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Does anyone where to get RX7FB twin-piston calipers?
Part numbers in the homologation form are 4352 33 610 right side, 4352 33 710 left side. It is a non-floating twin-piston caliper for use with a 25mm disc.
That means it is unlikely that FIA scrutineers would ever have seen any either. The only dimensions are as stated above, no piston size is mentioned. It therefore follows that If I could find something that looks similar to the picture, has 55mm pistons and fits under 13" wheels I could make it work.
That means it is unlikely that FIA scrutineers would ever have seen any either. The only dimensions are as stated above, no piston size is mentioned. It therefore follows that If I could find something that looks similar to the picture, has 55mm pistons and fits under 13" wheels I could make it work.
i've never been teched to the point where they measured brake caliper piston size
I am building the car to Form 5713 for Group 2. The Girling calipers are only homologated in Group B.
Nissan Primera front brake discs are 8mm non-vented, fit the GSL-SE halfshaft flanges perfectly, will work with the GSL-SE calipers, are 250mm OD (no diameter is mentioned in the Form) so rear brakes are sorted.
The front struts will be Gp4 Escort Bilstein tubes in Toyota AE86 uprights and AE86 P/S steering arms to get the large stub axles and shorter steering arms to increase steering ratio.
AE86 brake discs are 242mm but other parts bin discs are available which are bigger. Investigating Brembo rear calipers for the Subaru WRX which look like the Gp2 front calipers on the form.
Sent the rear halfshafts and Nissan discs to machine shop to be bored for Gp4 Escort wheel studs at 108mm PCD.
Any idea where sells new GSL-SE rear calipers?
Girling AR Calipers were homolgated for the RX7 in GpA but they look very similar to the picture of the Tokikos in the Gp2 Form and have 54mm pistons so I'm going to fit them to the front. They are not made by Girling any longer but are reproduced in UK for Historic racing without the Girling branding which is great for me.
According to carbotech, the most awesome pads, the rear brakes on 13b 4 lug cars c 84-92 use the same rear pads so you might check into second gen parts.
FC calipers are completely different too. The handbrake cable comes in from the side instead of from underneath, and the hangers are massively different.
I know for a fact (personal experience) that the Lucas calipers from a early 00s Volkswagen front-drive (New Beetle, Golf, Jetta) are trivial to adapt to the Mazda cable. You have to clock the caliper down abut 30 degrees so the cable can meet to it, but that is okay since the mounting ears are in a completely different spot anyway. As far as I know, this type of caliper has only been available for solid rotors. Contemporary Audi A8s used the same caliper but with vented rotors, but their handbrake cables came in from a different angle. (Front wheel drive A8s may be an option, if they had twist-beam rear suspensions, but I have never seen a front drive A8 so I don't know. They also had 3.7 V8s instead of 4.2l, and they might not necessarily have had the vented rear discs)
Awesome thread for braking info! I am looking into this for the future, would be awesome to finally find out a better BBK for our FB's eventually. Will keep some of this info in mind!
So I've sorted the rear brakes in accordance with the Gp2 homologation form.
The GSL-SE halfshaft flanges have been re-drilled for Gp4 Escort studs which insert from the front and are secured with a nut on the back. The wheel locates on the stud shoulder.
The Brake disc is from a Nissan Primera also re-drilled to 108mm.
The calipers are GSL-SE with spacers made up to mount them.
I would ask how you plan to use calipers for vented rotors on solid rotors, but then I see the Escort wheel studs and forget what I had been thinking.
Lots of parts bin mixing and matching going on to keep this within regs. and homologation form. I'm keeping note of everything for the next idiot who wants to build a Gp2 car
12-20-18, 11:28 AM
