Brake Upgrade

[maccattack]

I have been finding I am running out of brakes on track days in my 33 GTR - spongy pedal heading towards boiled fluid.

At this stage I have standard Brembo calipers and lines running with DBA 5000 series rotors.

I need some advice from those in the know regards upgrades.

Now from what I have read, thermal capacity is the key here - (please correct me if I am wrong).

My question is this - should I be looking at changing lines to braid and increasing my air ducting to the brakes

before I look at larger brakes?

Are standard Brembos up to the task if the airflow to them is increased?

Thanks

Peter

[Beer Baron]

definately look at ducting before spending up on bigger gear. if you still have the stone guards there, remove them first. then look at getting some ducting in there. braided line wont help with cooking fluid, but it is a good upgrade to do anyway. also what pads are you using?

[Resin]

after how many laps is it going spongy? You could always do a few cool down laps.

What pads are u running?

What fluid are u running?

R33 gtr's already have some form of ducting to the wheel well which could be extended closer to the disc.

[djr81]

I have been finding I am running out of brakes on track days in my 33 GTR - spongy pedal heading towards boiled fluid.

At this stage I have standard Brembo calipers and lines running with DBA 5000 series rotors.

I need some advice from those in the know regards upgrades.

Now from what I have read, thermal capacity is the key here - (please correct me if I am wrong).

My question is this - should I be looking at changing lines to braid and increasing my air ducting to the brakes

before I look at larger brakes?

Are standard Brembos up to the task if the airflow to them is increased?

Thanks

Peter

First port of call is to increase the airflow to the hub & the rotors. This will reduce the temperature of the rotors/callipers etc between stops. Try the www.nismo.com.au site for some brake ducts. Not sure if they have finished the bits for GT-R's, but worth a try.

The second port of call is probably to throw the DBA rotors into the nearest scrap bin. Get yourself a rotor that has internal vanes that actually pump air - the DBA just has pillars that do approximately SFA. This will work with your ducts to keep things cool. Try Mu Secret, Harrop, Endless.....

Lastly, there are better callipers around than Brembo. Particularly some which have what are referred to castlellated pistons. It looks like a tower on a castle - hence the name. This reduces the amount of heat transferred from the rotor & pad to the fluid in the caliper. Other things like external cross over lines help too. Not sure about titanium backing plates for the pads - I suspect this is just a bit of wank factor.

The thermal capacity of the rotor is proportional to the weight of the rotor. But, remember that the amount of heat put into the rotor in the braking zone will not change if you go to a larger rotor. Nor, if done well, should the weight of the rotor increase markedly. So the difference in storage capacity only changes if you select a heavier rotor - something it is worth avoiding.

Upshot - more ducting + better rotor. In that order.

Edited September 18, 2007 by djr81

[maccattack]

Thanks for the fast replies so far guys.

Currently I am using the Hawk Race pads. Moved to these after Endless changed compounds and prices.

Find they are very good at holding up - fairly savage on rotors though.

Fluid is Motul Dot 5.

They car has a reasonable amount of mumbo so it takes a fair bit of pulling up.

Stone guards are gone, but still gets pretty hot at around 7-10 laps (spongy).

I have lost brakes previously by not letting them cool down enough between sessions.

Only ducting at the moment is standard.

My initial thoughts are to increase this fairly substantially before going to a bigger brake set (cheaper too).

Hadn't thought too much about the rotors before now.

I'll have to have a look into them.

Thanks

[djr81]

Well if you are using DOT 5 fluid then that is your answer to why your pedal is spongy. GET RID OF IT.

Replace it with Motul RBF600 which has a higher boiling point & gives you a better pedal feel. Cheaper too. Basically all things to all people.

[Resin]

when u say dot 5 .......u mean dot 5.1 i take it?

Edited September 18, 2007 by Resin

[hrd-hr30]

QR is very hard on brakes. The ducting is a good idea, and looking at the fluid. how old is the fluid in the car? It does go off and needs to be replaced fairly regularly. Particularly in humid climates like Brisbane. Flushing it with a 600deg fluid is probably the solution.

Penrite make a 600 degree fluid that worked fantastic in my GTR at QR. And its half the price of Motul stuff. Autobahn stock it. About $16 for a 500ml bottle IIRC. It also gave me the best pedal the car ever had. 2 bottles is normally enough to completely flush the old fluid out.

definitely worth trying before looking at more expensive brake upgrade options.

Edited September 18, 2007 by hrd-hr30

[maccattack]

Thanks Harry,

I'll definitely look into it.

I have in the interim got a price on Mu Secret rotors ($900-00) for fronts and Endless ($1950-00) for fronts - FARK!!!!

Spoke with UAS who swears the only way to go is an upgrade - of course they are selling me their merchandise.

Still a little bemused but think I will do the staged approach and see how it goes.

Fluid- ducting - rotors - 62 piston calipers.

