Stocker Commodore (V8) brakes vs AP 350mm kit

[35R]

Hi Guys

I want to run in the "lightly modified" Supersprint class next year, and one of the regulations relates to brakes.

The rule states that pads and rotors are free (to substitute whatever you want) provided the pad surface area doesnt exceed the factory spec pads.

So quick question, would you assume say the 350mm AP Racing 4-pot kit pad surface area would be greater than standard pads?

I've just had a quick look at the pads from each kit, and the be frank it looks like the AP Racing pads are actually SMALLER in surface area than the standard commodore pads??!! Now i assume the 4-pot caliper offsets this somewhat, but it had got me wondering.

Anyway now i have to figure out how to measure the surface area of a (curved) brake pad. Anyone got some tips on how?

[35R]

Here are the two pads in question (both fronts) the top is the stocker and the bottom is the AP

http://www.forrestfamily.com.au/duncan/track/misc/ap_vs_stock_small.jpg

[Dan_]

Go around the perimeter of the pad with a bit of string and cut it to length. Then take the string off and make it a rectangle or square. Then its just length multiplied by height!!

[35R]

Cool idea. Are you sure it will be right though? wouldnt it depend on the curves of each item? I suppose it would be reasonably ok for like shaped objects

[MrKeen]

could you put on 6 pot ap,s they were an optional upgrade ? Still a holden brake set up

[35R]

Josh i think as long as i follow the rules (that being the pad size constraint) i think i might be able to put anything on really.

I'm not unhappy witht he AP kit - it's a great kit for what it is. I have it on the car now and would like to keep it installed for next year. I think given the pad size is basically the same (AP 4-pot vs stocker) i may be able to leave the kit on.

[Dan_]

Cool idea. Are you sure it will be right though? wouldnt it depend on the curves of each item? I suppose it would be reasonably ok for like shaped objects

Yeah it will be right. It would be the same as mousing the pad into a rectangle

[35R]

ok. i am still confused though. See the attached pic, the shape with a chunk out of it - would measure bigger (surface area) using that method no?

[Dan_]

ok. i am still confused though. See the attached pic, the shape with a chunk out of it - would measure bigger (surface area) using that method no?

I dont get what you mean mate? Sorry

[35R]

I dont get what you mean mate? Sorry

Not sure if you can see the attached pic.

If you can, imagine using the string method to derive surface area - i dont think it will work.

[Dan_]

hmmm now i think about it it may not work. SORRY lol

[35R]

Not sure Dan, bit of a head bender!

i've tried another idea... i've "cut out" each pad from the pic (using paint shop pro on the PC) and pasted each into identically sized (transparent background) images. So the only "data" in each pic happens to be the cut out of each pad. I've then saved each pic; the file with the stocker pad reads 810kb, and the AP reads 780kb. Pretty crude i suppose, but it shows the stocker pad is about 5% bigger.

[235rwkw]

But the rules don't allow the AP 4 piston caliper unless factory fitted according to those rules. So its back to 2 pot. unless you get a hsv.

[GTS Listy]

Go to any decent brake shop or a mobile brake machine company. They will have a book with all the replacement pads for each type of brake caliper. Ie bendiz, ap s, harrop ect. The brake pad companies have diagramms of each type of pad so when you pull out a brake pad they can compare the alternative brand for sizing, dimentions, surface area etc.

[Duffman]

There's an easy way to get an accurate measurement of the surface area if you have a bit of time. It's one of the methods used to measure curved areas on construction plans.

Draw evenly spaced vertical lines on the pad surface(say 10mm apart) and measure the height of each line, then multiply it by the spacing then add all these small areas together. Basically your just dividing it up into small sections, measuring each section individually and then adding them all together. I may have explained it poorly but when done right it's surprisingly accurate.

Or you could just ring someone up as Listy said :D

[35R]

But the rules don't allow the AP 4 piston caliper unless factory fitted according to those rules. So its back to 2 pot. unless you get a hsv.

I suspect you are right, whilst the rules state you can use any rotors and pads, it doesn’t imply freedom of calipers. However I have asked the people that look after the regs to confirm.

Another option is to run this kit:

http://www.nvu.com.au/products_single.php?action=showproduct&cat=4&id=427&page=1&section=1

Which I am told was an option on Holden cars (albeit badged "Monaro" and not "HSV")

[2 cylinders shy]

I believe that that kit (330mm C5 Caliper) was not available on a holden.
The one you are thinking about is the 328mm Monaro/SSZ with the C6 caliper Kit with the newer/better calipers. The are simmilar though.

05A-042002 Sleeve Reducing x 4
72A-042001 Bolt Caliper Anchor Front x 4

Calipers

92185392 RHF SSZ TYPE
92185393 LHF SSZ TYPE

92162969 RHF MONARO TYPE
92162973 LHF MONARO TYPE

Discs

92161569 DISC ROTOR

Pad Set

92175204 PAD SET FRONT


Maybe they will let you run in "T3" spec like Brocks Monaro :helmet:

Good luck with next year.

[235rwkw]

not sure they will say yes.

they are just saying use whatever brand of rotor or pad you like, as long as its factory specs on the pad.

Spose if you want to stretch the rules, you could make new brackets to fit the 2 pots calipers with your current rotors, maybe. With Red yellow pads to suit the 2 pots, may perform better than current like that with a little more pad material than you have now. but i'd ask them first, you don't want to turn up and be disallowed due to mods.

they need to be more specific on the rules, very open to interpretation as is.

be right if you had a GTO...

[35R]

Thanks guys.

Regs dont mention calipers, which is constraining (given it's not listed as a free item) but fair to assume stockers only in the 2D class.

If the kit was offered as an option from the manufacturer, i can use it. So whilst HSV stuff is out, the PBR kit as offered by holden should be ok.

[nirvana]

if you still want to calculate surface area probably easiest way is to get a piece of paper and draw a grid up to whatever scale you choose.
then put brake pad on it trace it and count the squares.
might not be accurate but probably close enough to get an idea.