Dba 4000 T3 Rotors - Catastrophic Failure At Track

[dan.1337]

I've read of cracking issues with these rotors, but has anyone else had the rotor completely separate from the hub with their DBA4000 T3 rotors?

I was punting it down the main straight at Winton on the weekend, put my foot on the brakes at around 180kmh, then bang! Straight off into the grass because I wasn't able to stop.

[niZmO_Man]

Horrey sheet.

[GTSBoy]

You need to get that rotor in front of a DBA failure/claims engineer ASAP.

[Hadouken]

holy shit! thats scary

[Duncan]

That is an impressive way to end a rotor.

I assume there was not horrible thrumming immediately before it happened? I note DBA advertise their 4000 series as "Road and Race" so I am sure they won't try and avoid responsibility if it was their issue.

[dan.1337]

  On 14/09/2015 at 5:43 AM, GTSBoy said:

You need to get that rotor in front of a DBA failure/claims engineer ASAP.

I was planning on turning it into a clock since the centre has been pretty nicely sheared away, but getting it front of DBA may be a better idea.

  On 14/09/2015 at 5:59 AM, Duncan said:

That is an impressive way to end a rotor.

I assume there was not horrible thrumming immediately before it happened? I note DBA advertise their 4000 series as "Road and Race" so I am sure they won't try and avoid responsibility if it was their issue.

There was no noticeable noise as I was coming hot down the straight, put my foot down and it pretty much got destroyed straight away. It happened after doing two warm up laps where I tried to avoid using the brakes too much so I could keep the brakes warm, but not hot.

[endless]

f**king wow! Well done not crashing

[Trex]

^ This. lucky you didn't spin.

How old are they? What thickness were they if they have been machined?

[V28VX37]

Holy crap, very lucky indeed not to crash bad!!

I'm running the same discs, makes me nervous, very keen to hear more:

• Age of discs
• # of track days
• Disc thickness
• Pad and fluid type
• Wheel type
• Any brake cooling
• Any early signs of potential failure

Interested in hearing what DBA have to say, too!

[Trex]

DBA Lees.

haha

[GTRPSI]

  On 14/09/2015 at 5:43 AM, GTSBoy said:

You need to get that rotor in front of a DBA failure/claims engineer ASAP.

Unfortunately DBA (and RDA) wont cover them, only warrantied under normal street use, the moment you hit track any warranty you had is out the window.

Quite a common thing to happen when shocked into heat, they crack from the rapid heat expansion, cast iron needs to be warmed up gradually to avoid cracking it.

You can actually see its riddled with cracks all the way around from rapid heating......

Easily identified by the radiating lines outwards from the hub center all the way around.

When hitting a track, you should use the first lap to build heat into the brakes, that way they are reasonably warm when you start your flying lap, then the differences in temp change are far less and the rotor expands less from running hard cold and running hard hot.

Take a off the shelf rotor from stone cold and hit the straight with a high enough temp rating pad, slam on the brakes with everything you have and bingo, great chance of getting a cracked rotor.

Edited September 14, 2015 by GTRPSI

[niZmO_Man]

He said he did warm up laps...

[GTSBoy]

  On 14/09/2015 at 10:30 AM, GTRPSI said:

Unfortunately DBA (and RDA) wont cover them, only warrantied under normal street use, the moment you hit track any warranty you had is out the window.

I wasn't actually suggesting that he make a claim. My intention was that DBA could look at the failure and see if there was anything they could learn from it. Sometimes there are hidden manufacturing faults (basically just casting defects) that will survive years of use on a road car that will break on track usage, exactly as you say. They never learn from the ones that don't break on the street, but they should be given every opportunity to see the ones that do.

An old example is the habit of Holden 6s to break timing gears and occasionally snap the front end off the camshaft. I reckon that Holden learnt something about castings because it eventually stopped happening.

[dan.1337]

  On 14/09/2015 at 9:58 AM, V28VX37 said:

Holy crap, very lucky indeed not to crash bad!!

I'm running the same discs, makes me nervous, very keen to hear more:

• Age of discs
• # of track days
• Disc thickness
• Pad and fluid type
• Wheel type
• Any brake cooling
• Any early signs of potential failure

Interested in hearing what DBA have to say, too!

Rotors were around 2 years old and have done about 6 track days and around 2000km of street driving. The rotors actually have very minimal wear, but started to get hairline cracks which is pretty common for tracked rotors.

Using Project Mu HC+ pads with ATE Super Blue fluid and semi slicks.

