midpack

iTrader: (3)

That is an awesome offer. What are some benefits of PFC over Hawk that I should consider the switch? What's your pad recommendation for a heavy pig that is the MSM with TSE front and 1.8 rear filed to fit sports? Tires: BFG Rival, ABS: yes. Looking for something that is suitable in both wet and dry conditions. I drive like a girl (slower than spec records) and have never noticed any issues with the DTC 60s in the wet so it's a little concerning to see the recommendations against running 01/11s in the rain.

OGRacing

iTrader: (1)

in one word, consistency.
A hawk dtc 60 has something like 25% change in TQ from 600*-1400*
PFC 01 has a 4% change in Tq from 100* to 1600*

there are plenty of other reasons too. go back and check out the first 3-4 posts I made. one of them covers brake pads.

ThePass

iTrader: (3)

I ran PFC 01's for the first time at Auto Club Speedway last weekend. If there is any track around here that will highlight what Johnny is talking about re: consistency across heat range, this is it - 45 seconds of straight and banked turn (flat out) allowing brakes to cool before braking zone for T3. I've been playing with a set of live IR temp dataloggers on the brakes.. being able to pull up the log and see the numbers on how much they cool on each lap there really drove home to me how important a consistent pad is.

Braking felt the same there at T3 as it did in the hard braking zone of T11 half way through the infield where the brakes are much hotter and up to temp.

This became even more important in the third session as rain began to come down. Unable to put as much heat in the brakes as when it is dry out, rotor temp just before I got on them at T3 was plummeting to sub 400 F. The 01's felt the same every time.

-Ryan

emilio700

iTrader: (3)

Yup. T3 at ACS back in 2004 was what put me on to the importance of that very parameter. Running some old school Wilwood pads, super high metal content. Tried everything Porterfield had and some Hawks (pre DTC) over the next few years. Everything I tried would exhibit these huge shifts in torque and brake bias during that 5-6s long braking event. The worst were dead initially, would ramp up bite then fade right before turn in. Arrgh! Learned about low metal, high ceramic friction materials and have been using them ever since. Became a CT dealer in '07.

OGRacing

iTrader: (1)

talking about Big F'ing brakes. i saw this guy over the weekend...


I had to take spy shots as i made it clear i was a fan boy. but it had massive PFC calipers.


that caliper is literally the size of the mechanic's head.

hi_im_sean

iTrader: (3)

can i get a pad recommendation? yesterday if finished off my parts store pads.

im running 205/50 rivals on 9s but will be going to 225 when these wear. stock 1990 brake system with the exception of NA8 front rotors and abutments. track only car, although it does get driven to and from events, and im known to screw around with it on the streets. motor is stock at the moment, but will be getting boosted in a few months if that matters. the rears have been locking up first most of the time even with the larger na8 fronts.

thanks johnny

OGRacing

iTrader: (1)

ok so for a set up you have 1.8l brakes front, 1.6l brakes rear?

you say the rears lock up first. tell me more about this. does it trail brake? is so when? (coming over a hill, Decreasing radios turn).
Does it just lock the tires in a parking lot, or in the snow. I'll need to know what the car's behavior is when it's locking the rears. i would like to know how the car feels when your entering a turn.

carnut169

I am building a track toy (90% track) with a LFX motor. Best guess at this point is roughly 300hp at the wheels and 1900lbs with driver (no heat/ lights/ glass hood, lighter engine, yada yada). All new bearings bubs etc.

I've got the FM Stage 2 kit:
The kit includes:
Wilwood Dynapro 4-piston calipers
Wilwood Powerlite 4-piston calipers
two-piece 11" slotted Spec-37 front rotors
one-piece 11" slotted rear rotors
stainless braided lines front and rear
FM proportioning valve kit
ATE DOT4 brake fluid

and substituted the Wilwood E compound Polymatrix pads (FM said good for track).

The fronts will be ducted.

I'm wondering about pads (get new now or run the Wilwood until they wear out)?
I'm also wondering about the master. I can run the GM booster pump easily. Or I'd pull the whole thing and do with a dual MC setup or even a single (unboosted?) with the proportioning valve kit if you think that's the way to go.

hi_im_sean

iTrader: (3)

not sure what you mean by trail brake?

it happens in a straight line on level ground coming up to a turn after a long straight. to be honest ive only had it happen when i was running too much pressure in the tires. once i figured that out and dropped a few psi, i wasnt locking them up at all. but i assume when i work up to that point with my new found traction, it will behave the same. sometimes just one rear wheel, sometimes both, and on one occurrence it locked the rears and the pass front. this is all on track. when i dont lock the brakes up it feel great entering a turn. i wont initiate a turn when ive had any wheel lock up until the car feels like it settle again, its caused a few run offs and some very late turns. when it does lock up, i have to compleyely remove my foot from the pedal to get the wheels rotating again. just easing up on the pedal wont do it. i attribute this to awful pad modulation, and possibly calipers that need to be rebuilt.

also the pads seem to be wearing at different rates, so i was planning on rebuilding all the calipers anyway.

camber settings are 3 front, 2.7 rear
0 toe front, 1/16" in rear

on the street with a completely differnt set of mismatched garbage tires, it locks up the fronts consistently

does that help, or am i digging a hole?

i plan on the v8r setup in a year or so, depending on funds. i need a stop gap until then.

edit: i have it on video if youd like me to upload it

OGRacing

iTrader: (1)

Good information, something is broken. the fact that you can't modulate the pedal is alarming. that leads me to think that there is binding in the brakes. that combined with the fact the pads are wearing unevenly.

i would check the calipers to see if the pistons are becoming stuck in the bore.
you can tell this by what pads are wearing faster then the rest.

check your hubs for lateral run-out,
I've covered this before and should be a video somewhere.

check your caliper pins to see if they are worn and in need of replacement.

after you check those out the pads i would recommend on na8 F and na6 rear brakes. would be the 08 compound in the rear (link here)
and the pfc 11 up front ( link here)

i would want to see the 08 out back because it's an endurance pad. You'll need that extra live with the smaller rear rotors. this way you don't have premature pad failure.

