The AW11 Brake Upgrade Thread

[Brendan]

my random input:

At my last wakefield session with scott, we both have stock brakes both with project mu hc+ pads.

Only difference was he has the old dba rotors and i have the rda's because dba dont make them anymore.

My brake temps were much higher than his, and resulted in burning my fluid and even possibly my front pad compound too... He was also braking harder than me as he has more speed...

Technical problem maybe? i rebuilt the calipers b4 i put them in. they seem in good order.

[Duk]

here's a list of the dimensions from the DBA catalogue

Exacery what I was after! Prus rep for you!

Mmmmmmmm 6mm thinner than my ebay sourced information. My surprise is massive

[TooF]

brendan: were your rotor temps higher (tested with a pyrochromatic paint) or you were just finding they were overheating and failing sooner ?


a couple of things to chase after. difference in fluid, i know scott uses rbf600 (im the same and never have had grief)

how old is your fluid ? RBF600 (and most others) are hydroscopic so they will absorb water. once there is water in the fluid the boiling temperature is significantly less.

also you will find once a fluid has been overheated once its boiling temperature later tends to be reduced.

if the calipers wernt properly bled then air bubbles in the caliper will also aid in the fluid boiling easier.

that said if it was rotor temperature youve measured there are a couple of explinations.


off the top of my head the DBA rotors are directional in the venting which means they work better L/R becasue the internal fins are curved which "pumps" more air though them cooling them better. the RDA ones arnt as good in this aspect and are jsut straight vented internally.
i assume your rotors are slotted to allow outgassing on the pads ?

have you got HC+ all around ? if you only have good pads in the front then the backs may have long overheated and faded to nothing causing the fronts to do all the work hence their overheating.

are they grabbing causing the pads to rub when youre not on the pedal causing overheating ? do you have the springs in there that seperate the pads off the rotors ?

just tossing out ideas

[MR22ZZ]

the venting on the rotors is not directional

the slotting however is.

[TooF]

are you sure ? i know some of the DBA units have directional venting.. obvisouly yes the slotting is but im sure some have directional venting

[MR22ZZ]

My DBA-743s for my AW11 came with no indication of left or right on them, but the slotted rotors I ordered for the Sportivo did.

here's the DBA 'kangaroo paw' vent design

[TooF]

but when you look down the vents of the rotor are they straight or are they curved ? i know the rda ones are straight but ive got a feeling the dba ones are curved

[MR22ZZ]

see edit in previous post

[TooF]

yeah but the aw11 rotors were not kangaroo paw. only their newer and high volume discs were kangaroo paw the older ones are all traditional vented. the kangaroo paw is much better but never avaliable in the aw11 disc

[MR22ZZ]

ahhh, fair enough.

no idea then, I don't have DBA AW11 rotors to be able to check

EDIT: again a quick search shows no difference in the product codes of the unslotted rotors.

[Joshstix]

The nut behind the wheel has a massive impact on brake temperature.

I've seen instances where a driver comes in with the brakes literally on fire complaining that the brakes are worthless and holding them back. Then the car go out with a more experienced driver and run significantly quicker tiems with zero brake problems.

[aw11gte]

Exacery what I was after! Prus rep for you!

Mmmmmmmm 6mm thinner than my ebay sourced information. My surprise is massive

Sounds like your doing the same as me here. Ive got the 22v sw20 rear calipers ready to go on but dont want to make the spacer and get the longer studs.
What rotors have you decided will fit straight on?
Ive been searching for ages, there are a couple of nissan ones and some VW ones that look promising, but taking my spare hub into the parts shop to see if it will all fit aint gonna happen.

[Duk]

Sounds like your doing the same as me here. Ive got the 22v sw20 rear calipers ready to go on but dont want to make the spacer and get the longer studs.
What rotors have you decided will fit straight on?
Ive been searching for ages, there are a couple of nissan ones and some VW ones that look promising, but taking my spare hub into the parts shop to see if it will all fit aint gonna happen.

My issue atm is finding 22v calipers, so there is still that bridge to cross.
Alternatively I'm thinking of using my old SC front calipers (have ST185 GT4s at the front) and having a closer look at what I can use. The ZZW30 rear discs look too thin. If they were 22mm thick I would be looking real close.
Most AW11 owners would have seen this http://www.mr2mk1club.com/Bigbrakes.html, unfortunately it doesn't seem Australia got any VW/Seat with those spec brakes, so getting those discs could be interesting.
Maybe a pair of rotors and custom hats, but I'm trying to keep the costs down.

Edit: Do DBA supply rotors undrilled?

[Brendan]

hmm i also have factored in the nut behind the steering wheel and wouldn't disagree that im to blame hehe.

Temps were measured via scotts infa red gun.

[aw11gte]

My issue atm is finding 22v calipers, so there is still that bridge to cross.
Alternatively I'm thinking of using my old SC front calipers (have ST185 GT4s at the front) and having a closer look at what I can use. The ZZW30 rear discs look too thin. If they were 22mm thick I would be looking real close.
Most AW11 owners would have seen this http://www.mr2mk1club.com/Bigbrakes.html, unfortunately it doesn't seem Australia got any VW/Seat with those spec brakes, so getting those discs could be interesting.
Maybe a pair of rotors and custom hats, but I'm trying to keep the costs down.

Edit: Do DBA supply rotors undrilled?

This is a troubling problem, i jumped at the chance to get my rear calipers as i know they are hard to come by. I just dont want to have the spacer and the longer studs, call me paranoid. 20mm for the spyder rotors isnt bad, stock aw11 rears are only 12mm or something crap, but will still place them too close to the carrier bracket.