you do realize you did a "that's what she said" to your own line... :P

Go dynapro. it has a bridge bolt so it should be stiffer. it's still a 3 piece caliper so it's not going to be stiff. as far as calipers go it's less worse.

Mine's pretty stiff. I can't imagine it getting much stiffer. The steel braided lines that come with the V8Roadsters kit probably help that as well.

And for anyone using stock calipers that is still using the anti-squeak shims from the auto parts store, ditch those spongy bastards. I couldn't believe it when I saw some on a part time track car the other day.

You previously alluded to another caliper that would match the bolt pattern and dimensions of a Dynalite, while being significantly stiffer. Is it available or still in the "maybe someday" category.

Alternatively, a radially-mounted Dynapro would be a stiffer solution, correct?

radially mounted vs lug mount shouldn't make a difference. some very cheap calipers it does, that's from a cheap materials/poor engineering stand point. if they are not engineered correctly the lugs will deflect, as a radial mount's mounting point us usually a billet piece of aluminum.

calipers that will bolt to a dynalight mounting point...Stop tech is coming out with a 2 piece/Bridge bolt caliper now. They will retail for 500ea. Baer has a caliper that is two piece, square O ring, beef little unit. the Baer retails for 250ish. it's also a huge body caliper, it's going to be heavy and i'm not sure if it will fit under a 6ul.

any more questions?

Is there any significance given to the type of motorsport when deciding on a system?

I.e , is there a difference when building for rally/off road racing, road racing, endurance, ect?

Or is it all the basics, with a much brake as you can get?

Absolutely.

The very first question I ask when building a kit is “Tarmac or Dirt?”. As I said before the Tire stops the car, not the brakes. The amount of traction that a tire is able to produce traction changes that amount of braking you need. Equip a rally car with a 408mm Brake system and the driver is going to be doing more modulation of the brakes then driving. Anyone that has driven a super moto knows what I’m talking about. As soon as you hit dirt your world changes, your riding style changes, your power delivery and braking changes. The clearest example of this is with a dirt bike. Notice the 22” rim ( yep a Rim it has spokes so it’s a Rim) but it only has one caliper and a 150mm x8mm Stainless steel rotor. Any more than that and the brakes will overpower the tire and you would lose all modulation.

For a miata - Rally racer the factory brakes can be enough, I would insist on using a low Torque race pad. This is to deal with the elevated temperatures of motorsport.

Dynalite Usable pad material thickness excluding backing plate ~8.4mm
Dynapro 4 piston Radial mount Usable pad material thickness excluding backing plate ~11.2mm

Dynapro 4 piston Radial mount Pads last at least 25% longer and yet cost the same based on the pad thickness that can be used up.
Dynapro 4 piston Radial mount calipers have better radial clearance to the wheel and slightly less spoke clearance due to the thicker pads.
Dynapro 4 piston Radial mount calipers are stiffer but I don't know how significant it is.

I do believe I was the first pioneer of 11.75" rotors and Dynapro 4 piston radial mount calipers fit into 15" miata wheels for a serious track car like 9 years ago I developed my kit. My wife kind of freeked out when she came out into the garage and I had the brakes off her brand new Mini Cooper seeing how the mounting compared to my miata.

from what i read the mounting point for a miata <-> mini are almost identical..

Yes that is what I figured out almost 9 years ago when I ordered a Mini Cooper 11.75" wilwood off the shelf kit and with minor modifications bolted it onto the front of my Miata. Also upgraded the rears to 11.44" two piece rotors with some very simple to home fabricate relocation brackets for the calipers. At that time it was significantly better and even cheaper than anything any Miata vendor had put together. It has worked well.

Why is it a bad idea to reuse old pads with new rotors?

when you install any pad it will "cut" a rotor, this will insure that the Pad <-> rotor contact is at 100%.

Used pads have a grove already cut in them. using old pads and new rotor will shorten the rotors life, and give you ugly groves.

