Are You Cracking Dba Rotors?

[Sydneykid]

LOL, dont discount whoever is drivng your cars actually knows how to brake

I cracked my near new 4000s doing a half mile run where i didnt get a chance to warm the brakes, and had to stop from god knows how quick, about 210km/h i think. And the runway didnt have a lot of run off space in the brakign area so you had to really jump on them to slow the car to a complete stop. Car had to do that 4 times with about a 45 min rest between runs....so i suspect thats what caused dramas for me. Here is the thing, my car is being used for these sorts of events more and more, and has different stresses on the car to the usual track work

Some of the more subtle tricks;

On the GTR's we jack them up and warm up the brakes (front and rear) and the transmission before every outing. They never leave the pits with cold brakes.

On a RWD you can only do the rears, but it is better than nothing. FWD obviously works well too.

We stick covers on the wheels to retain the heat between runs, helps warm up the tyres as well as the brakes.

We never pull in to the pits and sit there chatting to people through the window, while the hot spots do their job. Every track day I see it, drives me crazy.

Temperature paint is your best friend, use it often.

Don't buy the highest temperature brake pad you can find, anything much over 750 degrees is going to kill a cast rotor.

On the pit outage the drivers know to drag the brakes, left foot braking while accelerating, helps warm up the tyres as well as the brakes.

Cheers

Gary

[Angus Smart]

yes, but do you know for sure which ones or how to communicate with them to order their gear? they seem to be the sticking points that Angus and I have encountered. i reckon it's either Biot, Rdd or Dixcel. Close?

i never checked up on rdd, didnt know about that company but i think they are the one! i will have to measure my rotors when i get home to make sure but they are pretty close to what i think i have at home.. i recall a 343 number as i can remember the disc size a bit of an odd number.

http://rdd-brake.com/f50.htm

Edited January 10, 2008 by Angus Smart

[djr81]

Well in what will come as a massive surprise to people I just found another cracked DBA4000 rotor on my car. Fkn yay.

[Sydneykid]

Well in what will come as a massive surprise to people I just found another cracked DBA4000 rotor on my car. Fkn yay.

Other than what I have posted above, I have no idea why some guys suffer badly and some don't. As a comparison, we used DBA5000 series rotors for the Bathurst 12 hour with Brembo calipers on a DC5 Integra, zero cracks, probably good for another couple of hours. Maybe you should try some 5000 Series, they may suite your application better than 4000's.

Cheers

Gary

[Roy]

You cant buy 5000s for the R32. And if i was upgrading to a caliper that runs a larger rotor then the GTR std i wouldnt bother with a DBA 5000 even...why? Because fark em. The BS you when you approach them with a genuine problem/concern.

Can you take it off and take a few pics. ANy tint of blue off the area that the pad comes in contact with, on either the inner or outer face of the rotor. Are you running any sort of brake ducting? What pads are you running and also how old etc are they.

Buy some cheap F40/50s as i have all the drawings now to mount them on 324, 343, and 355mm rotors. I am now running my F40s on 324mm after having an accident with a flight of stairs and my 343mm rotors

[djr81]

Other than what I have posted above, I have no idea why some guys suffer badly and some don't. As a comparison, we used DBA5000 series rotors for the Bathurst 12 hour with Brembo calipers on a DC5 Integra, zero cracks, probably good for another couple of hours. Maybe you should try some 5000 Series, they may suite your application better than 4000's.

Cheers

Gary

My car is an R32 so I can't get any 5000 series loving.

[djr81]

Can you take it off and take a few pics. ANy tint of blue off the area that the pad comes in contact with, on either the inner or outer face of the rotor. Are you running any sort of brake ducting? What pads are you running and also how old etc are they.

Buy some cheap F40/50s as i have all the drawings now to mount them on 324, 343, and 355mm rotors. I am now running my F40s on 324mm after having an accident with a flight of stairs and my 343mm rotors

I'll see if I can get some photos sometime soon.

The thing has been in the shed neglected for a few weeks now so any short term surface finish will have been lost.

It is a rear rotor, I presume it is on the outer face, but until I have a look I can't be sure. No brake ducts, DS2500 pads. Rotors aren't that old, but have done a few events. They aren't worn by any measure, although I will put some micrometers on them when I get a chance.

