Author Topic: Disc brake theory.  (Read 13441 times)

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Offline Luke

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Disc brake theory.
« on: Aug 1, 2010, 09:56AM »
I had my Bluebird out at Mallala a few weekends ago. I had made a point before heading out to make sure I had the best brakes possible on it, after doing some research I found that the highest rated pads that I could fit into my calipers were QFM 500. Rated 100 Degrees higher than the bendix heavy duty pads. However after 32 laps at Mallala, the pads were gone, down to bare metal causing a rather high speed incident and requiring a change of underwear.  ::) I sent the pads back to QFM and they actually gave me my money back, which I didn't expect but what I need to know now is what to do for the next track day.


This picture was taken from video, early in the day, long before I knew anything was wrong. Looks to me as if the rotor isn't actually hot but the caliper is.

At no stage during the day did I experience brake fade, which gave me confidence that I had picked the right pads, right up until they failed. I am hoping this means that my caliper and rotor combination (standard U13 attesa) are capable of handling the braking if I can have some higher quality pads custom made. Vithy has let me borrow a set of GTR calipers to test fit, these obviously would solve all my problems as quality pads are readily available, but I only want to go down this road if it is absolutely necessary.I really like my 15 inch wheels for everyday driving.

So my question is, with the correct pads, will my current brakes be able to take the punishment or am I doomed to having to upgrade to larger calipers and rotors?



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Offline SSS

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Re: Disc brake theory.
« Reply #1 on: Aug 1, 2010, 10:56AM »
What friction coeffiecient and temp are these qfm 500's rated to? couldn't find anything on google.

Do you have the twin piston fronts or single?

Personally I think you need to go for something from EBC (Red stuff pads) or Project Mu (Type NS or B Spec pads), then again some Hawk Blue's or the like couldn't hurt if the $$$ allow for it.


Offline Vithy

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Re: Disc brake theory.
« Reply #2 on: Aug 1, 2010, 12:41PM »
Wow ive never seen it like that before, this is the first photo ive ever seen that the pads are glowin and the rotors are not :S that to me is like fuckin wierd :S

Did they fail or wear out?? Would it be be worth investing in some high fuckin temp gloves and changing pads mid way though the day?

Apart from testing a set or a couple of sets of more expensive pads and seeing if the problem is the same and how well they go ect. I guess u only move after that is bigger brakes or calipers. To my understanding a properly working brake system both the disc and the pad should wear a little when being used, if the pads are getting that hot it makes me think that they are the only ones wearing but again i dunno a whole lot about brakes this is just wat my brain is saying so dont take it as bible. If the rotors were getting super hot i would of said duct the brakes to try and run them cooler, i dunno if in this situation it would help much.

I take it my GTR calipers dont fit under ur 15in rims, another option you have there are 4 pot calipers that are used on turbo skylines that arent gtr which might fit if ur lucky, their still big but not a big as the GTR calipers i dont believe. My mate runs them on his street cefiro 4 pot fronts and 2 pot rears, but dont get to excited tho coz he runs a spacer and 16 on the front maybe 15, next time i see him ill confirm, but wid the bluebird style of rims u might get lucky and they will fit under. I think the space is just there for extra track.

And about them GTR calipers from what ive been told they are the same 4 pots as 300zx run and the s14 silvia.
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Offline lgee

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Re: Disc brake theory.
« Reply #3 on: Aug 1, 2010, 02:39PM »
QFM 500 is rated to 500 deg, wow that is some serious brake wear, didnt wear them out that much at phillip island

Offline chr1S

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Re: Disc brake theory.
« Reply #4 on: Aug 1, 2010, 06:38PM »
I personally think that QFM are one of the better pads on the market compared to the rotor munching red stuffs, by looking at the photos, it looks like something has gone bad with the brake pad and the bonding to the backing plate causing the excessive heat.

How did you install these pads?
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Offline Luke

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Re: Disc brake theory.
« Reply #5 on: Aug 1, 2010, 08:54PM »
What friction coeffiecient and temp are these qfm 500's rated to? couldn't find anything on google.
Do you have the twin piston fronts or single?

They are rated to 550 degrees, which is why I bought them, they were the highest rated pads I could find that will fit my calipers. Standard Attesa's are 2 pot fronts, and use maxima pads with a few mm nicked off each end with a grinder. Because they are maxima pads, no-one makes high performace pads for them. My choices were either these or bendix HD. I would have gone for the bendix but they are only rated at 450 degrees. In Hindsight they may have been the better option.
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Offline Luke

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Re: Disc brake theory.
« Reply #6 on: Aug 1, 2010, 09:02PM »
Wow ive never seen it like that before, this is the first photo ive ever seen that the pads are glowin and the rotors are not :S that to me is like fuckin wierd :S

It's hard to tell from the photo, but it may not be the caliper glowing, it may be the pads on fire, notice how it runs around the caliper down the bottom a little.
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Offline Luke

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Re: Disc brake theory.
« Reply #7 on: Aug 1, 2010, 09:06PM »
I personally think that QFM are one of the better pads on the market compared to the rotor munching red stuffs, by looking at the photos, it looks like something has gone bad with the brake pad and the bonding to the backing plate causing the excessive heat.

How did you install these pads?

Had my rotors machined, put new pads in. Did about 100km of country driving before I hit the track.
Jason reffering to the OzVR4 Forum... "Even their forum is slow" "FJ20.com on the other hand, yep that S12 does Mono's"

Offline Vithy

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Re: Disc brake theory.
« Reply #8 on: Aug 2, 2010, 01:55AM »
It's hard to tell from the photo, but it may not be the caliper glowing, it may be the pads on fire, notice how it runs around the caliper down the bottom a little.

hahaha flaming pads! nice!

r33 turbo, non gtr calipers are the ones im thinkin off im pretty sure
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Offline Luke

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Re: Disc brake theory.
« Reply #9 on: Aug 4, 2010, 10:34PM »
Laurence, what brakes do you run at Phillip Island?
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Offline lgee

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Re: Disc brake theory.
« Reply #10 on: Aug 5, 2010, 09:30AM »
well i was running attesa twin spot calipers with QFM 500 pads as well but i did not have that drama, but the brakes at the island get plenty of time to cool, winton is a different dog, i have not run my car at winton yet, does you car have ABS?. i have not run it at the island yet with the 4 spots in it and to be quite honest it still has the Protec sports pads that it had when i got them off adam. you should buy my upgrade kit, Micka8 has them and he now runs 325x30 front rotors.
« Last Edit: Aug 5, 2010, 09:32AM by lgee »

Offline noss

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Re: Disc brake theory.
« Reply #11 on: Aug 5, 2010, 10:19AM »
not sure if it was posted up already, but what rotors were you using? i dont see anywhere it was mentioned other than they were machined with 100km on them. if they're not at least slotted upgrade asap.

if they're not slotted, buy a set of the r32 gts4 rotors, they're the same dimensions as the U13 import rotors but available off the shelf, no machining, no modification, no buying blank and having drilled to 4 stud. i was running dba kangaroo paw slotted in my setup. obviously i didnt end up racing in the pinny, but its worth a look if you're not running them. the skyline brakes the only upgrade is the extra 2 pistons, the rotors are the same size but need to be machined down to fit because of the mounting brackets for the calipers.

also you can indeed get dba green/yellow/red for the maxima, they're the J30 maxima yeh? problem is we live in australia and you know, commodore/falcon or you get no parts >:( you will most likely have to order from the usa. the parts are:

ebc green: DP2775
ebc high friction: DP4775R
ebc red: DP3775C
ebc ultimax: UD430

or if i was wrong and its the A32, then your part numbers are:

ebc green: DP21752
ebc high friction: DP41752R
ebc red: DP31752C
ebc ultimax: UD653


not saying use EBC over QFM, but the option is definitely there.

and i know off topic, but the U12 pintara front brakes are the same as the R31 skyline, your pad options are:

ebc green: DP2792
ebc high friction: DP4792R
ebc red: DP3792C
ebc ultimax: UD485


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Offline SSS

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Re: Disc brake theory.
« Reply #12 on: Aug 5, 2010, 10:44AM »
Luke, get rid of the backing plate behind the rotor too.

Offline noss

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Re: Disc brake theory.
« Reply #13 on: Aug 5, 2010, 04:36PM »
or keep the backing plates and install diy brake ducting:

http://forums.pelicanparts.com/porsche-911-technical-forum/471353-budget-diy-brake-cooling.html

just need the flex hose to run to the front bar.

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Offline Vithy

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Re: Disc brake theory.
« Reply #14 on: Aug 5, 2010, 06:56PM »
if they're not slotted, buy a set of the r32 gts4 rotors, they're the same dimensions as the U13 import rotors but available off the shelf, no machining, no modification, no buying blank and having drilled to 4 stud.
would these disc work wid gtr calipers or are they too thin??
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Offline Luke

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Re: Disc brake theory.
« Reply #15 on: Aug 5, 2010, 09:02PM »
not sure if it was posted up already, but what rotors were you using? i dont see anywhere it was mentioned other than they were machined with 100km on them. if they're not at least slotted upgrade asap.
Running the standard U13 Attesa front rotors.

if they're not slotted, buy a set of the r32 gts4 rotors, they're the same dimensions as the U13 import rotors but available off the shelf, no machining, no modification, no buying blank and having drilled to 4 stud. i was running dba kangaroo paw slotted in my setup. obviously i didnt end up racing in the pinny, but its worth a look if you're not running them.
Had a look on the DBA website, but couldnt find a listing for the R32 GTS4, is that the only skyline of that era with 4 stud?

the parts are:
ebc high friction: DP4775R

Where di you find the information for this? I Have found a US online store that has them for far less than I was expecting to pay, if I can confirm that this is defiantely the correct number then I will order them.
http://summitracing.com/parts/EBC-DP4775R/Application/?prefilter=1

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Offline noss

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Re: Disc brake theory.
« Reply #16 on: Aug 6, 2010, 11:11AM »
i got the part numbers from ebc's online catalogue and then confirmed on their pdf (65mb file!!)

pdf catalogue:
http://www.ebcbrakes.com/Assets/2010-usa-automotive-catalog.pdf

online catalogue:
http://ebcbrakes.iwebcat.com/

the skyline might be listed as the 'type-m' which is what i always knew it as, but i'm pretty certain i ordered gts4 brakes. actually.. my mistake, not r32, its r33. there was a 1 week wait when i ordered mine cause even though its an off the shelf fitment, they dont keep it in large quantities. here are the details so you can compare:

dba u13 bluebird (aus model):
"dba-u13-bluebird"

dba r33 gts4 skyline:
"dba-r33-gts4"

hope that helps you out!


would these disc work wid gtr calipers or are they too thin??

you will still need to machine down the disc to the smaller diameter. the issue is not with the discs, but the slightly different mounting location of the GTR caliper.

they might be too thin as well, the gtr rotors are either 28 or 30mm from memory.

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Offline dozer

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Re: Disc brake theory.
« Reply #17 on: Aug 12, 2010, 06:22AM »
just put some r32 brakes on it!!!! and slotted rotors.
i'm running them with bendix ultimate's but want to change pad to pagid.
the ultimate's last a meeting and gave me enough to drive around after on
but thats with bigger brakes then yours......

