Stock Single Piston Caliper vs Viper 4 Piston Caliper

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JGC403

JGC403

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I'm working on compiling parts to replace the little 9" drums on my Barracuda with a set of disc brakes with 11.75" rotors and pin type single piston calipers. The plan for the Barracuda is to have a nice street car and to also do some autocross. I was looking over Doctor Diff website and stumbled on the Viper Caliper mounting kit. Now both setups would be using the 11.75" rotor. Would there actually be a noticeable difference between the single piston calipers and the Viper 4 piston calipers with the same size rotor. The rotor can only dissipate so much heat before there is brake fade.
 
Ehrenburg did that exact swap on the Bold Beeper (single piston to Viper 4 piston). As I recall, he did it on one side only and test drove it, and said it didn't pull to either side. So, I would guess that for ultimate stopping power there isn't a lot of difference between the two. But that didn't stop him from doing the full swap. My guess is he did it because he didn't lose any breaking, and gained control and better wear with the fix calipers.
 
JGC403 said:
I'm working on compiling parts to replace the little 9" drums on my Barracuda with a set of disc brakes with 11.75" rotors and pin type single piston calipers. The plan for the Barracuda is to have a nice street car and to also do some autocross. I was looking over Doctor Diff website and stumbled on the Viper Caliper mounting kit. Now both setups would be using the 11.75" rotor. Would there actually be a noticeable difference between the single piston calipers and the Viper 4 piston calipers with the same size rotor. The rotor can only dissipate so much heat before there is brake fade.
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Check your clearances on the pin type caliper brake line fitting. It likely will not clear your lower control arm.
 
Jimacuda said:
Check your clearances on the pin type caliper brake line fitting. It likely will not clear your lower control arm.
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Have'nt heard that before in all of the disc brake swap stuff I have been reading. Were you using the correct caliper? Late B-bodies had the brake line fitting in a different spot compared to all of the other pin type calipers.
 
Viper calipers require 17 in minimum wheels to clear the calipers. Not sure if the conversion parts are available still.
 
JGC403 said:
Have'nt heard that before in all of the disc brake swap stuff I have been reading. Were you using the correct caliper? Late B-bodies had the brake line fitting in a different spot compared to all of the other pin type calipers.
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They were 74 B body pin calipers. None of the pics I've seen show a different location.
I had a set of slider brackets and new calipers so I just swapped them out.
 
Jimacuda said:
They were 74 B body pin calipers. None of the pics I've seen show a different location.
I had a set of slider brackets and new calipers so I just swapped them out.
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I think you had the wrong calipers. There were two different pin types used on B-bodies. See pic below, It sounds like you used the left one with an X under it, you needed the ones on the left 4 and 5. The correct B-body ones are 1972 Down or all E-body ones.
calipers.jpg
 
Yup....X marks the spot.
Good info to know, thanks.
Now, what to do with that set of calipers...:rolleyes:
 
66fs said:
Viper calipers require 17 in minimum wheels to clear the calipers. Not sure if the conversion parts are available still.
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Pretty sure that only applies when 13" rotors are used.

Per the info I saved for the old AR kit, the 11.75" kit with Viper calipers could use most 15" wheels. The DoctorDiff kit is different in that it uses a different kind of bracket (machined aluminum vs. flat plates with spacers) and a different rotor so pad spacers aren't needed, but I suspect the caliper location didn't change so I would guess a 15" wheel still works. But it isn't spelled out on the website, so if it where me (and it mattered), I would contact Cass to make sure.

BTW, when I say 15" wheels work, that doesn't mean every 15" wheel will work. The caliper can hit the spokes of the wheel even though the hoop doesn't, so the wheel should still be verified.
 
The largest Mopar caliper has a 2.75" piston diameter. Not many multi-piston calipers have this kind of combined sq.inch piston-surface (thinking Wilwood).
Although I don't know how much surface area the Viper calipers have.
 
JGC403 said:
... noticeable difference between the single piston calipers and the Viper 4 piston calipers with the same size rotor. The rotor can only dissipate so much heat before there is brake fade.
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Must be a difference since they jump thru hoops to make multi-piston calipers, w/ 6 pistons are now de-rigour in Corvette world, plus wide open wheels to show them off in bright colors. Fade comes from the pad material melting. While the rotor temperature is part of it, if the pad touches stronger at just one point it will heat up there more. With more even pressure all over the pad, all points stay closer to the same temperature and also conduct heat into the rotor better, where it gets dissipated into the air (kind of like a rotary fan).
 
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