[Roy]

I think if you are getting 7-10 laps out of it then there are a few small things that can be done if the braking is marginal.

LOl, the obvious one is ducting... a not so obvious one could be wheels. Talking to a guy that works for a Ford team, wheel type affects brake temps. So if you have been thinking about a wheel upgrade then something to consider when shopping.

Try a cool down lap on the 4-5th lap just to give everything a brake (unless its a race of course).

[tacker]

Not sure that you will need to go to new brakes just yet. What type of tyre are you running? if you are running a street tyre then your best sticking with the standard caliper. Cant comment on the DBA rotors as i have never used them.

There is solid advise in the comment above best fluid you can afford, and more ducting which i must say was the difference mine fading and not.

http://www.skylinesaustralia.com/forums/in...ducts&st=20

[T04GTR]

if its dot 5. thats silicon based. wich means all your rubbers will be f**ked. hence spongyness. unless you have had all the rubber seals in the master cylinder changed and calipers rebuilt to suit silicon fluid.

hopfully they arnt completly gone. if the flid has boiled. the brembo writing on the caliper should now be a light to meduim brown colour. if its still white then its the seals going soft.

yes rbf600 or penrite syn brake fluiid is the best value. a caliper upgrade is a good idea. but to do CORECTLY you wont have change from 4-5k

[maccattack]

Thanks so far guys - great feedback.

I am running 255 semi's (RE55's) all round with Work Emotion Cr Kai wheels for the track.

Pretty sure the fluid has been top of the line Motul as we (ie: the mechanic) changed me over to the better fluid approx 12 months ago (after the brake loss incident).

I haven't ever rebuilt or serviced the brakes since I have had the car. Maybe that is part of it????

[Duncan]

Well original brake lines will be nasty and spongey by now but that only affects pedal feel not the ultimate braking power.

Basically....the brembo calipers are pretty average, and if you are looking at spending $2k on rotors you are much better off speding $2k on the g4 8 piston set up - comes with calipers, 2 piece discs, braided lines etc. Bolt it all on, good flush with motul rbf600, run brake cooling ducts and you should have all the brakes you ever need.

[tacker]

Duncan,

prepare ye self for the back lash

[maccattack]

I had been reading the reviews on here for the G4's / D2's / KSports and they all seem pretty good for the money.

I had been looking at the AP Racing big brake kit from UAS which I know is good stuff. I also know it aint cheap.

My only concern with the cheaper sets is longevity. It would appear that there is no probs initially with their stopping power,

but being a lower quality alloy, is overflexing a problem and what effect will this have on the callipers long term?

[ferni]

How much power do you have mac? I'm running about 300rwkw on RE55s.

I have a similar setup to you... Stock Brembos on my R33 GTR, DBA5000 rotors, RBF600 Fluid, DS3000 pads, removed stone shields, Braided lines.

I killed my brakes when i was running DBA4000, Stock lines, RBF600, RB74 pads, still had stone shields on at Winton a while ago

http://ferni.net/photos/Cars/0607_Killed_m...akes_at_Winton/

You can see i turned my Brembo sticker orange like T04GTR said above.... what does this mean exactly? I have a rebuild kit ready to go through but haven't got around to having it done yet.

After that i changed to the DBA5000s/DS3000s/braided lines, removed stone shields and have done Sandown and PI since, and it seems to be ok - but i only do 3-4 laps in a session, not 7.... I don't think it would last that long.

I'm trying to get John@UAS to make some ducts/deflectors for R33 GTR which i think will help a lot. I found out the other day that Vspecs have some stock brake deflectors (smallish) and non-vspec don't.... Email him tell him you want some as well, the more people that do the more likely he will be to make some

[maccattack]

Andrew,

Probably about 375awkw at the moment.

I'll shoot john an email today. Hopefully that will be a nice start to cooling them down.

Looked at you photos - S H I T. Now that what I call rooted rotors. They must have felt like crap while you were driving.

[Roy]

Ferni, Didnt that happen when you ran out of pads?

If you make up some deflectors that go on your castor rods, then run some neat ducting....you can have a play and do as little or as much as you like. But with the power you have...well you have V8 Supercar power, more weight, less corner speed...so if you do the math its a lot of kinetic energy you are trying to slow

[ferni]

Yeah that happened when i ran out of pads, but the brake pedal was hitting the ground before i ran out of pads, and then just to throw something else in, the pads fell apart under the extreme heat and i ended up metal on metal Then i had to drive home 2 hours like that... that was interesting... it was mostly highway driving at least...

You have a fair bit more power than me Peter... I really think you'll struggle to keep stock brakes with that kind of power... But cooling/ducting will help no matter what brake setup you have. And I guess the good thing for me is that if you can make your stock brake setup work then i should have no troubles with my measly 300kw....

I really don't know how you're getting more than one or two laps without running the pedal hitting the floor... Do you still have the stone shields? I think that was probably the biggest difference to me (that and a master cyl stopper).