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Another reason I want an e-brake on my track car is for towing. I tow with the Transmission in neutral and e-brake on, and I’ve had steps loosen on long trips where the e-brake kept the car from flopping around on loose straps. I wouldn’t want to give that feature up even if it was a track-only car.
Completely agree with Peter, the stock rear calipers suck *** from a pad selection and reliability standpoint.
Another reason I want an e-brake on my track car is for towing. I tow with the Transmission in neutral and e-brake on, and I’ve had steps loosen on long trips where the e-brake kept the car from flopping around on loose straps. I wouldn’t want to give that feature up even if it was a track-only car.
@Smokey The Talon
The straps loosened on me once early on when I first started towing. Turned out to be user error. You want to have 2 rounds of strap wrapped around the ratchet before you truly start applying pressure to get the straps tight. Hopefully that made sense...
Once I learned that, I have never had a strap get loose again.
When I load my Trailex, I crank the front wheel/stand up to put it at an angle so I don't need any additional ramping than the ramps it comes with in order not to scrape the front. Sometimes I'm doing it an a not completely flat area to boot. No way I'd trust just putting it in gear to jump out and hook up the front straps without being worried it would roll back off.
I once saw a small, solid disc with single mechanical handbrake installed on the differential input flange for a minimal parking brake system
there may have been a point in time when they really served as an e-brake, but by and large they really aren’t much more now than a parking brake that keeps the car from rolling on a slope/incline. Even then you’re still supposed to turn your front wheels so they will roll into the curb if it ever gives way.
I wouldn't say "for the brave". IPSCO have been making those e-brake calipers for decades for the Viper community with no issues. I was actually going to post that link.
The Brembo E-brake kit is somewhat of the gold standard. The kit is about $1,500 in parts alone, but requires modification of the brackets. I put this caliper on my NSX with custom PFC brakes and it is a quality piece. But you get what you pay for.
Sakebomb's AP setup is decent as far as a whole kit is concerned but shifting the brake bias forward 3.7% (front and rear kit) to 6.4% (just front kit) is less than ideal. Just installing the rear SB rotor/caliper bracket makes a stock FD have 65% front brake bias, which is probably ideal for most setups.
Unfortunately, the RX7 market isn't large enough for anyone to come up with a proper BBK solution. Using the stock rear caliper has its own limitations and most people are going for the improved looks rather than actual performance (which costs $). Most setups I've seen and driven (with varying BBKs and brake bias *****) leave so much braking ability on the table, but 99.9% of people aren't looking at paying for a well-engineered solution.
Stoptech is probably the best front-only BBK on the market bias wise, they did do a front and rear trophy setup for MotoIQ's V8 FD. I'm going to inquire with my friends at MotoIQ about that kit, otherwise I'm probably going to make a custom Brembo GTS or Pista setup front and rear for my FD, but I need to decide if I keep my 17" wheels and go with 13" rotors front and rear or go with 14" rotors and then have to use 18" wheels.
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.
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here it is, but apparently they’ve since progressed more to the e-e-brake style since I last looked quite a few years ago, which frankly makes more sense than the dinosaur era solutions being suggested:
but having been more NA motor oriented in the past, I tend to be weight sensitive. Because those mechanical spot calipers and their brackets add up in addition to the weight of typical oversized rear brakes people mistakenly revert to …
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here it is, but apparently they’ve since progressed more to the e-e-brake style since I last looked quite a few years ago, which frankly makes more sense than the dinosaur era solutions being suggested:
but having been more NA motor oriented in the past, I tend to be weight sensitive. Because those mechanical spot calipers and their brackets add up in addition to the weight of typical oversized rear brakes people mistakenly revert to …
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It depends. Cast calipers and 1pc rotors weigh a lot. In many cases going to a lightweight aluminum caliper and 2pc rotor nets the same weight or a loss even with the caliper brackets. My 14" NSX rotors, calipers, brackets and pads were a couple pounds lighter in total over the stock 11.1" rotors.
Those e-brake calipers look pretty good for about $450.
Edit -
I just found this link and really like the idea of using a 43mm rear caliper off of a 2005-2014 Mustang (vs the 34.9mm stock FD caliper) with the stock Mustang 300x19mm rear rotor. There are also inexpensive 330 & 350mm rear rotor options to dial in the bias for whatever front brake system that's used. This is a great option for a larger rear caliper with an integrated e-brake:
yeah, I’m well familiar with it. Those mechanical spot calipers installed will add 8 - 10 lbs of suspended weight. Consider how hard you have to dig at a certain point to lose 10 lbs, I’d rather eat a dog turd than add that back on. Which makes me more inclined to go on a personal diet as well. 😂
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I ordered the SBG front and rear AP racing "Monster" BBK, along with the revolution Brembo e-brake kit (from Greenline) last week and today I got a refund and and email saying the e-brake kit was discounted.
This puts me in a bit or a quandary, I don't track the car just wanted a BBK to fill the void that 18" HRE 101s leave behind. I'd still like to be able to utilize the e-brake vs just leaving car in gear. The brembo calipers can be sourced elsewhere (wouldn't even be opposed to using the Wilwood caliper) but wanted to see if anyone out in FD-land has a template for the bracket.
My '65 Land-Rover has a drum parking brake fitted on the back of the transfer case (that's how they are). There is a disc-based replacement one you can buy that bolts on in the same spot. (Random photos off the internet below; not mine.)
The downside to using something like the disc kit is it going to add some weight with the solid steel rotor, but those do use the stock Land-Rover cable to activate it. So something like that may be possible.
Another (sorta) downside is that this is intended only as a parking brake and not an emergency brake. Even the drum one wasn't really meant for emergencies, but seems like it would be better than the tiny caliper and disc kit if you had an emergency.
