sixshooter

iTrader: (12)

This is the kit that lets you move the standard NA8 calipers out so you can fit larger sport rotors in the rear:


Miata M-Tuned Big Rotor Kit
Use that^ in the rear and the 11.75 kit in the front and you will be pretty good.
SuperMiata 11.75 BBK

11.75" vs 11" Corrado pictured:


Sexytime

OGRacing

iTrader: (1)

after you burn off that rotor it's recommended to switch to a PFC 11.75" rotor. The rotors on my car have been in service since 2012. same rotors, 500hp, 15 events a year, 2700lbs with driver.

emilio700

iTrader: (3)

Depends on whether one chooses the $35 econo special Wilwood or $89 11.75 SPM left and right directional vaned rotors.

sixshooter

iTrader: (12)

This is another reason I like the 11.75/Dynalite combo. There are a bunch of different rotor designs and brands and there are pads from nearly every manufacturer to choose from. And some choices are quite cheap and some are super fancy.

sixshooter

iTrader: (12)

They even make ones that look like this:





Not that you need one like that, but they do make them.

OGRacing

iTrader: (1)

i was looking at those rotors. One thing to keep in mind is that we are playing with circle track rotors here.

Dirt late model cars install a fluid shut off valve in line for the front right brake caliper. essentially only 3 of the brakes are working. They do this to help rotate the car in dirt. many of the rotors on sale today are meant to only be there because the rules for dirt late models said they needed to have 4 rotors and 4 calipers. a word of warning. there are rotors and calipers for sale that their only job is to exist, and are not meant to be used.

Dirt Late Model Brake Shut Off Photo 2

sixshooter

iTrader: (12)

Yes, they say online that they are for lightweight cars (less area).

OGRacing

iTrader: (1)

I'm incited by them too. they look cool. but my inner engineer says run!

wilwood's sight says "light dirt use" it also says "unsafe for street".


Wilwood High-Performance Disc Brakes - Rotor No: 160-8135

ThePass

iTrader: (3)

I'd wager that the 11" Good-Win rotor (made by DBA) would outlast the standard Wilwood 11.75" 'HD' rotor by a large margin. Because drastic difference in iron composition and vane design.

-Ryan

OGRacing

iTrader: (1)

your absolutely right. i was looking at the 11" rotor vs 11.75" rotor both offered by wilwood. all of wilwoods rotors come from china and have terrible life vs. cost ratios.

sixshooter

iTrader: (12)

Apples oranges

11" premium rotor vs. 11.75 economy rotor 11" premium rotor vs. 11.75 premium rotor

FWIW, my 11.75 Wilwood "economy" rotors are holding up very well. Two sets of pads and they still look great.

ThePass

iTrader: (3)

Yes.. That was my point though. Earlier comments alluded to rotor diameter equaling greater lifespan. Certainly true, all else being equal, but I'm pointing out that rotor composition and design can trump size in that arena. Cheap larger rotor still lasts shorter than smaller high-quality rotor.

FWIW, many of the guys on the DBA rotors still haven't needed to get a replacement set after 4+ years.

-Ryan

PatCleary

First, thank you for the information, it's been an interesting read. I also like that there's been no implications that bigger brakes will make a car that can lock them up brake faster.

At Laguna Seca last weekend I was getting wheel lock up going into 2 and 5 under hard braking. I know that this means that I need a lighter touch on the brakes. I also want to investigate shifting some brake balance backwards, as it sounds like there's performance there. Obviously the easy way out is the FM prop valve, but it sounds like a real MC setup is the right way to go.

I only drive the car to the track and on the track, but that does involve driving through SF for trips to Laguna Seca. Obviously it will take more effort. Am I going to hate myself? Or once I put a new hole in the pedal will it be reasonable? Would capping the vacuum line to the booster be a good approximation to try it before I start disassembling the brake system?

OGRacing

iTrader: (1)

Dual master cylinders are the way to go for a “track car only”. A booster system should be kept if the car drives on the street. The reason for that is the dual MC can be annoying in traffic. A booster will multiply the line pressure x4-9. In stop and go traffic this extra force helps a .3mu street pad work. A Dual Mc system will take more pedal force to create the same line pressure. The down side to this is, it kills a braking feel. The Dual master cylinders systems are inherently faster to respond.

Pulling the vacuum on a booster system will not give you the same response. The pedal rations on a booster system are 4:1, a manual system is near 6:1. Plus the manual systems will be using much smaller MC’s.

PatCleary

The whole car is annoying to drive anywhere besides the track. Sounds like if I cap the vacuum system it will be representative of the worst case scenario. And if I can live with that an once or twice a month I'll be fine?

OGRacing

iTrader: (1)

It really won't give you an accurate representation. if you want to try your experiment keep this in mind.
A boosted miata brake set up (4:1 pedal ratio, 4.71 boost ratio, .874" mc) at 100lbs of force will yield 1580psi. Remove the vacuum off the system and your psi @ 100 lbs will tumble to 330psi.

A dual MC unit (.57" Front, .811" rear Mc's, 5.75 pedal ratio) @ 100psi will generate line pressure near 750 psi. double the psi of a vacuum less boosted system.

ofspunk7

Thanks everyone in this thread for the info. I think I have decided on the following route.

Flyin` Miata Stage 1 four-wheel big brake kit
The kit includes:
Wilwood Dynapro 4-piston calipers and Wilwood BP-10 pads front
Porterfield R4-S rear brake pads
two-piece 11" slotted Spec-37 front rotors
one-piece 11" slotted rear rotors
stainless braided lines front and rear
FM proportioning valve kit (not on 2001-05 ABS kits)
ATE DOT4 brake fluid

My rear calipers are in amazing shape. I won't know how the rubber on them looks until I pull them off, however the outside is very clean. If the rubber looks aged, I will rebuild them. If it still looks healthy I will just clean the outside, toss some black on them and call it a day.

I need to replace my master and brake booster as well. The current plan is to buy a new OEM master from Rosenthal Miata (or planet miata if they get back to me). I figure it is worth it to pick up a new master with new seals. Then pick up a used brake booster. I still have to check my local used places, part outs and maybe ebay (or planet miata if they get back to me).

Thanks for answering my questions.

sixshooter

iTrader: (12)

The BP-10s are worthless for anything but the street. I vaporized a set down to the backing plates within 20 laps. Make another selection.

ofspunk7

Yeah I will use them only for street. I will have track dedicated pads. That is how I ran my subie and that is how I plan to run my Miata.

emilio700

iTrader: (3)

You must have missed half of the important stuff..

As sixshooter mentioned, the BP-10's are show car pads. The HPS + is an HPDE pad for street tires and stock power, and not good ones at that. You need race pads, plain and simple. OG Racing, FM, us (949 Racing), Goodwin, Trackspeed can help you there. Your front plate number is 7812, rear is 458. If you intend on driving this 350whp track car anywhere in the vicinity of its limits, you must not run the pads you listed.

You have too much rear rotor for the front rotors chosen. Either step up to 11.75 (what I would recommend), or step the rear down to 9.9" NA8 rears. Running 11's front and rear with your piston areas will be very frustrating for an experienced driver running near the cars limit. This is not a guess. We have quite a bit of experience matching these. To make the rotor combo you have balance, you will need almost a 20% difference in .mu between front and rear compound. We find that with that much difference, the torque vs/ temp plots have few points that rise in a linear fashion with the other. Meaning your brake bias will change during braking events even when one compound is in its sweet spot. Bring that delta down by running say, DTC60/DTC70 or XP12/XP10 and you have plots that more closely mirror each other.

As it stands, your brakes will fade after about one lap and have massive rear brake bias that you can't dial out. The .mu on the BP-10 is something like .38. That's comically wrong for your usage. If you insist on sticking with the hardware you have, at least get pads that will cover up the imbalance. FM, bless their hearts, still offers Wilwood compounds. Cutting edge in 1978. Not so much now. Look for ceramic kevlar formulations like PFC, Carbotech, Cobalt, Carbon Lorraine. I'm not a huge fan of Hawks but there are many hear that have like them. Their DTC line is sort of a budget version of the Carbotech / PFC/ Cobalt Cer-Kev stuff.

The basic brake hardware you have is top flight, just not configured well for your usage.