misfit2009

So since I went to the Nurburgring and turned a pair of brake pads to smoke (literally) and managing an 8:38 (all the good bits of different laps - it was very busy) i got sick of my crappy rear discs.I already had drilled and grooved discs but that didnt go too well:




So having remembered a Youtube video i'd seen years ago i decided to try my own homebrew vented rear discs:




Which judging by a brake temperature monitoring system i'd made was actually worse than drilled and grooved discs.. I thought the radially drilled holes would be much better than axially drilled holes, but live and learn using 4 of these:

https://www.ebay.co.uk/p/?iid=292090...&crdt=0&chn=ps

4 of these (i made them at work)




And an Arduino UNO i had real data to use and I'd always wanted some aluminium belled brakes - there were some on eBay but £600+ for 2 fronts, i don't think so! So i set to work making my own

By this point my stone shields were well past saving anyway, so they got taken off and thrown away to make room for my temperature monitoring system in the first place.




Whilst I was at it i decided to make vented rears - I'd always been curious on the effect of losing thermal capacity vs increasing cooling capacity.. but they did end up very thin!



And for shits and giggles i decided to anodize them - i'd bought the gear to do it years ago but not actually ever used it. Also since no one likes rusty discs i decided to spray them black with VHT (high temp) paint:



Next i fitted them - the front pad carriers needed some clearance filing onto them but that only took 10 minutes each - i cant imagine its affected how strong the carriers are or anything so I'm sure it'll be fine:



Gotta admit they look pretty bling when fitted though




(I cant afford germanium glass for my brake temperature sensors so i couldn't wash my wheels, i can live with it) so i took it out and got myself some data on the effectiveness of my brakes' cooling efficiency - and i've made them into YouTube videos for your approval: (ignore the rear left, it was binding because my handbrake cable was too tight)


^^ that was a run with both right hand brakes being drilled and grooved. Interestingly to me the drilled and grooved fronts performed better (in terms of cooling capacity) than the standard none drilled discs - i had expected the plain discs would cool more effectively because the holes drilled through to the vents would ruin the airflow because you're putting a leak in the Venturi effect (live and learn again i guess!).

The rear drilled and grooved discs performed a little better than plain discs - they warmed up roughly the same as the radially drilled rear discs (second picture) i'd made, but also cooled faster - although the test on the radially drilled discs i've not recorded,

So it was time to test my new discs:


The cooling capacity of the rears is phenominal! They warm up faster than the solid rear brakes, but the cool down time is much better, and they stay much closer to the temperature of front brakes, both warming and cooling - i do cook the brakes much more on this test (because that rear left was getting so hot on the previous test and i was trying to get sensible numbers from my left rear and the temperature limit of the sensors was 380 degC) but notice how much closer the rear temperature is to the temperature of the fronts!


Since then i decided to take them out on a torture test (off camera ) which from experience is much more harsh on brakes than the Nurburgring.. and managed to knacker my crank bearings (I'm half way through stripping the engine but i've found a lot of flakes of bearing :'( ) and they've performed flawlessly (so far, but also they've got very limited mileage on them as yet)

Upshot of the whole debacle : Drilled and grooved discs are better than standard, and my discs are better than drilled and grooved.

If anyone would like a set (all 4) of my discs i can make them for £600 plus postage - no warranty expressed or implied, you're buying 4 S2000 brake disc paperweights and if you use them for any other reason than weighing down paper your car will spontaneously combust, your arms will switch sides, you'll forget your father's name is and your penis may start growing inwards

starchland

Did you paint the rotor surface? How does this not affect the pad?

misfit2009

I did and it just burns off within seconds (and goes all over your wheels!)

freq

I don't even homebrew my own beer let alone brake discs.

Slowcrash_101

Are they iron rotors?

misfit2009

Yeah standard iron rotor with ally bells (suppose i should point out I'm an engineer by trade)

Mike RT4

What thickness were the rear discs originally and what did you get them down to?

I'm surprised that seeing as you went to such lengths, you didn't take less off the rear discs and do the "Urge" mods to the rear calliper carriers for disc longevity?

misfit2009

They were 18 with a minimum of 16 but designed for the front of a Toyota hilux (big JDM (maybe you guys have them) 4x4 tank) so they should do quite nicely for the back of an s2000

Never heard of the urge mod and a few searches haven't revealed anything, have you got a link for me?

cahooa

Either the hub or discs should be slotted to allow for the difference in thermal growth between the iron and aluminum. I don't see that on your design. I'm also not seeing any sort of locking hardware? What grade bolts did you use?

jwzimm

I would be very careful with offering these for sale. You are dealing with critical hardware to the safe operation of the vehicle. You could be held liable should a design defect result in disaster.

As pointed out, you may not be fully versed in the design aspects of braking hardware. One of the most critical thinks in a two piece rotor is how to allow for differential thermal expansion between the aluminum hat and the iron disc. If the two are not able to move relative to one-another the stress build will lead to cracking and eventual failure.