotor will soak up more heat, but not having heat problems yet.

1. I've read all the hoo-ha about how much better 1.8L brakes are etc etc, and all the stuff about the 1.6L parts being lighter and thus less unsprung weight. Which is faster on a turbo miata?

2. Brake balance is currently front biased, due to more aggressive front pads and stock proportioning valve. I'm due for pads and will be, most likely, going to the Stoptech pads all around. Would going to 1.8 brakes rear only balance things out better?

3. If I'm able to lock the tires and aren't experiencing fade, is there any other advantage to running Hawk or Carbotech compounds?

Anything else I'm missing? I thought I'd be overpowering the brakes at this point, maybe I'm not using them hard enough... No hose ducting yet either, but will be added this winter.

Braineack

iTrader: (62)

yeah, having a setup where all four wheels help stop is always nice.

sbcrx007

iTrader: (1)

Indeed Scott, indeed...

I had actually left the rear with the junk pads on purpose after reading somewhere else that there would be too much rear bias without an aftermarket adjustable rear valve! Must have been the other forum...

Edit - I just saw that mashed potatoes bit... Dare to be stupid!

jandjracing_58

One thing I did to my 90 Miata track car that gave really good results was installing a 2002 Miata LS sport package braking system front and rear. Hawk blue compound and stainless lines.

I don't have any exaggerations to go with this, it just allowed me to threshold brake through an entire race at VIR with no brake fade.

sbcrx007

iTrader: (1)

Thanks Jeff, I've been looking into doing something similar - I assume you mean the larger master cylinder & booster as well? There's a long thread on m.net that I had gone thru.

Did you track the same pads previously on the 90's original 1.6 brakes and experience fade? I'm looking for an apples to apples comparison, hard to get because everyone seems to go upgrade pad compounds when upgrading the 1.8 brakes, so you don't know how much the larger rotors helped.

Also it's my understanding that you can just go to 1.8 rotors and brackets and reuse your 1.6 calipers with 1,8 pads, and get larger area pads as well. I could see that being an advantage to pad life.

jandjracing_58

for the brakes I used the 02 sport calipers, brackets , pads front and rear. I maintained my OE 1990 master cylinder and brake booster.

Yes when I had my original 1990 brakes with slotted rotors and Hawk blue pads, approximately 15 minutes into any track session or race I would lose threshold braking. I'd find myself hitting the pedal a full 100yds sooner just so I wouldn't run off track. When running down the top 3 guys that loss of braking hurts

sbcrx007

iTrader: (1)

Thank you Jeff, that is good apples to apples info. I'm typically running 20-30 minute sessions, so it sounds like going to the larger oem brakes would be worthwhile.

Savington

iTrader: (31)

It's possible to make the stock brakes work, but it's not fun. Rover in full PTE trim ran the tiny stock 1.6 rotors and calipers front/rear as required by rules. No limits on the rest of the parts, so I ran NB Sport 15/16" master, NB non-ABS booster, Trackspeed Wilwood prop valve kit, Hawk DTC-60 pads front/rear. The pedal felt like ****, but it was consistently shitty and never really affected the stopping distance of the car. It was fine at most tracks, but it did require that I run high-dollar fluid (Castrol SRF) at Laguna Seca to maintain pedal feel through 30+ minute races.

I've since switched to 1.8 brakes and the pedal feel is better, but not fantastic. The Sport fronts in Thumper are significantly better. Next time Rover needs brakes, I may throw our 11.75" Wilwoods back under it. Nothing touches the pedal feel of the 11.75s.

sbcrx007

iTrader: (1)

Thanks Savington, didn't realize the sport brakes were such a big improvement. No doubt the Wilwoods are even better, although that's a massive rotor for a 2k lb car. Do the pads last longer on track vs the 1.6 setup, given the larger pad area & larger rotor swept radius? (I also need to do a bit more reading and verify the sports will clear an OEM NB 5 spoke wheel.)

I guess what I meant earlier with post #1 was that Yes - you can put on a big brake kit, go to Corrado rotors or similar, etc, etc... But isn't there a point of diminishing returns, bigger rotors/calipers being heavier and heavier?

If the car stops and you can lock the wheels if you press hard enough, the brakes don't fade after 30 mins of hard running, and the proportioning f/r is well sorted... what's to be gained by going to larger brakes?
Just a pedal that feels better?

jandjracing_58

It's worth it to try and evaluate the difference for yourself. As a driver my style differs from your, just as yours does from Mr. Savingtons.

