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-   -   Big Brake fun (https://www.miataturbo.net/suspension-brakes-drivetrain-49/big-brake-fun-90132/)

Blokatos 11-10-2017 04:06 PM


Originally Posted by jpreston (Post 1451043)
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 shit up Emilio’s thread any more so PM me for any further discussion.

Very interesting stuff. I was more less sure that ND brakes have some compatibility with NB due to bolt pattern being the same. What about the ND rotor hat height? How does it compare with the stock NB rotor hat?

I must note that stock NB rotors are not 22 mm thick, they are 20 mm. So this aspect is covered.
As for clearence, using the template Stoptech is providing through their website, I checked and it clears my wheels, 14X6 inch hollow spokes from a '97.

https://cimg0.ibsrv.net/gimg/www.mia...b453f1bf76.jpg

It is not roomy in there but there seems to be a clearance of 3-4 mm which is more than the 2 mm Stoptech advises in their tech support webpage.
That all for the thread. I think they are relevant with big brake fun and useful.
The rest I will pm you, thanks :)

oregonmon 11-12-2017 03:43 PM

Sub'd.

nick470 11-21-2017 12:15 PM

So what's the consensus on the different caliper options? It's seeming like ST42>Superlite>Dynapro>Dynalite? And for the rear, Stoptech > dynalite > non sport rear calipers w/ sport rotor adaptors > sport rear caliper?

I keep jumping back and forth between Trackspeed's website and V8Roadsters looking at the brake options, I'll probably just get Dynapros in the front and sport calipers in the rear unless the Stoptechs are good enough to warrant spending the extra money.

And does anyone make that sport rear rotor adapter? I think TSE used to sell it but I'm not seeing it anywhere.

Savington 11-21-2017 02:09 PM


Originally Posted by nick470 (Post 1452817)
So what's the consensus on the different caliper options? It's seeming like ST42>Superlite>Dynapro>Dynalite? And for the rear, Stoptech > dynalite > non sport rear calipers w/ sport rotor adaptors > sport rear caliper?

You can't state a hierarchy of the calipers like that. The Superlite and ST42 serve totally different purposes. IMO there is no better setup on the market for a fast road race or endurance car than our Superlite setup, but it would be a pretty poor choice for an autocross car, for instance. Same thing in the rear, the "best" caliper depends on the usage.

emilio700 11-21-2017 02:11 PM

The Superlite is a bigger caliper than the ST42. Almost twice the pad area. The Superlite compares more to the much bigger ST40.

OGK, our time attack build and Vegas, our S1 Supermiata will both get radial mount Superlites with 16mm pads. Trackspeed uses the lug mount version to allow the thicker 20mm pad.
Pad volume of the ST42 is the same as a Dynalite which is 2.1
Superlite 16mm radial is 3.8
Superlite lug mount 20mm is 4.9

The ST42 is a very rigid caliper but the pad volume is what kills it in my view. Not enough gains from the added stiffness over the Dynalite to justify the cost difference.
Our current 11.75 radial mount kit uses the Dynapro 7812 pad, 2.1 volume

Jumbosrule 11-21-2017 07:24 PM


Originally Posted by Savington (Post 1452843)
You can't state a hierarchy of the calipers like that. The Superlite and ST42 serve totally different purposes. IMO there is no better setup on the market for a fast road race or endurance car than our Superlite setup, but it would be a pretty poor choice for an autocross car, for instance. Same thing in the rear, the "best" caliper depends on the usage.


Originally Posted by emilio700 (Post 1452844)
The Superlite is a bigger caliper than the ST42. Almost twice the pad area. The Superlite compares more to the much bigger ST40.

The ST42 is a very rigid caliper but the pad volume is what kills it in my view. Not enough gains from the added stiffness over the Dynalite to justify the cost difference.
Our current 11.75 radial mount kit uses the Dynapro 7812 pad, 2.1 volume

As the word, "optimization" starts being used more and more frequently in reference to the Miata, the differences between systems are important and have their own uses. The only thing you would need larger pad volume for is endurance racing? Otherwise the additional weight and brake thermal mass is overkill when a smaller more efficient rotor can absorb and shed heat more efficiently.

The Integra Type R that set the record at buttonwillow duriung GTA was on optimized brakes; his rotors/caliper weights were lighter than anyone else in his class and could heat soak after 10 laps or so. But the car never does more than 4-5 laps, because Time Attack. It even sacrifices ducting and radiator airflow for aero/more downforce so the brake thermal capacity was never pushed to it's limit.

Sames goes for those wanting to choose between the biggest thing that will fit and the best thing for the application; they are often not the same thing. If the Dynalites and the ST42 kits never fade on road course racing, the pad volume is essentially irrelevant, unless we are strictly considering how often the pads would need to be replaced.

As far as stiffness is concerned - the calipers themselves have much more to do with system stiffness than say, Stainless Steel brake lines. A flexible caliper can, "lose" up to 100 lbs of braking force with line pressures equal to a caliper with 10% greater stiffness. The driver can compensate at the pedal of course, but there is more potential to stiffen up the system inside the caliper than in brake lines and master cylinder bracing combined. It's no small detail.

jpreston 11-21-2017 07:37 PM


Originally Posted by emilio700 (Post 1452844)
Pad volume of the ST42 is the same as a Dynalite which is 2.1
Superlite 16mm radial is 3.8
Superlite lug mount 20mm is 4.9

Nope. ST42 uses the 16mm thick wilwood 7816 shape with 3.0 cu.in. pad volume.

emilio700 11-21-2017 08:03 PM


Originally Posted by jpreston (Post 1452914)
Nope. ST42 uses the 16mm thick wilwood 7816 shape with 3.0 cu.in. pad volume.

My notes from ST differ. Perhaps there is more than one version?

jpreston 11-21-2017 08:13 PM

Not that I'm aware of, but Brad can clarify if so. The 7812 is the same shape as the 7816 so the ST42 can use the 7812, but the 7816 fits too. There are 8-10 Stoptech BBKs in Lexington/Louisville and we're all running the 7816 pads. In the last WRL race we did at Mid-ohio, we saw less than 2mm of wear after an 8 hour race in a PTE car with 225 RS4s. Raybestos ST42 pads.

machschnell 11-21-2017 09:01 PM


Originally Posted by nick470 (Post 1452817)
And does anyone make that sport rear rotor adapter? I think TSE used to sell it but I'm not seeing it anywhere.

I contacted Track Dog Racing this week and they will sell just the rear caliper relocation bracket vs the full set as listed here https://trackdogracing.com/tdr-bbk18.aspx

Some prices quoted to me:
Brackets - $119.00
Rotors Slotted and Zinc Plated - $168.00
Rear SS Brake Lines - $75.00

Not sure I found anyone else that sells the bracket. The ones on Goodwin Racing are "out of stock" but the price is the same.

I'm also looking at the Track Speed Engineering kit with Dynapros, prop valve and brake ducts for the front once the holiday bonus kicks - Trackspeed 11.75 Gen2 Big Brake Kit

TDR has a cyber monday sale so I'll probably do that for now. When asked they did say the rotors are SP Performance (slotted) but I saw Stoptech and DBA slotted rotors for 30-40 less on Goodwin's site, but TDR said they will try to price match. So should I stick with the slotted, zinc plated rotors from TDR or save a few and go with StopTech/DBA? Car is a 400hp LS1 and will see some track days in the spring

Thanks

nick470 11-22-2017 11:06 AM


Originally Posted by Savington (Post 1452843)
You can't state a hierarchy of the calipers like that. The Superlite and ST42 serve totally different purposes. IMO there is no better setup on the market for a fast road race or endurance car than our Superlite setup, but it would be a pretty poor choice for an autocross car, for instance. Same thing in the rear, the "best" caliper depends on the usage.

My question was overly simplistic, so let me rephrase it.

For a forced induction car that will see 30 minute track sessions, autox, and a little street use, where the owner prioritizes brake feel, consistency, and low operating costs over rotational mass (light is always good but I'm not enough of an autox junkie to prioritize it), what brake setup would you recommend?

I asked that last question with caliper stiffness on my mind, I've heard some complaints about flex in Wilwood calipers and it's been my understanding that many prefer Dynapros over Dynalites for this reason. But it's hard to look at $700 options without also looking into the more expensive options, namely the Superlites and ST42, and wondering what additional benefits those would offer. It sounds like the pad size of the Superlite give it a nod for operating costs over the ST42?

At what point would you ditch the stock rear calipers?

emilio700 11-22-2017 11:47 AM

Nick,
You don't mention how much power or what tires. Theses are key. A JR45 on 205 T1R's and pump gas can run stock brakes. A TSE EFR 6758 on 275 Hoosiers needs 11.75 on L/R directional rotors, $250 pads and 3" brake ducts.

k24madness 11-22-2017 12:03 PM


Originally Posted by nick470 (Post 1453002)
My question was overly simplistic, so let me rephrase it.

For a forced induction car that will see 30 minute track sessions, autox, and a little street use, where the owner prioritizes brake feel, consistency, and low operating costs over rotational mass (light is always good but I'm not enough of an autox junkie to prioritize it), what brake setup would you recommend?

