I would like to put a rear BBK on my FD and retain emergency brake functionality. But, I haven't see a solution other then from Wilwood; I will not be using a Wilwood rear brake kit however. Is there a universal rear e brake caliper kit that could be mounted to the FD? Or is there a custom kit someone knows of specifically tailored for the FD?

 

A few of the JDM tuners have kits. Nengun, RHDJapan, etc would be good places to look

 

Also I would only consider doing this on a track-only car. When you get THAT deep into messing with the stock braking system some serious safety flags need to be thrown up. The e-brake is there for cases where you have a brake system failure and need to stop to prevent something REALLY bad happening.

Dale

 

This is the age old dilemma. The choices have been, use a stock-based rear system... can our OE rear calipers are hideous, have tiny pads that are a pain to change, don't except wider rotors, and aren't very durable to track heat (I roll with a spare set now)... or go with an off-brand aftermarket setup that's built a provision into their calipers/kits. Your comfort level may be different, but I just don't want to use any of those on my track car.

I would argue the big names like Brembo, StopTech, etc. are missing a trick here, because while they are selling "race" calipers from which most BBKs are based, the street/track market is huge, and for someone like me who's car is a pretty serious track car, I still drive it on the street occasionally and park it places that aren't perfectly flat (like my trailer even), and I simply cannot do with no e-brake. then there is the matter of some sort of failure for which these serve as the last resort.

A lot of newer cars use fixed calipers with a drum brake in the hub, and the aftermarket BBKs account for that. For our situation, ONLY a fixed race caliper with a second MECHANICAL spot caliper with enough strength (including the bracket) to slow and hold the car will really do. And that is a lot of engineering and cost. e-Brake calipers can be nearly as expensive as regular ones.

Revolution makes a Brembo ebrake caliper-based kit to go along with their rear Brembo fixed 4-piston caliper upgrade rear, but it's STUPID expensive. Like $2500 just for the ebrake portion which is calipers (with cable adapter) and a bracket:

https://www.rhdjapan.com/revolution-...tors-fd3s.html

I've been noodling a solution for a while, but since I don't know CAD I struggle to realize it. A solution is definitely needed.

 

a track only car does not need to retain the ebrake... a street/track car does.
@ptrhahn figure out what calipers you want to use and we can make it happen. I know the brembo e-brake calipers revolution is using are very expensive hence the very high price. other than that it is actually very simple to make

we have discussed this in the past in private but here is the information "in public" lol. The RS rears have served me well for any track day i have been.
I do feel that the overall cost to make this conversion is very high for something that i will personally not benefit anything other than perhaps the looks.

 

Unless you have a serious track car, that is also driven on the street, the stock calipers are adequate. Unless maybe with a front BBK there's too much front brake bias (i'm still on stock fronts). If that's the case, maybe a bias adjuster or sakebomb's rear kit will suffice

https://www.sakebombgarage.com/sakeb...tem-fd3s-rx-7/

 

I should probably rephrase and say that I'm not opposed to using the Wilwood Ebrake solution. I am just not using their BBK. If we were to get this from Wilwood, it should work with ANY after market BBK correct? https://www.summitracing.com/parts/wil-120-9809-1rd

The things that we would need is
1) Measure the Rotor Dimensions (How wide and thick)
2) Make custom mounting brackets.

The caliper should then connect to the OEM cable hardware?

 

I wouldn't characterize that as a "solution" so much as a caliper. Sure, they'll work, theoretically, but note the maximum rotor thickness is only 0.810 in. (20mm), so you're only going to be able use them with small-ish upgrades, but they would work with any other caliper since you'd need to fabricate the mounting bracket and figure out how to make it compatible with the stock ebrake cable anyway.

This style is probably closer, and can be had for rotors up to 1.1" thick:

https://www.wilwood.com/Calipers/Cal...o=120-15484-RD

 

Sure, it would be nice if some company offered this. Definitely needed if you are going to be running anything other then Wilwood. AP Racing, Endless, Project Mu, and the other BBK companies don't really offer an out of box solution; seems you have to fabricate your own.

Is R-R-Rx7 up to the task?

 

you should go somewhere with a disposable set of tires and try using it that way, because only then will you likely come to fully realize how it won’t save from anything much more than the vehicle rolling away when parked on a slope. Something bad is going to happen regardless if it comes to using it that way.


they’re out there though if you want to invest some time and effort into making it work,

Wilwood sells a conversion kit for one 4-piston caliper line


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but it only fits the 1” diameter piston caliper which is about a Miata application size

that highlights an important consideration though; if this is for a lightened vehicle or one not likely to see excessive triple digit speeds or endurance racing then you don’t likely need larger brakes and can even possibly downsize them for more weight savings like I did on my autocross-specific RX8

otherwise it seems to be an overseas only deal, not sure if there are legal/patent issues here in the US. It may require finding somebody they can ship to who can then forward it on here. There was one company in particular, but I’m not finding them and can’t remember the name, but I have the info saved somewhere and will dig it up.

