Daft question of the week.

phil-hex;6845 wrote: with 2 sets of calipers would it not create more heat with the improved braking and with more of the disc 'covered' with calipers less area for the disc to cool?

must admit it would look the dogs B's but i reckon if it was do-able it would already have been done

my first thought was that heat would be an issue, when i come home from work on a night (1am anyway) with a "spirited drive" home i go through the annoying puddle in our grove and usually see a massive cloud of steam from the passenger wheel and can see the pads on the drivers side are bleeding hot...

thats with non AP calipers on the front, so i have say 3/4 of the disk open to air cooling, having less than half the disk available would certainly reduce the cooling air that come to them... your best bet may be to get in touch with AP themselves or possibly a touring car/rally/caterham race team? im sure they'd have the expertise required to better advise than us lot lol


as for if it was doable it would have been done... i find fault with that argument phil old chap... remember we are talking to the nutter building a supercharged K-Series engine!!!! lol

Nutter?? Where?? Who?? :dunno:

Oh, I see. :rolleyes2:

I think the biggest issue will be that the master cylinder is set up to move the correct amount of fluid for 4 calipers in total. Adding another pair to the front will need a bigger volume of fluid movement, which will require a longer stroke or a larger diameter master cylinder bore. Without a bigger bore you will need more travel on the pedal to give the same excursion on the brake caliper pistons.
Also, the pressure on the individual caliper piston will be reduced, meaning less braking effort at the wheels.

Andycolm;7156 wrote: I think the biggest issue will be that the master cylinder is set up to move the correct amount of fluid for 4 calipers in total. Adding another pair to the front will need a bigger volume of fluid movement, which will require a longer stroke or a larger diameter master cylinder bore. Without a bigger bore you will need more travel on the pedal to give the same excursion on the brake caliper pistons.
Also, the pressure on the individual caliper piston will be reduced, meaning less braking effort at the wheels.

Yep, that's what I meant about displacement. Shouldn't be too difficult to fit a bigger master cylinder.

CJJ;7158 wrote: Yep, that's what I meant about displacement. Shouldn't be too difficult to fit a bigger master cylinder.

I say fit two So, in effect, it would be two systems, that way you could connect the new system to a big, huge, red button on the dash that reads 'ONLY USE IN EMERGENCY' (or better yet one of those 'BREAK GLASS IN EMERGENCY' fire alarms)...the button would have to strobe ominously either way, of course!

Plus having a second caliper mounting onto somewhere, I'm assuming onto the original caliper mounting point too?
I would be very twitchy about transferring more load onto that point, it will be designed for one caliper and fitting a second will double the forces going through it, maybe overloading the casting or the bolts.
Also the extra heat via increased friction into the disks building up faster than they can get rid of it. Then you need bigger disks to give a bigger surface to dissapate the heat more efficiently.

The Prometheus;7159 wrote: I say fit two So, in effect, it would be two systems, that way you could connect the new system to a big, huge, red button on the dash that reads 'ONLY USE IN EMERGENCY' (or better yet one of those 'BREAK GLASS IN EMERGENCY' fire alarms)...the button would have to strobe ominously either way, of course!

Strobe or "Throb"?

CJJ;7166 wrote: Strobe or "Throb"?

Depends what mood your in I suppose...



...anyway back to the caliper question

I seem to remember reading somewhere ( American magazine I think ) about someone attempting this. The problem is some sort of harmonic vibration sets in, caused by the calipers not being able to produce matched forces. When all the pots are in one caliper uneven forces are distributed within the caliper and don't vibrate. Thats why you can get from one to eight pots all set in one caliper. I think motor bikes get round this problem by using twin disc's.
Why not try Citroen style total power brakes ? First time I tried one of those I banged my nose on the steering wheel and I was only doing about 20.

Andycolm;7163 wrote: Plus having a second caliper mounting onto somewhere, I'm assuming onto the original caliper mounting point too?
I would be very twitchy about transferring more load onto that point, it will be designed for one caliper and fitting a second will double the forces going through it, maybe overloading the casting or the bolts.
Also the extra heat via increased friction into the disks building up faster than they can get rid of it. Then you need bigger disks to give a bigger surface to dissapate the heat more efficiently.

could always replace the bolts with titanium ones lol, to play devils advocate a second.... would the 6 pots from AP that are the other option here not be heavier and cause the same stresses?