JasonC SBB

To the OP: Why did you discount FM's "little BBK" with TSE ducting?

In my experience ducting makes a massive difference.

hustler

iTrader: (6)

It matters with ceramic pads, no with "metal" pads.

hustler

iTrader: (6)

That sure looks like a Wilwood caliper.

Scrappy Jack

iTrader: (2)

I guess that comes down to whether or not the Powerlite caliper alleviates the pad taper issues? Flyin' Miata seem to go to some length to note that the setup is really geared for autocross and street applications versus track stuff.

However, for "light" track duty (infrequent events with intermediate drivers and low HP cars) it might be a viable option?

Rallas

iTrader: (9)

I looked at the FM little brake kit, but wanted the full 11" rotor size and if I remeber correctly the 7112 pads for the Forged Dynalites are cheaper than the Powerlite pads, don't quote me on that one. The Powerlites also have slightly less pad volume (would wear out quicker). I am making all the brackets myself so there would be very little difference between upgrading to a a sport front or a 11" miata rotor.

My main goal is the cheapest cost (for quality parts) and consumables cost for a very reliable dual purpose brake setup that fits under OEM 15" wheels.

Rallas

iTrader: (9)

I got the calipers, pads, lines and rotors in today. A quick mock-up with an old hub confirmed that the caliper will clear the NB 15" wheels, 2 maybe 3mm (just less than 1/8") clearance between the caliper and the wheel. I had an older 96 M edition 15" wheel laying around from my dad and checked it, doesn't look like it will work without at least a 5mm wheel spacer. I have another old Crager 15" set in the crawl space I want to check, I am pretty sure it will not work because it only clears the factory caliper by 1/4".

I am starting a 6 week night shift run at work tomorrow and hope to get some pictures taken of the mock-up before I leave today. I also went by the local metal supplier and got lucky with a ton of 3/4" cut off aluminum for dirt cheap. Now I just need to find the time to make some chips and get the brackets done.

I am going to fab up some brake ducts/shields while I do all this. Is there a reasone why the TSE or other duct kits for the miata only use 2" ducting? I can get some 3" for dirt cheap, but have not had a chance to see if there will be any intereference issues with 3" ducting. I am assumming that 2" is used to to packaging constraints around the hubs and suspension?

Rallas

iTrader: (9)

It looks like the thicker (22mm) Mini rotor fits the 120-6806 caliper and pads with 1. 5mm to spare. You would not be able to fit any backing shims in there but the shims aren't need for track so it will work.

The rotor holes for the Mini lugs are 16mm diameter where the Miata holes are only 13mm. Do i need to make spacers for the lugs as well as the centering ring or will the clamping force between the wheel and hub keep the rotor from moving? I hope this makes sense.

curly

iTrader: (25)

Just the centering spacers are used. I always assumed the slack in the lug holes would be taken up after the first hard braking, then it'll stay there. If it makes you feel better, reach in and rotate the rotor clockwise before torquing the wheels.

Rallas

iTrader: (9)

That is what I was thinking too. There is no way that rotor is moving with 4 lugs torqued to 80-90ft-lb clamping it all together.

sixshooter

iTrader: (12)

The hub rings from your Corrado kit don't work with it?

Rallas

iTrader: (9)

I didn't think to try the Corrado centering rings. The Mini rotor center ID is 65mm, the Corrado's are 64mm, close enough (Miata is 55mm). For some reason I cannot find my Corrado bracket set even after spending half of Saturday cleaning out my garage. I picked up some aluminum round stock to make centering rings from and should have the fist set made tomorrow.

Ski_Lover

With all due respect to FM, TSE, 949 and other reputable brake vendors, I find it hard to swallow needing anything other than stock brakes (size) for an NA motor and a 2200 lb car. Consider that F-Production Miatas run 1.6 stock calipers and rotors @ ~ 140 whp. E-Production Miatas run 1.8 stock brakes @ 185+ HP. The brakes are good enough to lock up soft race slicks on a car that will see over 135 mph track speeds and paces about 10 seconds a lap faster than wreck pinata, I mean spec miata.

Granted longevity vs. heat dissipation IS an issue, but I prefer to run $20 solid stock rotors an $70 track pads. I decided to go with the LBB (Wilwood Powerlite) calipers and TSE prawns for my DP AutoX / Trackday car. I have little concern that this smallish caliper with my stock 1.8 rotors will be just fine for my ~140 whp car on the track. Its a Miata for crying out loud, if you have to park it, you're doing it wrong.

Rallas

iTrader: (9)

It has been a real slow first night shift at work so I did some calculations to convince myself that the 11” rotor are not a waste of time.

When you look at the change in the area swept by the same size pad it appears that the actual increase in area/torque is very little when going from an 11” to 11.75 rotor. Again, I realize that the big buys need every bit they can get.