If the pads history is unknown and they can be cooked. that's about all the reasons i can think of.

^^^basically, the pad and rotor surfaces have to mate and be bedded to each other. They're monogamous. :)

basically yea. i haven't seen anyone try to reuse old pads with new rotors. Generally the rotor is done same time as the 3rd or 4th set of pads. then re replace them both.

But, if using the stock Miata braking system where rotors are 10-20% the cost of good pads . . . .

Have you any experience of AP Racing, specifically their front kit? The rotor is smaller at 10.8" and they state the need for 16" aftermarket wheel, but who knows if they have tested the common 15" aftermarket wheels thats in use.

From my experience with tracking Volvo T5s (nobody snigger!) the quality of the calipers, rotors and kits in general from AP are extremely high, but you do pay a hefty premium.

Be gentle, you have the honour of my first MT post ;)

Miata fitment http://www.apracing.com/drawings/P16178.pdf
Just compare to the 6UL profile.

If not going with kits, their Floating 295x25.4 CP3580 combined with CP5040 caliper would maybe make something that could fit our favorite 15" wheels, with spacers to clear the spokes (thicker caliper and a thicker disk, the steering knuckle is close).
The bell in their kit is probably not useful so both the bells and radial adapters need to be custom.
Twice the cost of a Wilwood Dynapro mini kit with TCE Miata customization, if you can make the custom parts at low cost.

AP and Alcon are not Wilwood, but sometimes the cheap stuff is good enough (especially if it can fit more brakes under the favorite wheels).

9 times out of 10 the cheaper options ends up having a higher cost. You really should read threw this thread on why you need a quality system.

I know AP, and I Know The People at AP very well. Jeff was huge competition for me when i worked at PFC. Dare I say we had more cars with PFC rotors then J hooks :P. Now I work with jeff as OG sells AP as well. I was unaware that AP had a NA/NB kit. i'll look into it and see if it's what we need. It's quality will be top notch.

interesting I hadn’t looked too hard at AP before.

Looks like this caliper would bolt on the same bracket as a Dynapro Radial.
AP Racing - Race Car - Brake Calipers - Pro 5000+ Range - 4 Piston Caliper Families - CP5040-2/-3/-4/-5 - 152mm Centres

This caliper is more similar in terms of beef in what I think would translate to stiffness and pad area however.
AP Racing - Race Car - Brake Calipers - Pro 5000+ Range - 4 Piston Caliper Families - CP5040-10/-11/-12/-13 - 130mm Centres

The other issue is the rotor width AP has 25 and 28mm rotors where the common width that is used and fits well on a Miata is .81” 20.57mm. The off the shelf Mini Cooper Dynapro radial 11.75” kit places the rotor in pretty much optimal position. ~2.5mm clearance to the stock tie rod end and it yields a few mm of spoke clearance to quite a few common 15” Miata wheels. Adding 5-8mm of rotor width is going to create some more limitations on wheel fit.
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Nah, it's just full of "small stuff that have worked for 20 years is dangerous" bullying. ;)
Theories are fine, but these small cars makes it a huge bag of compromises. Some of us are cheap bastards as well.

All out performance for 24h on 18" slicks, sure, bring it on.
Restrict to 15" with 23" tires for less than one hour and the situation isn't identical (you can get away with a little less optimal stuff).

When we made the local Alcon/AP/etc rep test XP20/XP10 on his Nationally second Miata (140whp) he stopped thinking about upgrades.
I have got some advice against the Wilwood Dynapro 11.75" kit from him but he fully understands the difference between a "ÓTS" $1K kit that is a huge step up from working stock and a $2+k custom build that will "just" have even thicker pads (and untested fitment), if we disregard the longer service life on the calipers (and assumed stiffness and the cooler name).

The outer tie-rod is real close to the disc so it's not that easy to just shift things further inboard (so a thicker disc will be more outboard between the wheel bearings than stock, I assume).

Edit: ^Bob is on the case, if 9 years on Dynapro is starting to get boring :)