Offline shimeixiaoxiao

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Re: Disc brake theory.
« Reply #18 on: Oct 21, 2010, 04:56PM »
Personally I think you need to go for something from EBC (Red stuff pads) or Project Mu (Type NS or B Spec pads), then again some Hawk Blue's or the like couldn't hurt if the $$$ allow for it.
Oh I love all of these!moncler

Offline Luke

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Re: Disc brake theory.
« Reply #19 on: Apr 4, 2011, 11:44PM »
So... I went with the R33 GTS4 rotors.. perfect fit thanks noss. However, the EBC Yellows for a A32 Maxima from the states do not fit. This would explain why they are not available in Aus... We made them fit, cut and welded the ends of the backing plate from the old pads onto them.

In any case... cooked them again... right down the metal and scored my new discs. Thinking I have issues with my rear brakes now, getting new pads, flushing the fluid... and changing my front calipers so that I can actually get some pads that work.
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Offline mendezcr

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Re: Disc brake theory.
« Reply #20 on: Apr 5, 2011, 08:52AM »
Jummm... r32-r33-r34 brakes?... Nice upgrate... I was thinking in using the 300zx calipers on my HNU12.....

Hope that upgrade work fine Luke.. Keep update to see if they worked...  ;D

Offline Kranzy

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Re: Disc brake theory.
« Reply #21 on: Apr 5, 2011, 01:15PM »
R32 and r33 are basically the same. Both will work on a u12 unsure about abs though.

I have done the r32 upgrade.
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Offline noss

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Re: Disc brake theory.
« Reply #22 on: Apr 5, 2011, 07:38PM »
i think pedro has done the 300zx upgrade, but you'd have to check

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Re: Disc brake theory.
« Reply #23 on: Apr 6, 2011, 12:06AM »
300zx are the same as the r32.

There are 3 types available, you just have to make sure you have the same calipers.

There is a 30mm aluminum caliper.
A 30mm iron caliper and a 26mm ( I think) iron caliper.

I had a guide somewhere of how to tell the difference. I'll see if I can find it online again.

The size refers to the thickness of the rotors.
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Re: Disc brake theory.
« Reply #24 on: Apr 6, 2011, 12:13AM »
I lied, there are two aluminum calipers and one iron caliper.

See this link for how to tell the difference. Also good guide on upgrading.

http://importnut.net/300zxbrakeswap.htm
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Re: Disc brake theory.
« Reply #25 on: Apr 7, 2011, 07:49PM »
This might help ya! Turns out some of what i mentioned to you today is right and some of which is wrong, guess its down to how much detail and measurement ppl actually go into as to how accurate the information is.....

http://www.sr20tuning.com/brakes.html
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Offline Luke

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Re: Disc brake theory.
« Reply #26 on: Apr 7, 2011, 11:55PM »
Yep, those GTR brakes are deffs bigger than the rest Viv. Cant even git my 16's over them, not enough offset. I'm gunna stick to my guns on the Bluebird calipers... Went through the bendix catalogue with Jason... found that Muruno Pads are a very smilar size to the maxima pads, but come in a better heat rating. Also, Checked and found a pad for falcons / commodores that is too big in all aspects that I can cut down, will mean I can import proper race grade pads and fit them up.
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Offline Craazy

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Re: Disc brake theory.
« Reply #27 on: Apr 9, 2011, 05:41PM »
Check out Ksport for U13 Altima front brakes. 6 and 8 piston kits with 300 - 400mm discs.......

cheap as chips and direct bolt on


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Offline Vithy

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Re: Disc brake theory.
« Reply #28 on: Apr 9, 2011, 08:55PM »
Check out Ksport for U13 Altima front brakes. 6 and 8 piston kits with 300 - 400mm discs.......

cheap as chips and direct bolt on

how big are they? how big a rim would u need to fit them bad boys under? how easy are pad to get for them??
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Offline Luke

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Re: Disc brake theory.
« Reply #29 on: Apr 11, 2011, 09:12AM »
Check out Ksport for U13 Altima front brakes. 6 and 8 piston kits with 300 - 400mm discs.......

cheap as chips and direct bolt on

Your not reading the whole thread
Jason reffering to the OzVR4 Forum... "Even their forum is slow" "FJ20.com on the other hand, yep that S12 does Mono's"