Going from 11" to 11.75” rotor results in 6.85% larger diameter, 12.3% larger overall area but only 7% bigger pad area. Pad area is calculated here as the “swept radius” of the pad. I will measure the pads when I get to the house, but based on Wilwood docs I guestimated 2” and a ± 1/4" wont change the results much. These geometric ratios would indicate 6.58% more brake torque for the same applied piston pressure and 7% more rotor area for the pad to do its job in and dissipate heat into = less wear. I know there is more to the thermal mass part, maybe if I am bored tomorrow night I will attempt that one. The pads also last a hell of a lot longer if you don't overheat them.

These numbers support my initial guesses that there really is not a big change between going from a proper (non Corrado crappy vented) 11” rotor to a proper 11.75” rotor. I am sure the Wilwood friction rings work better even though they have less metal (thermal mass) in them, I will have to do research on that one too.

Just for giggles I did the same calculations to see what the changes are for the standard upgrade paths from 1.6>1.8>11”>11.75” rotors up front. Again, I am assuming the same pad area/section.

Going from 10.07" (1.8 brakes) to 11" rotors results in 9.2% larger diameter, 19.3% larger area, but only 10.3% bigger pad area.

Going from 9.25" (1.6 brakes) to 10.07" (1.8 brakes) results in 8.9% larger diameter, 18.5% larger total area, but only 10% larger pad area

I read a bunch of the older big brake threads again and it does appear that the main issues with the older 11" kits are the weak design of the Corrado rotors and the inability to properly vent them to keep temps acceptable on track.

Ok, now I am rambling. 30 min to go and I am out of here!!!

emilio700

iTrader: (3)

How many hours do you get from the front pads on the car you win races in?

I don't know SCCa rules for EP/FP but I'll assume if the top guys in the country run OEM hardware it's because they have to. It would be illogical to assume they run a $15K engine that lasts 20 hours but won't pop for brake hardware that knocks 22 lbs of unsprung weight off the car and makes the pads last 3x as long.

Ski_Lover

No dick helocoptering here. i Agree completely on the desire to reduce unsprung weight. I was just observing that you don't always need to upgrade your brakes. Just pick the right pads (and for some, like carbotech, bed them in properly so you don't get issues like the OP have). Winning road course races on a dedicated race car vs Track day fun are apple to oranges. The point is you can do just fine with stock rotors and decent pads.

emilio700

iTrader: (3)

Agreed that good pads on stock hardware works superbly for most HPDE and W2W guys, just not everyone.

I don't necessarily agree that W2W and HPDE have different requirements though. The pad life, unsprung weight and consistency gained with bigger brakes benefits both. The more power you have, the greater the benefit.

The "doing it wrong" statement chafes a bit. That statement assumes
A) The guys putting aftermarket big brakes on their cars are all slow, non-winners.
B) That everyone that does not share your priorities is incorrect.

I get that driving a Miata fast generally requires spending the shortest time possible braking in each braking zone but that is at threshold. My lowly 170whp Miata on 205s generally runs 2-4s off T1 lap records. Our 130whp/2300# PTE Miatas are now running 4s under SM records. Brakes that modulate better than OEM and don't taper after one hour are a good thing.

Braineack

iTrader: (62)

I have Corrado rotors in the front and sport rotors in the rear with ULTs F/R.

I dont have a prop valve right now, but I want to downgrade back to normal 1.8L rotors...I think even with a prop valve there will still be too much front bias, those suckers lock up so quickly.

Efini~FC3S

iTrader: (4)

I also don't know the Prod. rules 100% but yea, I'm pretty sure they are required to use the stock hardware. I'd bet my pension they wouldn't be using stock hardware if they didn't have to.

I'd also bet that an EP Miata with 185whp is putting new pads on every weekend...

Speaking of awful brakes on race cars, we put brand new Cobalt XR1s on the front of my Civic Si SSB car every SESSION at the runoffs. New pads, every session...

Rallas

iTrader: (9)

Do the regular TSE, Wilwood or 949 kits come with metric or standard bolts? It looks like standard hardware would be cheaper, but I like the fact that I only need my metric tools at the track and have made a point to use only metric hardware for that reason. Will a 3/8" bolt fit too loose in the 10mm hole in the factory spindle? The 10mm factpry bolts fit snugly into the caliper lug holes with very little play.

curly

iTrader: (25)

It's standard hardware. The bracket has four threaded holes, there aren't any on the hub, the hub has through holes. Standard taps, in the U.S. at least, are around .3 the cost of a metric tap, it's a no brainer manufacture the brackets with them.

Don't pay too much attention to the maths for the 11->11.75" conversion, it's been proven by plenty of track junkies how different the feel is between the two. Hustler's documented much lower caliper temperatures as well.

How's this for maths:

standard brakes:
$60 pad x 15 track days = $900

wilwood brakes:
$500 kit + ($60 pad x 5 track days) = $800

With the right track stock calipers will go through pads in a day. 14 track days is 2-3 seasons I would say for the average track rat.

With said $500 kit letting pads lasting about 3 times as long, you've made up for the upgrade cost in 2-3 seasons.

Granted one must look at rotor costs, which are $20 more per pair than stock units. So that $100 difference makes up for that.