Installing a parking brake caliper on the "regular" rotor at the hub of our cars is going to add to the unsprung weight as @TeamRX8 pointed out. The Wildood mechanical caliper weighs 3.3lbs with pads, whereas the electric ones weigh 5 lbs. (Editing the original post: it appears the weight is with a mounting bracket, from the photos and diagrams. will likely need to remove that one and fab a new one to mount to our cars, but at least there is already some weigh accounted for...) So to squeeze every ounce out of it the mechanical ones would be the way to go.
The type that mount to the back of the transmission or front of the diff will be sprung weight.
Another thought, but i hesitate to bring this option up since it is inserting a point of failure in your braking system... A line lock. It would only function as a parking brake, not a real emergency brake since it likely will lock the brakes up completely so only to be used when stopped (if even then - like i said i am not really liking this AT ALL.)
The Wilwood and the Brembo options above are parking brake only, not emergency brakes.
I guess the definitions would be useful here (mine, anyway):
Emergency brakes: in the old days the cable went to your regular rear brake drums / rotors and gave you all the stopping power you would normally get from the rears. Many cars used to have single circuit brakes, so any issue with the hydraulics could result in zero brakes at all. If that happened, you could actuate the rears with by cable. This was also the parking brake.
Parking brakes: were only meant to hold the car while parked. The Land-Rover system above is an example. The Tesla ones mentioned above are an example of factory ones; my guess is EVs have "regular" regenerative brakes that they weren't able to add a parking brake function to. Hence the Tesla tiny parking brake, that isn't going to do much in the event of a high-speed emergency.
So most of the options above are going to be for parking only.
I saw some newer calipers from Brembo and others that are hydraulic plus have a cable-actuated function for emergency and parking.
The lightest unsprung weight option might be a single-piston hydraulic caliper, using an additional MC on the parking brake lever. That would save the weight of the mechanism on the mechanical type, and the electronic motor on that type.
The challenges there would be finding a single piston caliper that works with the wider rotors our cars use with BBKs. A quick search didn't immediately turn anything up but Wilwood didn't offer any. More digging might find something.
You would need to run hard pipe back to the rears, affix to the body, and then add flex hoses. Not all that much fab actually.
Would also be interested in an alternative solution. Seems like a great deal of the heavily prepared (road race) third gens ditch the OE rear and just run a 4 pot with no parking brake. I was planning on using a parking brake caliper off of an 2003-2008 Jaguar XJR (made by Brembo) with some PFC zr22 rear calipers off of an asphalt late model. I put that idea on hold because it costs money to implement that could probably be spent somewhere else and I am not yet at the point in my track driving journey to necessitate such a development though I am not looking forward to frequent rebuilds of OE rear calipers and am of the opinion that the vehicle could benefit from more rear brake. I figure you could mock it up with some cardboard or wood or something that is easy to work with and then apply the requisite specifications to a more suitable material with the help of a machinist or fabricator.
That's what I have, Simon. Brembo 4-piston rears, no parking/emergency brake. Hence why i'm pretty interested in this topic. The mounting bracket should be relatively easy using the mock-up technique you mentioned. I made an alternator bracket from 1/4" steel plate for my Land-Rover mostly using an angle grinder. If you don't look close, it looks stock. Made one from cardboard, then from aluminum sheet, then the steel. Would look for a CNC place for these though.
I haven't tackled the parking brake before this since as Dale mentioned something that would function as an emergency brake would be higher on the priority, but since it looks like parking brake is about the best i will likely get, it dropped a bit lower. I just chock a wheel for now.
A follow-up on @TeamRX8 's post above on the Wilwood conversion: looks like that is a separate company doing the conversion, and they aren't doing them anymore?
But one person on that forum whipped up their own - might be able to do something similar. They disclaimed this as not for huge hills or emergency use, but as a first draft of something they were going to experiment with:
That's what I have, Simon. Brembo 4-piston rears, no parking/emergency brake. Hence why i'm pretty interested in this topic. The mounting bracket should be relatively easy using the mock-up technique you mentioned. I made an alternator bracket from 1/4" steel plate for my Land-Rover mostly using an angle grinder. If you don't look close, it looks stock. Made one from cardboard, then from aluminum sheet, then the steel. Would look for a CNC place for these though.
I haven't tackled the parking brake before this since as Dale mentioned something that would function as an emergency brake would be higher on the priority, but since it looks like parking brake is about the best i will likely get, it dropped a bit lower. I just chock a wheel for now.
(Insert the "Best I Can Do..." meme here).
Hey Steve. It appears that the parking brake and hydraulic caliper would share the same mounting points. I'm not sure to what effect it would be required, but it looks like you could either place the mechanical (parking brake) caliper in between the mounting holes on the rear hub and the bracket for the hydraulic caliper. It looks like either part of the latter mentioned caliper bracket would need to be planed down to adjust for the new material being added. Additionally you could have new rotor hats made with a lower offset to account for the added material.
There is formulae that would allow us to estimate the forces generated on the caliper bracket so one could be engineered w/ safe tolerances. You could probably get away with having the bracket for the mechanical caliper significantly thinner as it is only being used to hold the car and not stop it.
Additionally, it seems that there are other options for the parking brake caliper. I took a look at my father's '17 Quattroporte that has a standalone parking brake caliper and noticed that it was electronically actuated. Seems like something that could easily be wired up if one didn't want to run a cable. (We can bend wires in ways we cannot bend cables and lower maintenance)
Also, that rear brake setup of yours looks very nice. Was that something you had made from the days of the mailing list?
12-26-22, 08:40 PM
but you'd need a monster rear rotor for a 31.75mm nominal
since I last looked quite a few years ago, which frankly makes more sense than the dinosaur era solutions being suggested:
