Hi guys,

Anyone here who put a racing pedal box into an FC before? Looking for suggestions / idea's.

https://www.compbrake.com/product/ma...inder-std-kit/

Came across this kit, don't find it super clear, if it would fit, sizes etc. but looks like it replaces the booster.

Any info / suggestions?

 

my friend made something similar and it will replace the booster. for sizing we have this on file, https://www.rx7club.com/race-car-tec.../#post10445081

"6:1 pedal ratio
5/8" front
7/10" rear

tested, proven."

JGRewe

 

Any issues with firewall flex?

The ratio on the compbrake ones is 5:1, and my brakes will be different but that's another story.

It looks like the easiest way isn't it?

 

it isn't any different than stock.
it is pretty simple. i don't know about this one, but my friends thing mounted the masters kind of in the stock spot and instead of the booster it had the balance bar thing, and then it just used the stock pushrod and pedal

 

So, after I sold my new wheels I just placed a new order and included the new set for the fc again. So I'm back at this.

For some reason I thought it was a good idea to buy absolutely massive calipers, hence the required new wheels.
The more I thought about it the more potential issues I thought of. But now that I'm here, I want to see this work. So I now got a pair of rear calipers also and the pedalbox might become my escape to get balance right. Not to mention that brake feel should be insane on the track. I mean, I hope it comes close to what I've been able to experience before.

Latest issue: Finding parking brake calipers. Currently stuck on wilwood mc4. Looks like the best option so far.


Here's a pic on the calipers. Both Brembo, both second hand from a maserati.
The 6-pot has already been paint stripped and no, the black one is not small. It is the 6-pot being that large lol.

 

Nice kit. We are ordering one also for a customer car. I couldnt make one for the cost of this one. Even shipping was reasonable.

 

Progress is slow, but we are getting somewhere.

The dual master "pedal box kit" is in, it required a little modification. Believe its made for an FD so its not that unexpected.

The brakes them selves are the main challenge though, but we are getting there. The discs that I ordered won't work with the 6-pot calipers, the pads will stick out. Found different rings which will be 360x32 while having a smaller ID.
The rear is the big issue. The 2-piston caliper will not fit the FD 294 discs. Had a look at 4-piston AMG calipers but fitment is even worse. axial mount will give me to much headaches. I am currently looking into porsche 4-piston calipers that are radial mount. I am awaiting piston sizes at the moment.

Also, I've bought jaguar parking brake calipers to make it all complete.

If things work out well, and there is enough interest, I might turn it into a kit so you can replicate this BBK setup.

 

Why not jut buy a big brake kit? They make them for the FC. Save you some headaches.
That looks like a nice piece of kit if you don't need a booster.

 

Because i'm not going to run D2 or Ksport crap. Going brand new brembo / AP / Alcon will cost at least twice as much and will also be a custom setup.
Its also a learning experience a fun to figure it all out. The headache part is finding the right stuff the way i'm doing right now haha.

 

With all the aftermarket ot factory 4 or 6 pistions calipers avalable it should be easy to build a ki

 

I must admit, this took way to long

Eventually I decided to start learning solidworks and buy me a 3D printer. Few more tweaks but I am getting close to the final design.

 

Very nice!
Pardon my ignorance but when creating the bracket, how were you able to determine the proper "offset value" so to speak for the caliper bracket and the rotor hat?

 

Well, it being custom and me starting from scratch, I can basically do what ever I want within a few parameters.

So simply put, what I did, I pushed the rotor as far in towards the spindle as I felt comfortable. From there its just a matter of trowing the caliper on and taking measurements. And perhaps a bit trail and error

 

It looks a bit heavy... Final design will have lightening holes, yeah?

 

I have been thinking about that but my knowledge doesn't go that far and I haven't figured out the stress simulation yet.

According to SW the rear bracket is estimated at 905 grams, and the front 736 grams

 

Not as heavy as I would have thought… don’t tell me it’s aluminum?

 

It is going to be yes, why shouldn't it?

 

You haven’t done stress simulations and are using weaker metal than the stock uprights… I’d suggest using steel.

 

Go look up any big brake kit, all aluminium. Both brackets and center bell in case of 2-piece rotors.

Not to mention that there are so many factory suspension parts from aluminium to be found on many cars out of the factory. Cast aluminium, not even billet aluminium.
Oh wait, the rear upright where the factory calipers mount to, is aluminium...

Just saying "aluminium is weaker then steel" doesn't cut it.

I don't know everything but i'm not stupid either.

 

I only mean if you can’t test the design.

 

I understand, but it's kinda beefy right? haha

I've got girodisc rings and they apparently use 6061 T6 for their hats, I was expecting something a bit more exotic tbh but if they use it for their kits it must be fine for my hats as well. I'd love to do simulations on the brackets but I just don't know how that **** works. Maybe I'll find out one day

 

Sorry if it was listed somewhere earlier on in the thread and I just missed it, but what width rotors are you using in the rears for your mechanical brembo parking brake caliper? Planning on doing a similar exercise with some PFC calipers in the future and trying to determine the maximum width of the parking brake caliper will allow. I don't have a part number for it so I can't find much documentation.

 

These are 22mm thick, had to grind out the parking caliper a little to make them fit and I am unsure if they fit with brand new pads. But for the parking caliper I don't care bout that.

I am considering making more kits if there is enough interest in these but I first want to test them before I do.

Due to non-rx7 related problems this is slightly on pause right now. And the first machinist I am talking can't start before august.

 

So unfortunately there are massive delay's at the machine shop which means I still don't have any brackets and stuff.

Delays after delays

For anyone waiting, this is what it is going to look like

 

Parts picked up from the anodizer about a week ago. They have been anodized black but due to my choice of hard-anodizing the added color doesn't show very well making the parts grey instead of true black.

The rotors have been assembled but I have to find time to put everything on the car and properly document things