My style with 02 sport brake feels perfect, and with 1.6 felt shatty.

hornetball

iTrader: (4)

The Wilwood BBKs typically drop unsprung and rotating weight because:
1. Aluminum hats with separate rotor vs. 1-piece cast rotor.
2. Aluminum fixed caliper vs. iron floating caliper

Besides weight, main advantage is lower maintance. The OEM calipers will taper your pads like crazy. You can get a lot more track days between brake jobs with the BBKs.

sbcrx007

iTrader: (1)

Jeff, agreed different strokes for different folks. I'm not in your or Savington's league though, you guys have more experience to know what works and what doesn't. And what is fastest, given the available parts. Thank you both for the first hand recommendations.

Hornetball, yeah I get that much, but this is just trackday fun on a budget. Unsprung weight and rotating mass were my reasons for not upgrading to 1.8L brake parts.

Brake pad taper is actually something I keep meaning to measure - never noticed any obvious tapering, but that was just by eye. What sort of thickness differential is expected, and how much is too much?

After another few hours of reading, it sounds like NA folks are running the standard 1.8 bits up front and running the sport 1.8 bits in the rear to get a better bias, with either the NA or NB master/booster...

As with everything else, this is another rabbit hole to fall deeper and deeper down into...

hornetball

iTrader: (4)

No need to measure it. When you start hitting the brakes often and hard it'll happen and be obvious to the naked eye. It's just a property of floating calipers.

It's not too much of a problem by itself. It's just that the uneven wear shortens pad life. Just keep an eye on them and replace the pads when the wear slot goes away. That's all I do on the Silver car. Frequent brake jobs and I've found a less expensive pad that works for me on that car.

The Red car has the 11" BBK up front and the extra life you get is noticeable and welcome. Pads wear even and you can let them go much longer. But the pads are more expensive, so . . . .

You're right, quit obsessing about it and go hit the track. You'll soon find what you need to upgrade. LOL.

sbcrx007

iTrader: (1)

Yeah, that's what I've been doing. I've been waiting to replace the pads til I figure out what I'm doing with the rest of the brakes, so I'll be curious to see how bad they are tapered...
Out of curiosity, what pads do you run on the silver car?

So, here are the options for my 93 using off the shelf miata parts:

1. Upgrade to standard 1.8 rotors/brackets/pads in rear only, thereby improving overall brake balance, and going to adjustable proportioning valve

2. Upgrade to standard 1.8 brakes front and rear, thereby improving heat absorption/shedding, more pad area (and possibly longer life), and higher possible brake torque. Adjustable proportioning valve also, but will probably be full open.

3. Upgrade to standard 1.8 brakes in the front, upgrade to sport 1.8 brakes in the rear, thereby improving overall brake balance, more pad area (and possibly longer life), and higher possible brake torque, and going to adjustable proportioning valve

4. Upgrade to sport 1.8 brakes front and rear, thereby improving heat absorbtion/shedding, more pad area (and possibly longer life), and higher possible brake torque. Adjustable proportioning valve also, but will probably be full open.

Other options:
Could also go to the larger/later NB master cylinder (15/16) for a harder pedal w/ less stroke to actuate, or even the 1" 929 master.
Could also mix and match brake boosters for more line pressure, though it looks like the NA master and booster don't mix with the NB master and booster.
master/booster thread reference:
Some interesting brake information (tech!) - MX-5 Miata Forum


I'm leaning towards option# 3 or 4, and considering going to the NB master and higher ratio single diaphragm booster
Edit: This is assuming running same type pad front/rear, bias taken care of by brake hardware/adj. proportioning valve.

Leafy

iTrader: (1)

I think you've been reading too much auto-x braking threads. Track guys dont seem to want nearly as much rear bias as auto-x people.

curly

iTrader: (25)

Just fixing a little error from post #5, with the 1.8 brackets and rotors with 1.6 calipers, you still use 1.8 pads, NOT 1.6.

Again, the larger 1.8 pads fit in the 1.6 calipers.

sbcrx007

iTrader: (1)

Leafy - yeah, possibly...

Curly - thanks, fixed!

johnny@OGracing.com

OGRacing

iTrader: (1)

you seem to have your mind in a jumble when it comes to figuring out what system you need/works best. Without diving in to too-much boring information i will say this. the only way you can change TQ on a braking system is

1 Rotor diameter
2 pad compound
3 hydraulic advantage.

Remember the Goal isn't to get the maximum amount of TQ. The goal is to have a balanced system (front to rear) without overloading the tires. If you're racing on 195mm falkens your requirements are going to be drastically different than someone running 225 slicks.

sbcrx007

iTrader: (1)

It probably does look jumbled, collectively. But its not confusing, everything is pretty straightforward.
There's also
4. booster ratio, which multiplies your hydraulic advantage
5. tire compound & width, as you alluded to

That's why I'm asking, plenty of folks are running on the same rubber (205 rivals) as me with similar suspension and power. Which combination of parts from post# 14 yields the fastest (and best balanced) car?