A larger diameter master will give a firmer pedal that takes more effort to push, which is good if you have changed the piston sizes on the calipers enough that the pedal is getting squishy. Stock Miata masters are 7/8 or 15/16, there is a 1" master available that bolts on (requires custom brake lines) out of a mid-90s 929, or 949 Racing sells a kit to use a Wilwood 1" master. See the big post on miata.net for a lot more info on the various master/etc sizes over the years, but I would guess your 1.6 car probably has a 7/8" master.

IME, using Dynalites/Dynapros up front and the FM rear kit (Wilwood Powerlites) with a 15/16" master makes for a very unsatisfying pedal feel, and the 1" master is a really good idea with that.

--Ian

 

We always swap in a 1" Wilwood master cylinder. Much firmer pedal. It also allows us to use higher MOT pads which tend to have higher .mu. Too small a master on a high .mu pads can get difficult to modulate. Lots of brake torque is a good thing right up until you can't modulate it. OTOH, modulation is everything. I'll take a low torque pad that modulates and releases well over a high torque on/off switch any day.

 

Even on stock 1.8 calipers, a 15/16" master and matching booster were a nice upgrade in pedal firmness on my car. If it weren't for the fact that I got the master together with the booster, and the fact that I was hesitant to mess with getting the lines to fit on a non-Miata master, I would've gone 1". Together with the stronger MSM booster, pedal effort is nearly identical (if you do the math, it should be like 10% lower, which is not something I can feel), just with a fair bit less pedal travel.

 

I look forward to hearing more about the Stoptech kit as it evolves. Last I heard they added a 38/36mm caliper to better match the sport rears. Now if they can only add a 11.75 disk option we got a clear winner.

Cobalt makes pads for the ST40 so that makes this option even more appealing.

 

Double post

 

If the Wilwood 4 piston Dynopro calipers with 11 inch rotors fit inside a 15 inch wheel will the 6 piston Dynopro on 11 inch rotors fit?

 

Hi Emilio!
I noticed that you are going to be running a Tilton pedal set on one of your builds?

My son is 6-8" and I am looking at the 600 series underfoot assembly to create a little more leg room for him. Not sure but I believe the set may be gold plated or diamond encrusted?...Jeez!!!!!
We bought your your stage one brake deal (2000 NB) and though they seem more than capable to me, but given our 350hp + goals I am told more brake is in order....The horsepower is probably a year out while we build and sort the rest of the car (Xida coilovers and big grip kit is next).
ATM I feel no pressure to move toward a BB setup and I am happy to wait and watch what you work out here (happy to pay more for spectacular brakes!).

That said....I would like to sort out that peddle arrangement in the next 6 months or so.
From your comment above I assume I should be looking at double 1 inch cylinders along with Tilton's brake bias system?
If so how will that setup work until the big brakes are installed?

Thanks in advance!

Jamie

 

There is no space to be gained inside the car with any pedal assembly. The space we gained is under the hood by deleting the booster. I would recommend sticking with the OEM pedals. Don't overthink it.

6-8", you will need to cut a seat sized hole in the floor, fab a box 1-2" lower than the stock pan and mount your seat in it. Make sure that new pan is thick enough to not flex and also provide puncture protection if the car is struck underneath.

 

Damn, 6'8". I would recommend a different car....

Good luck.

 

He is 6-5" that was a miss type.
Still...with the Kirkey seat bolted to the floor he still misses the broomstick test by about 1/4 inch. I have been looking at a floor drop kit that Advanced Autosports makes.....It is 16 gauge, but even still adding a bit more protection underneath is a good idea.

Thanks for setting me straight on the pedals! Time to pull apart the dash and see if I can raise the steering wheel a bit....Maybe a bit smaller of a steering wheel as well.

Looking forward to seeing what you come up with on these brakes Emilio!



Miss typed there he is 6-5"
Still a tight space though!

 

There's also https://www.advanced-autosports.com/...ata-floor-drop which saves the fabbing of the box.

 

Reading comprehension.

 

Whoops, what I get for looking at email notifications more than the thread itself.

 

My comment of adding more reinforcement probably threw you off.

The Advance autosport kit does meet spec miata guidlines...If you have seen those guys drive (the new ones)...thoughts of 16 gauge of protection will make you scratch your head!
1/4 inch plate might be more appropriate!

Either way.....16 gauge between butt cheeks and disaster, does not meet with my approval ...So I will add more.

 

Well, arguably it's relatively infrequent that things penetrating the underside of the car is an issue, even with Spec Miata, but you never know...

 

I don't know. Around here they're called "wreck" Miata for a reason and I have seen some really bad wrecks :(

 

What about fitting ST42 calipers on stock 10 inch rotors? Possible or not?

 

If you make your own brackets, sure.

 

Thanks a lot Emilio on your reply. I searched a bit and it seems that for the 10" rotors a slight difference in measurement in the Stoptech kit brackets is needed. If my calculations are correct, 1/2 inch movement of the mounting holes will do the trick.
Do you have a schematic or a big close up picture of the brackets?

 

1. The ST42 in the miata BBK is made for a 0.81” (20.6mm) thick rotor. The stock rotors are 22mm thick. Small difference, but the tolerances are tight enough that stoptech doesn’t recommend using the 20.6 caliper on a 22mm rotor. They do make an STR-42 caliper specifically for a 22mm thick rotor, however.
2. Wheel clearance is really bad when you move the ST42 caliper far enough inward radially to work with a 10” rotor. You run into clearance issues with the mounting pad of the wheel, not with the spokes or the outer barrel. I’m sure there are some wheels that would clear, but 6ULs will not work without a spacer.

The good news is that the ND miata uses an 11” x 22mm rotor that’s a perfect fit for the NA/NB. I’m currently running the 22mm STR-42 caliper on my car with the 11” ND rotor and a custom bracket setup. I’ve been trying to decide whether I want to sell a few sets of brackets or just give the info back to mt.net for free. I don’t want to **** up Emilio’s thread any more so PM me for any further discussion.