Just sell me your F40's Roy & everything will be allright.

Edited February 14, 2008 by djr81

[Sydneykid]

Personally I would get a set of calliper adaptors off John (UAS) and use the 343 x 32 mm 5000 Series rotors with the standard callipers and set of Hawk HPC60 pads. That's about as much braking performance on a GTR as an R type tyre can handle.

Cheers

Gary

[djr81]

Personally I would get a set of calliper adaptors off John (UAS) and use the 343 x 32 mm 5000 Series rotors with the standard callipers and set of Hawk HPC60 pads. That's about as much braking performance on a GTR as an R type tyre can handle.

Cheers

Gary

Couple questions:

How do you go for brake bias?

What mu value do the Hawks have?

I am working on a brake upgrade, but my present rims won't clear anything worthwhile. This is probably why I get annoyed at having to throw good money at a substandard set up. Something which, in turn further delays the proper fix I need.

[Angus Smart]

Go the f50's!

back on the topic about the rotor size from a while back..

i'm looking at 330-331 0r 332. somewhere around that mark

if there is a rotor in that size looks to be dixcel again tho and i looked into them.. what else do you want me to measure?

[Sydneykid]

Couple questions:

How do you go for brake bias?

What mu value do the Hawks have?

I am working on a brake upgrade, but my present rims won't clear anything worthwhile. This is probably why I get annoyed at having to throw good money at a substandard set up. Something which, in turn further delays the proper fix I need.

On the race cars we run twin master cylinders obviously, with Tilton adjusters and Hawk HT10's all round. My R32GTST still has the OE booster and master cylinder so I run different pad compounds front to rear. Currently I have HT10's in the front and HTC60's in the rear as the front brakes have been upgraded as per above, but the rear rotors are the standard size 4000 series. I have used a Tilton pressure limiter for the rears in the past, but the split compound has made that prety much redundant. Matt's R33GTST still has the OE booster and master cylinder and as it is a daily driver we run Hawk HP Plus in it. The front rotors are 324 mm 5000 series and the rear rotors are the standard size 4000 series. It has no ABS and is heavily front brake biased, so you have to be careful not to lock the fronts.

The R32GTST has ducting from the lower vents on its R32GTR front bumper, one to each rotor. That is there permanently for hillclimbs lap dashes etc. For track days, where the session are longer, the rear has the Gibson R32GTR like ducting from under the rear seat floor to the rear rotors.

There is a tendancy away from publishing CoF's because it can be misleading. People were tricked into buying pads simply on their one temperature point CoF, the higher the better. Which is pretty silly when you think about it, what about the other temperatures? You don't drive along with the pads constantly at, say, 650 degrees C, the temperature rises and falls constantly. What's the good of a pad that has a CoF of 6 at 650 degrees and 3 at 500 degrees? You would never be able to use it effectively. That's where the ratings of initial torque, fade resistence, release, modulation, pad wear and rotor wear are more useful.

Cheers

Gary

[Scooby]

Buy some cheap F40/50s as i have all the drawings now to mount them on 324, 343, and 355mm rotors. I am now running my F40s on 324mm after having an accident with a flight of stairs and my 343mm rotors

Roy what type of 355s? I'm about to get some brackets made to mount GT-P 355mm 5000s onto a 32 GTR with F50s. They have about 2mm less offset than the GTR disc and I'll order them blank so I can have them redrilled. Happy to come to an arrangement if the specs you have come close.

Cheers

[Roy]

Roy what type of 355s? I'm about to get some brackets made to mount GT-P 355mm 5000s onto a 32 GTR with F50s. They have about 2mm less offset than the GTR disc and I'll order them blank so I can have them redrilled. Happy to come to an arrangement if the specs you have come close.

Cheers

So you are buying DBA 5000 series 355mm rotors off the Ford but with undrilled alloy hats? Which way is the offset different? The brackets would be relatively easy to make up...the drawings i have are all centred around Brembo hats or the CSC (Now B Max) rotors

If you already have a place sorted then stick with them. That way you have a guarantee its all A1, rather then me working from CAD models.

What are the DBA 355 5000s worth out of interest?

[Scooby]

So you are buying DBA 5000 series 355mm rotors off the Ford but with undrilled alloy hats? Which way is the offset different? The brackets would be relatively easy to make up...the drawings i have are all centred around Brembo hats or the CSC (Now B Max) rotors

If you already have a place sorted then stick with them. That way you have a guarantee its all A1, rather then me working from CAD models.

What are the DBA 355 5000s worth out of interest?

Yes, 355 mm DBA 5000s with undrilled hats.

Discs I considered:

GTR height 53.75mm centre 68 pcd 114.3

GTP height 50.5 (355 diam ) centre 71.8 pcd 114.3 larger studs

Chrysler SRT 8 height 53.5 mm (360 diam ) centre 72 (32mm thickness, DBA cattledog min 31.8mm. misprint?) centre 72 pcd 115 mm

Viper SRT 10 height 59.6 (355 diam ) centre 73.6

C6 Corvette height 45.5 (355 diam) centre 70.7

I assessed the best most commonly available disc for the application is the GTP. The SRT 8 was another consideration due to the similar offset. However, I reckoned DBA would stop making discs for SRTs before the GTP and they are also a slightly different size, whereas I'm likely to be able to adapt another 355mm size disc to the GTP hat as I suspect all 355x32 5000 discs are the same.

There is the option of making spacers for the GTP studs and centre hole rather than redrilling but I'd prefer to just get the hats redrilled for $90 / side rather than stuff about with 'bits' and invariably lose one on the garage floor at some stage.

GTP 5000 hat and rotor is $525 / side if you don't go to Repco.

Cheers

[Roy]

Another option that i could end up doing now that i killed my 343mm rotors is Merc ML430mm rotors, They are either 340mm or 343mm and 32mm thick...if they can stop a fark off heavy AWD recreational Merc then they can stop my car from speed. And cheap as chips 1 pce rotors (which will work well with R33 GTS25t or R32 GTR Calipers )

[Scooby]

I did look at Merc rotors,

ML 270 / 400 TD and 430 V8 are 345 x 32, 51mm high and centre hole 67mm but again they're not 355.

I decided it was either upgrade to 355mm min or nothing as I already have 324mm Brembos, as well as the previously mentioned popularity advantage of the 355mm rotor.

I agree you can get them very cheaply, particularly from o/s. I'm amazed at the low price of replacement OEM euro stuff but beware of their origins and how they might perform if you track them.

Edited February 14, 2008 by Scooby

[Sydneykid]

Be carefull matching DBA 5000 Series hats and rotors, they don't all run the same rotor PCD or stud pattern. Some common ones are 7 bolt, some 11 and I have even seen 14 bolt.

Another warning, like wheels, the hub centre is the best locator for the hat. Using wheel studs alone for centricity is not something I would recommend.

Cheers

Gary

[djr81]

Can you take it off and take a few pics. ANy tint of blue off the area that the pad comes in contact with, on either the inner or outer face of the rotor. Are you running any sort of brake ducting? What pads are you running and also how old etc are they.

Here you go.

Standard 4000 series crack. Started from the return slot & propogated inwards. Full width & depth of the rotor. I measured the rotor wear at 0.1mm, so like new.

Only was a rear so it doesn't work for a living. It's just bad design.

Photos are not working presently. I will post it later.

Edited February 15, 2008 by djr81

[R338OY]

OK, i'm staying clear of DBA now.

[Scooby]

Be carefull matching DBA 5000 Series hats and rotors, they don't all run the same rotor PCD or stud pattern. Some common ones are 7 bolt, some 11 and I have even seen 14 bolt.

Another warning, like wheels, the hub centre is the best locator for the hat. Using wheel studs alone for centricity is not something I would recommend.

Cheers

Gary

Hi Gary

Thanks for the tip, it's not something I'd looked into as I'd made my mind up about the GTP ones. I was never going to use the hub locator or studs in a mismatched situation, and either use spacers as a short term option or a blank hat correctly drilled for both, which is my preference.

However I am keen to see if I can find some used but sound GTP rotors as I'd like to use spacers initially to see if I'm sold on the 355 disc conversion rather than shell out for new 5000s striaght away.

Cheers