OGRacing

iTrader: (1)

carnut169,
Excellent set up. You’re on the right track for a quality car build. Your question is for master cylinders. I like to recommend Dual master cylinder brake pedal assemblies. I calculated out the miata’s braking components, my calculator recommends a .811 F (13/16) and a .087 R(7/8) master cylinders. This will yield a max of 1391.30psi @250lbs of force.

Boosters kill too much feel for a race car.
Single master cylinders are outlawed by some race organizations. The reason why is, if there is a fluid leak you lose all braking. Nasa and Club level of SCCA it is legal to run a single MC, but if you’re going through the trouble why not upgrade to the safer dual MC.


My friends over at enjuku Carry OBP pedal boxes. A few customers have used them and the general consensus is that they are a good piece for the price.
Enjuku Racing Parts, LLC - Advanced Search

OG racing can get you AP Pedal boxes. They do start at $1000. It is the pedal box that most pro teams use.

hi_im_sean

iTrader: (3)

thanks again johnny!

PatCleary

You might want to check the single circuit thing. I'm pretty sure SCCA requires dual circuit braking systems in most classes. I seem to remember coming across that in the ITA rules book and SM I don't believe can touch the brake system.

Thanks for the advice on brake balancing. Once I can tow the car everywhere I'll probably go to an un-boosted setup, but I just installed a prop valve for now. What a painless experience. Any tips on setting it up? I have a data system if it helps.

Someone commented on going with the 949 kit with Dynalite calipers, I'd been kicking around the idea of that kit for the Dynapros, what's the disadvantage?

carnut169

Great, thank you.

I will likely move to a dual Master setup eventually but the unplanned $1000 for a pedal box is an issue right now. Looking at the OBP setup raises further questions: will the masters fit behind the dash (they appear to go back towards the driver in the picture of the universal top mount) and will they be accessible? Will I be able to utilize the GM gas pedal which is a terrible plastic POS but also required with the LFX motor. Lastly, will the bore sizes you calculated work with the Wilwood components as well as the stock Miata stuff?

Being that I'd like proceed with a lower cost option should the stock 93 master work? Run it unboosted? Just cap off the line? Is there a better short-term solution?

Last question in this post: I had thought about ditching the hard lines and running -3 lines (easier to route the bias adjuster was one reason). I did some reading and EVERYTHING I could find said this would give me a mushy brake pedal. However, it's just not my experience. I ran a Van Diemen FC, a F1000 and later a Mygale Fc and all had -3 lines exclusively (with aluminum AP calipers and dual masters). The brake pedals were as hard as a rock and felt amazing. I'd love to reproduce that feel in the Miata.

I appreciate the time your putting into educating all of us!

OGRacing

iTrader: (1)

The OBX comes in different combinations. The picture listed is for rear facing, floor mounted pedals. So your feet would sit above the mc. They do have hanging MC and everything else in between. It will take some fabrication to get any of them installed. For the gm pedal you might want to opt for the obx brake and clutch pedals only. Use the gm pedal as a hanging pedal. The choices are endless. Take a walk over to enjuku’s sight.

Removing the booster by plugging it is not recommended. I think we covered this before in a previous post on page 14. I’ve seen people run braded stainless lines threw out a car. It can be done but they are 1 heavy, and 2 expensive. I bought a an flaring tool, and the earls -3 caps, I order my SS lines from stockcarsteel.com .

ofspunk7

For my application there was not a requirement to upgrade to the Dynapros. I had asked Emilio about it via email because I had planned to dish out the extra funds for a level up in caliper. Long story short, there wasn't going to be a benefit for me to swap from a 4 piston to a 6 piston with an 11" kit and my setup/car usage. My car is street with a few track days during the summer. I have a lot of seat time to log before I even get close to pushing the limits of my setup. If I end up swapping wheels and moving to a 11.75" setup I may revisit this question. However, for now they said I didn't require this upgrade. So I ordered the Dynalites. I trust the 949 team.

OGRacing

iTrader: (1)

Correct. the amount of pistons has 0 to do with the braking performance. in fact the more pistons you have the less consistent the line pressure becomes at each piston. it's better to spend the $$ on larger rotors then more pistons. as a larger rotor increases life of braking components and increases tq.

PatCleary

Ok, I assumed the Dynapro's were stiffer and thus less prone to taper and more consistent performance. Outside of possibly brake balance my existing brakes are better than I am, I'm primarily interested in cheaper consumables and pads that won't taper.

OGRacing

iTrader: (1)

the dynapro with a bridge bolt will be stiffer. Any caliper that is in 2 piece construction is only as stiff as the bolts holding it together. assuming that the dynapro and dynalight use the same hardware, they will both be the same strength.

bbundy

Dnipro Radial uses bigger bolts than dynapro lug or Dynalight. Plus the bolt spacing is different it wraps further around the rotor. The design is closer to a Superlight.

Dynapro lug is not like the Dynapro radial. They are completely different beyond just the mount orientation.