A good customer of mine (and member of VMF - pesla) over in France was complaining about the Porsche's in his vintage racing group out-braking him. He has been using the stock 65-66 Kelsey Hayes 4 piston brakes. He needs to stick to 15" wheels to be legal but wanted more brake.
I decided to have a go at building the uber giant Boss 302 Trans-Am system for him. They used a 11" something rotor from a Lincoln pressed onto a drum hub and a 67 Tbird caliper. I'm using the same caliper but went with a 2pc 12" x 1.25" rotor mounted to an aluminum hat. This weighs a few pounds less than the all iron version. I'm supplying him with some Porterfield R4 pads for the track.
I'm pretty geeked that it all turned out ok. I'm even more amazed it actually fits inside a 15x7 Torqe Thrust D without any modification or wheel spacers!
Waddaya think?
On the left is the base rotor in our 11.25" kit, right is the 12" mofo. The aluminum hat really helps save weight. The 12" rotor complete with hub and studs weighs 3lbs LESS then the smaller 11.25" rotor with integral hub/studs. Big rotor with big cooling vanes = longer and faster races/sessions before brake fade. Less weight = less rotational inertia equaling quicker stops.
Thanks to all the VMF'rs and vintage race guys that helped me out with this project. Lets hope pesla can now hang with those squished Volkswagens!
Nice! I'm interested in pricing too, as I'm looking to run a vintage-looking D1-pad caliper and lightweight rotor setup on my '70 drum spindles, all which need to fit inside 15" Minilites. That looks similar to Cobra Automotive's kit.
Calipers with cross over tubes, street pads, stainless steel hold down clips and grade 8 mounting hardware
2pc heavy duty, 36 directional vane 12" x 1.25" rotors with aluminum hats. Shipped fully assembled and safety wired
Hubs with standard length studs. Timken bearings and seals. Dust caps, keyed washers, nuts and cotter pins
Braided steel flex hoses with all fittings to mount to stock hardlines
Caliper mounting brackets with grade 8 hardware
Price - $1799 - thats everything in 2 boxes with no parts for you to source or modify to make it work.
All components are available separately for those creative guys that like to fiddle. 8-)
Porterfield R4 racing pads, duct plates, rotor stress releiving (heat treating), ARP studs, 15x7 TTD wheels also available.
Shaun, Cobra Automotive in CT has offered a similar conversion for quite a few years for vintage racing. Have you compared your offering to theirs in terms of specs and pricing? I'll make the comparison myself but I am interested in your thoughts.
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Shaun, Cobra Automotive in CT has offered a similar conversion for quite a few years for vintage racing. Have you compared your offering to theirs in terms of specs and pricing? I'll make the comparison myself but I am interested in your thoughts.
Rotor and caliper specs are the same.
Last time I checked theirs was $1850 with NO hubs, studs, bearings, seals, dust caps, bearing retaining washers and nuts and cotter pins. Piece all that together and you are over $2000.
How does this compare to the numerous "big brake" kits with 13'' rotors, etc.
Is a big rotored still functionally superior, aside from the need to run 17'' wheels?
P.S. that disc is awesomely thick. 100% Beefy. Looks like an amazing product for vintage racers.
Think of the rotor as a heat sink, the bigger chunk of iron the more heating it takes to soak it. But bigger isn't always better. A big heavy rotor may have great heat soak properties but its like a flywheel - spinning round and round and needing to be stopped. The heavier it is the more it'll take to stop it. Same is true for big heavy wheels and tires.
The brakes are also unsprung weight so using just the right size rotor to absorb the heat is the ideal, and not any larger. Most people however couldn't care less. Big rotors just look cool! Me included! If we were all racing for money then we'd run only what was required and nothing more.
The 12" 2 piece rotor with aluminum hat in this kit including its hub with studs installed weighs 3lbs less than a stock 1970 Mustang 1 piece rotor/hub... The huge 1.25" width will allow greater cooling than the stock .810 of a 1970.
So this rotor is the best of both worlds. Light with good cooling capabilities.
To answer your question, I think most people that go with 17" wheels want the wheels that size and not 13" brakes. They NEED the 13" brakes to fill the wheels and the increased diameter helps the leverage to slow down the increased weight. I wouldn't say that 13" rotors are superior to these. Most of the brake decisions are driven by peoples wheel choice. Your either an old school 15" wheel kind of guy or a 17" restomod guy.
Awesome stuff and fair price too. If I wasn't trying to piece together a new engine.....
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70 Mustang Vert--Konis, Addco, springs, Shelby drop, SSBC front discs, 2.75:1 T-lok, Magstars, Michelin X-Ones, 302, Autolite 4100, cam, Hipo manifolds, C-4. Not a car like I had when I was a kid--rather, a car like I WANTED to have when I was a kid.
Also into American Flyer electric trains--Its never too late to have a happy childhood.
I just finished installing my version. I'm using disc brake hubs and 68 Lincoln rotors (11.75 x 1.18), obviously heavier than what you're using. On the other hand, I got the (new Raybestos) rotors for only 25 bucks on Ebay . Mine are an almost exact copy of what was offered back in the day by Ford, as described in the Boss 302 Chassis Modification manual.
I've only made a short test drive last sunday and I suspect that I still have some air in the system, so I can't really comment yet on how well the work.
I'm also using Torq Thrust D wheels but had to grind off quite a bit of the outer ridge on the caliper and clearance is still minimal. Maybe your rotor is more offset than mine?
Did you make the caliper brackets yourself or did you buy them from Cobra Automotive? I got them from CA (not cheap, $375).
ABS brakes now offers aluminum versions of those calipers. They're exact copies and require therefore, like the iron originals, some machining to make them work for this application (drilling out the threaded mounting holes, spot facing the mounting surface, grinding off the ridge on the outside for caliper clearance).
I just finished installing my version. I'm using disc brake hubs and 68 Lincoln rotors (11.75 x 1.18), obviously heavier than what you're using. On the other hand, I got the (new Raybestos) rotors for only 25 bucks on Ebay . Mine are an almost exact copy of what was offered back in the day by Ford, as described in the Boss 302 Chassis Modification manual.
Did you make the caliper brackets yourself or did you buy them from Cobra Automotive? I got them from CA (not cheap, $375).
I've only made a short test drive last sunday and I suspect that I still have some air in the system, so I can't really comment yet on how well the work.
ABS brakes now offers aluminum versions of those calipers. They're exact copies and require therefore, like the iron originals, some machining to make them work for this application (drilling out the threaded mounting holes, spot facing the mounting surface, grinding off the ridge on the outside for caliper clearance).
I read alot about the 1 piece rotor version but liked the bling and weight savings of the 2 piece. They sure are alot more expensive though...
We are making our own billet steel brackets for this converison. Starts out with a 18lb lump and ends up at 2.6lbs. That is a lot of chips!
I think the CA ones are up to $450 a pair now! Crikey.
I've been trying to get ahold of a set of the aluminum calipers ABS is supplying but they have been on backorder everytime I call. I keep getting the, "they will be here in 30-60 days line...". The weight savings would be good (if the stifness remains) for the guys that don't need an iron caliper to be legal but want the vintage T/A look.
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Big brakes for little wheels