A company called D2 came out with their version, but they’re very vehicle fitment kit oriented and you have to see if they can offer it on the FD3


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another one I stumbled across, but I didn’t study or look at it in detail

https://www.x-kema.com/parking-brake-calipers.html

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If you're handy at fab, or had a tame laser cutter, you could do it cheaper. The calipers themselves are around $Au500 ea new. https://www.scuderiacarparts.com/par.../156/805/24946 They don't very frequently come up secondhand here, but probably more prevalent over there, saw some a while back locally for $200 pair to give an indication.

The aluminium upright in the rear limits what you can do, so that horrible big lever arm mount appears inevitable. Depending on the BBK, you might get away with a RS/RZ length cable, but almost certainly the ends would have to change at a minimum....if not totally custom.

 

Check out my build thread. I use APG Brakes. They have a patented hydraulic rear ebrake that allows you to keep your ebrake functionality.

 

What are the piston sizes in there Pete?

I am looking for a rear caliper to balance out 2x 27.0mm / 2x 31.8mm / 2x 38.1mm in the front caliper

I am pretty sure Mr. Hahn and I have the right rear caliper in mind, but just in case there's another good option

 

The Sakebomb rear kit is such a good solution. OEM functionality, 2 piece rotor, and a step up from the already larger RZ rears

 

The problem with OE rear based systems are this. First, the pads are tiny. So the difference in area with a big aftermarket 4 or worse 6 piston front kit compared to stock is going to be huge and affect bias even more than most BBKs already do with piston sizes.

Second is, the caliper don't hold up well to track use. I literally roll with a spare set because I've had the piston seals leak or literally let go overnight only to return in the AM with a puddle of brake fluid in the wheel.

3. They are a pain to change pads on compared to fixed calipers and the pad selection is dwindling.

4. They're ugly.

 

interesting, page down for the handbrake info in the link posted below; the driver pumps up the rear brake pressure using the hydraulic foot-pedal system and then when the handbrake is engaged there are electric valves that block the pressure in the caliper

https://apgperformance.com/?page_id=228

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Thats how line locks work. Most people will use them on the front calipers so you can do gnarly burnouts. Throwback to my muscle car days

 

I'm not just making stuff up, I'm talking from experience.

I put the JP Motorsports brake booster line thing in that removes the brake booster hardline from the firewall. The clamp on the hose wasn't properly installed (totally my fault) and the brake booster didn't have any assist. This fortunately happened just as I pulled into my driveway.

Snatched up the E-brake and stopped the car instead of running the car into the back of my garage.

Again, 100% my fault, but there's a good reason all cars have emergency brakes. It's not just for parking. Yeah you aren't gonna have a great time slowing down from triple digit speeds, but in a street driving situation this can make the difference between easing off the road or getting in a wreck.

If the car is a track-ONLY car this is a different situation. I'm talking about a street driven car that sometimes goes to the track. Or a 100% street car.

I'm putting this out there because there's a lot of the line of thought "BECAUSE RACE CAR" that people get wrapped into. There's a really damn good reason Mazda put a lot of the systems and engineering into the FD, I want people to think about anything that changes things about the car that could result in an accident.

Dale

 

^^^^
This is why I'd ideally like a mechanical e-brake, on a mount strong enough to resist significant forces. Sometimes you just need a real e-brake in the real world.

Electric ones worry me, frankly, there's just something about a good old mechanical setup. I got caught in a local flash flooding situation a few years ago in which the road became blocked by a bunch of modern German luxury cars, because they all had electronic e-brakes that shorted and froze as they tried to creep through the shin-deep water, and they were virtually unmovable. Not that I drive the FD in those conditions on purpose, but still.

 

For an aftermarket type setup it would be cool to do the Toyota style e-brake. They have the regular rotor on the back with a drum brake setup inside the rotor hat as the e-brake. It's interesting since it's a totally redundant.

Wonder if a Supra type setup could maybe be used.

Dale

 

Yup, if you could figure out how to do it without adding width—the rotors/hats in the rear are very shallow, whereas the drum ebrakes I've seen the hat is sort of a deep bucket shape to account for the brake shoes, and that might not fit within our confines.

 

These guys make a mechanical caliper kit for Vipers. No idea on install difficulty or value for an RX-7.

https://www.viperpartsusa.com/produc...r-e-brake-kit/

 

Seems like the drifty bois would have a solution for this on the FD via some sort of dual caliper setup similar to that Viper setup.

 

a drum handbrake requires a steel drum to have any real emergency capability

what’s next; a solid steel disc to go with it? 🤔


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Good find but you'd need a monster rear rotor for a 31.75mm nominal
*edit* can work on a stock size rotor UP TO 31.75mm


For the brave, the VPU looks like a marked up version of this IPSCO

https://ipsco.org/newsite/product/ip...ing-brake-kit/