Savington

iTrader: (31)

If you actually use the car on the street, the Wilwoods don't make much sense. The weight savings are there but the lack of an e-brake function is a big deal for a street car. Use Sport rears or 1.8 calipers on an adapter bracket. For a race car that's looking for every pound, pull the e-brake cables and switch to Wilwoods. There's a group of guys in the middle who autocross and need an e-brake for legality, and for those guys, the e-brake Wilwoods make sense. I won't lose sleep over not selling those kits, though. Our goal was a niche kit that was the lightest possible rear brake setup (hence our decision to do 1.8 rotors and not Sport rotors), and e-brake functionality was never in the cards.

Still working on ours (sorry for not returning those emails, Buddy). Other projects have gotten in the way but it's still happening. Our proprietary 2-piece rotors will shave another ~1.5lbs total, reduce heat transfer to the hub, and work with FM's kit (for those of you who couldn't wait).

Seefo

iTrader: (5)

Pretty sure NASA PT/TT rules don't require parking brakes (under no-points modifications: http://www.nasaproracing.com/rules/time_trial_rules.pdf) . I know spec e30s don't either. NASA autocross X class allows parking brake removal, etc.

Not too far fetched not to have an e-brake on a track only car.

Leafy

iTrader: (1)

Weird. Its one of those rules the insurance companies would require, even if it would be a tad silly to think you could save your *** with just the e-brake on a track in the event of a primary brake failure.

Keith@FM

iTrader: (1)

The most direct comparision we have to the "Version 4" BBK from Goodwin is our Stage 1 kit with the proportioning valve deleted. Of course, I think you should run the prop valve as that'll make a bigger difference to your braking than anything else. We use the Wilwood Spec 37 rotors in front, which I think are as good as anything else on the market.

The FM kit with a deleted prop valve would be $945, which is $650 less than the Goodwin kit. If you want the prop valve, it's $995. So I'm not seeing the "lower price". For the price of the Goodwin kit, I can hook you up with rear Wilwoods and 6 piston front Dynapros.

The Wilwood rears add more bite in the back with a larger piston area and have a larger pad. They're a good upgrade. The stiff calipers help contribute to a really nice pedal feel, and the bigger pistons mean you can actually get some rear bias.

On my track car, I find the parking brake most useful when I'm loading on the trailer. I'd never expect a parking brake to be helpful on the track in the case of a failure. Ever tried to stop a car at speed using the parking brake? It's entertaining and educational and ineffective.

Back to the original question - as noted, a firm pedal but no stop is usually pads. I'm assuming you only hit 110 mph at one point on this track, so it could be a matter of cooking everything in the turns before that point. It might be worth doing a straight line test with cool brakes, and to check the booster you could also lift off a little bit before you hit the brakes to ensure you've got vacuum. As Savington noted, make sure that check valve is in the line to the booster.

bbundy

No brakes after long sustained on boost straightaway is either overheated pads or your check valve is leaking and you are getting boost instead of vacuum in your power brake booster.

One of the reasons I would like to design a system without a vacuum booster. More consistent pedal effort in not relying on a constant vacuum charge in the booster.

.

Leafy

iTrader: (1)

You're giving me bad thoughts about making a bracket and adapter to run 2 wilwood masters and a balance bar in the stock location rather than putting the new booster and master setup I have. Dammit, I already know what the setup will look like, and how much more awesome it will be. Dammit.

mrjones2

iTrader: (1)

I would fix the problem 1st before throwing $$ at it. spec miatas hit 119mph at Road america & they are heavy and use stock brakes. FP / EP miatas are lighter / faster & use stock brakes. The FP miatas are over 130 mph and they use the dinky 1.6 brakes.

racers may bitch about them, but I've never heard about a complete failure under race conditions (and I'm talking about NA cars with less than 200 hp). It would be a safety issue and then no one would run them. Big power, then yeah beef it up

I suspect your pads are glazed. I had a similar situation on a PTB MSM (on stock sport brakes) - turns out the customer bedded them in during a rain race and then wondered why the car wouldn't stop. Pad surface was mirror finish.

Kendall

bbundy

Most of the well preped EP/FP miatas I have seen don't use a booster. Better more consistant brake feel. They also dont need to scrub near as much speed to enter a turn compared to the small amount faster they are top speed than your typical HPDE car so caliper and rotor size dosn't need to be increased. The method they use to go faster is to not use as much brake rather than just add more power for the straight.

mrjones2

iTrader: (1)

just trying to make a point (the stock brakes are not **** & you dont need to spend thousands of dollars or you die) - and I'm sure the FP guys would go to bigger brakes if they could, but that's the class equalizer. OP needs to fix his brakes before chucking $$ at it (especially if its in the check valve / MC area). Still there are cars (2400# spec miatas on DOT tires with no brake cooling) that make the stock brakes work.

KJ

Seefo

iTrader: (5)

The issue isn't so much about weight, as it is about speed. 110mph isn't significant in that its not beyond a stock miata. In this case, I agree the OP needs to sort out why he is losing brakes at a specific speed (which it seems the suggestion for the check value is pretty close), but I don't think its a bad idea for him to upgrade his brakes. an FMII turbo car is a whole other beast compared to a spec miata or even a mazdaspeed.

The only thing I think you are missing is that weight is not as big a factor in braking as speed. Maybe you are not, but you seem very focused on the heavier miatas as justification that the stock brakes work (and work well), but that rule doesn't apply the same way when you are running 100+hp more. Just keep in mind that velocity is squared in the kinetic energy equation, while weight is not.

EO2K

iTrader: (37)

100+hp over stock, and 2300-2500lbs in street trim.

mrjones2

iTrader: (1)

I aint arguing, just trying to help. The MSM I built was at the very top of the PTB points system & couldn't take the points for brakes - it was my job to make them work. sport brakes, ducted, with a manual prop valve worked excellent on 2350# car with almost 300 ft-lb of torque (unless the pads are glazed).

It being nasa, we tuned it with an effective torque curve to be under the max HP limit for the power / weight - but have a **** ton of torque everywhere else (and it was very much 100+ HP over stock). Maps looked crazy maximizing the area under the curve. Customer spent tens of thousand of dollars to make the car fit in the rules.

Anyway, blah blah thread jack. I'm not against big brake kits, but a car going 110 mph probably doesn't need them.

Scrappy Jack

iTrader: (2)

<-- Has a massive BBK on a car with 100 WHP.

mr_hyde

iTrader: (4)

OP, fix the acute problem with your current system and then make a new thread discussing BBK options. [/thread]

Leafy

iTrader: (1)

Fixed.

z31maniac

Me too.

Wilwoods on all 4 corners.