I asked that last question with caliper stiffness on my mind, I've heard some complaints about flex in Wilwood calipers and it's been my understanding that many prefer Dynapros over Dynalites for this reason. But it's hard to look at $700 options without also looking into the more expensive options, namely the Superlites and ST42, and wondering what additional benefits those would offer. It sounds like the pad size of the Superlite give it a nod for operating costs over the ST42?

At what point would you ditch the stock rear calipers?

Leaving Dynalite off the table all together cause it's not really a good choice for FI.

11.75" Rotors: cheap ones, 949 or Wilwood Spec 37. Whatever your flavor it will translate across all kits.

Pads: Dynapro and ST42 support the same 16mm thickness pads. In Cobalt pads I found the cost the same for either of those two at $169. Same for 12mm dynalites to so 4mm free pad with either. With the 20mm Superlites it jumped up to $269. With Hawk DTC the Dynapro 12mm (only size shown) at $92 vs Superlite 20mm at $172. If you a strong preference for a particular pad then this will weigh heavy in your decision. Do your own research here and use that info to decide.

Calipers stiffness: The STR42>ST42>Superlites>Dynapro. No huge deltas here though. Dynapro is pretty good but try and skip it if you can and go with Superlite. You current wheel size will dictate that.


Originally Posted by nick470 (Post 1453002)
At what point would you ditch the stock rear calipers?

When inner to outer pad taper becomes an issue. Jumping to 10.90 rotors will help up to a point. Then sport calipers are the next logical step.

jpreston 11-22-2017 12:20 PM


Originally Posted by k24madness (Post 1453025)
Calipers stiffness: The STR40>ST40>Superlites>Dynapro.

Nitpicking here, but... ST-42 and STR-42 start out as the same forging. ST-42 only gets the minimum required machining on bores and mounting surfaces, STR-42 gets ALL surfaces machined. They're functionally identical but the STR-42 is 0.5lb lighter and $100 more per caliper.

k24madness 11-22-2017 01:57 PM


Originally Posted by jpreston (Post 1453032)
Nitpicking here, but... ST-42 and STR-42 start out as the same forging. ST-42 only gets the minimum required machining on bores and mounting surfaces, STR-42 gets ALL surfaces machined. They're functionally identical but the STR-42 is 0.5lb lighter and $100 more per caliper.

Anodizing arguably adds strength on the STR but I agree they are essentially the same.

Savington 11-22-2017 04:50 PM

I have no data to back this up but I would confidently posit that the Superlite with the standard bridge-bolt is stiffer than the Dynapro. It certainly feels that way in the pedal.

DeerHunter 11-22-2017 05:42 PM


Originally Posted by Savington (Post 1453096)
I have no data to back this up but I would confidently posit that the Superlite with the standard bridge-bolt is stiffer than the Dynapro. It certainly feels that way in the pedal.

I wonder how much of that is the bridge bolt vs. caliper design. As a data point, I added the optional Dynapro bridge bolt part-way through my weekend at M@MRLS and enjoyed a noticeably stiffer pedal.

Leafy 11-22-2017 08:57 PM


Originally Posted by emilio700 (Post 1452844)
The Superlite is a bigger caliper than the ST42. Almost twice the pad area. The Superlite compares more to the much bigger ST40.

OGK, our time attack build and Vegas, our S1 Supermiata will both get radial mount Superlites with 16mm pads. Trackspeed uses the lug mount version to allow the thicker 20mm pad.
Pad volume of the ST42 is the same as a Dynalite which is 2.1
Superlite 16mm radial is 3.8
Superlite lug mount 20mm is 4.9

The ST42 is a very rigid caliper but the pad volume is what kills it in my view. Not enough gains from the added stiffness over the Dynalite to justify the cost difference.
Our current 11.75 radial mount kit uses the Dynapro 7812 pad, 2.1 volume

I cant find a radial mount NA/NB brake kit on your website? The radial mount dynalite only comes in clear or nickel I know thats not it, but interestingly the radial dynalite does have a bridge bolt.

emilio700 11-24-2017 07:55 PM

Hmm, neither can I. Will sort that out Monday and reply. We should have the components in stock and have already shipped an ND 11.75 Radial kit.

nick470 11-27-2017 01:19 PM


Originally Posted by emilio700 (Post 1453014)
Nick,
You don't mention how much power or what tires. Theses are key. A JR45 on 205 T1R's and pump gas can run stock brakes. A TSE EFR 6758 on 275 Hoosiers needs 11.75 on L/R directional rotors, $250 pads and 3" brake ducts.

TSE 6258 on 245 Rivals and 3" brake ducts. It's very unlikely that I'll do anything north of 300whp on the track, at least for the next couple years.


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