Caliper Selection

[WALDOPIPE]

Hello Guys: i would like to know how wich teams use apracing calipers?. we were planning to use the CP4226 caliper but we have a doubt and its that in their web page says that the maximun pressure should be 1000psi but You might find for your application that as the caliper bore is so small you will need to exceed the maximum safe caliper pressure to stop your vehicle.

what its the expereice by using this caliper? what pressure value its enough in orde to block all wheels in the brake test?
Does any team knows what price are this calipers?

Thanks for all your help
Oswaldo Leon
FsaeUCV Team Captain

[WALDOPIPE]

Hello Guys: i would like to know how wich teams use apracing calipers?. we were planning to use the CP4226 caliper but we have a doubt and its that in their web page says that the maximun pressure should be 1000psi but You might find for your application that as the caliper bore is so small you will need to exceed the maximum safe caliper pressure to stop your vehicle.

what its the expereice by using this caliper? what pressure value its enough in orde to block all wheels in the brake test?
Does any team knows what price are this calipers?

Thanks for all your help
Oswaldo Leon
FsaeUCV Team Captain

[Composites Guy]

I think this is the same caliper we ran for our front wheels in '06. I did some calcs a few months ago that suggested that the bore was just too small to be running inside our 10" wheels (i.e. the pressure needed to lock up the wheel exceeded 1000 psi.)

They sure are cute and light though. The cost is huge! If I remember right they were around $300... better call to confirm that though.

[Buckingham]

I'm pretty sure AP designs most of their products with a good safety factor.

Most hydraulic systems have a 'rated pressure', a 'proof pressure', and a 'burst pressure'. Usually proof is at least 1.5x, and burst is at least 2x.

A good engineer would never install a product in an environment higher than its rating. A good racer....well, he might have a different opinion... http://fsae.com/groupee_common/emoticons/icon_biggrin.gif

[WALDOPIPE]

hello composites guy thanks for the reply, when you used the apracin calipers in 06 did you get any toubles? we are planning to use it in a 13" wheels with 8" brake disc rotors, what dou you thinbk about it? did your team had troubles in the brake test?

[Vinnie]

I have some experience with the AP-racing calipers; we have them at Delft from 2003. from 2003 we emailed AP what the maximum pressure is for these calipers. in 2003 it was 2000psi, in 2004 it dropped to 1500psi and now it is 1000psi. don't know if they had complaints or that they are just carefull on this figure.

in Delft we ran pressures slightly above 1000psi. now at (I made a team switchhttp://fsae.com/groupee_common/emoticons/icon_smile.gif) brookes we are currently investigating if we go for this caliper again as last years car had some trouble in braking.

one thing must be mentioned about these calipers; they are hard to bleed. in Delft we had troubles bleeding the car for 3 years. but last year the brakes were bleeded perfectly. the trick is that the brake fluid line in the caliper is on the opposite site as the bleed nipple; when holding the caliper with the bleed nipple pointing upwards air can be trapped behind the piston on the caliper side whitout bleed nipple!!! solution: during bleeding turn the caliper upside down and left-right in all possible position to get air from the side whitout bleed nipple to the otherside so the air can escape via the bleed nipple.

the last thing about these calipers is that they will visible flex when the maximum adviced brake pressure of 1000psi is applied.

but I have to say; we had these calipers last year on both front and rear and we had no problems at all, the flex in the caliper is very small and unnoticeable to the drivers. and we had the most firm pedal feel ever!!!

so its up to you.... are you a good engineer or a race engineer:P

cheers vincent
Delft '05 '06 '07
Brookes '08