  On 14/09/2015 at 10:30 AM, GTRPSI said:

Unfortunately DBA (and RDA) wont cover them, only warrantied under normal street use, the moment you hit track any warranty you had is out the window.

Quite a common thing to happen when shocked into heat, they crack from the rapid heat expansion, cast iron needs to be warmed up gradually to avoid cracking it.

You can actually see its riddled with cracks all the way around from rapid heating......

Easily identified by the radiating lines outwards from the hub center all the way around.

When hitting a track, you should use the first lap to build heat into the brakes, that way they are reasonably warm when you start your flying lap, then the differences in temp change are far less and the rotor expands less from running hard cold and running hard hot.

Take a off the shelf rotor from stone cold and hit the straight with a high enough temp rating pad, slam on the brakes with everything you have and bingo, great chance of getting a cracked rotor.

I did two warm up laps at around 60% of normal pace, then 80%, so they would have been pretty warm by the time I hit the brakes.

Not really confident that DBA will get back to me with any sort of resolution in my favour, but I've written the rotors off and will go for something else in the future. The 4000 series are too expensive to run for such a short time. I'd rather go for a cheaper RDA and swap them out more often after they start to get hairline cracks.

[GTRPSI]

  On 14/09/2015 at 11:28 AM, GTSBoy said:

I wasn't actually suggesting that he make a claim. My intention was that DBA could look at the failure and see if there was anything they could learn from it. Sometimes there are hidden manufacturing faults (basically just casting defects) that will survive years of use on a road car that will break on track usage, exactly as you say. They never learn from the ones that don't break on the street, but they should be given every opportunity to see the ones that do.

An old example is the habit of Holden 6s to break timing gears and occasionally snap the front end off the camshaft. I reckon that Holden learnt something about castings because it eventually stopped happening.

Unfortunately most of their rotors are cast in China to keep cost down through a number of plants, part numbers come from different casters, not just 1 plant.

They warranty them for street use, knowing they will work safely within those parameters, they have been proven to be well made in that environment.

If customers want to take things to the next level DBA have a range of proper 2 piece track rotors designed to take that abuse, now if they cracked, id suggest taking them in for research and development and to see what they would say and if they could improve the product.

I doubt they will look to improve whats currently a price point product, that currently works well for what its designed to take, ATM the brake rotor game is extremely competitive in pricing, both RDA and DBA both have a good performance street range which works well while holding prices down to keep customers happy.

Just like you wouldn't build a highly strung engine with stock rod bolts and then take the broken rod bolts to the engine manufacturer to show them what happens when you push a part beyond its recommended usage, im sure the engineer looking at it could have told you it would have happened before you did it.

[GTRPSI]

  On 14/09/2015 at 11:34 AM, dan.1337 said:

Rotors were around 2 years old and have done about 6 track days and around 2000km of street driving. The rotors actually have very minimal wear, but started to get hairline cracks which is pretty common for tracked rotors.

Using Project Mu HC+ pads with ATE Super Blue fluid and semi slicks.

I did two warm up laps at around 60% of normal pace, then 80%, so they would have been pretty warm by the time I hit the brakes.

Not really confident that DBA will get back to me with any sort of resolution in my favour, but I've written the rotors off and will go for something else in the future. The 4000 series are too expensive to run for such a short time. I'd rather go for a cheaper RDA and swap them out more often after they start to get hairline cracks.

Those earlier hair line cracks you had are usually just surface deep.

We see a lot of track day rotors like this, quite often a fine marbling of the braking surface where the cracks are very shallow, a simple light skim will remove them.

However, not machining the rotors (you mention 6 track days) "may" (something ive always suspected in the early days and after watching had seen) lead to these cracks growing, or lead to a larger full crack developing due to the weakness from the earlier cracks.

Just like how once a part is cracked, the crack will continue to grow along the current one.

Most rotors with the surface marbling that ive watched, progressively got worse with the cracks growing in width and depth the longer they were used, the rotor heating and cooling (expanding and contracting) aggravating the issue.

Its one of the reasons i now tell people doing track days to keep an eye on 1 piece rotors for any cracks developing, if they see a surface craze finish to simply lightly machine the rotors to remove it before driving on them.

You can never be too safe, then again, using the right rotor in the first place may have been more appropriate however the costs of the good stuff is pretty much out of range of the average person doing the odd track day.

You mentioned you used HC pads, what is the temp rating of the pads? I know the HC800 are rated to 800 degrees.

I piece rotors shouldn't be subjected to over 600 reliably, once you go over that your looking for issues.

Edited September 14, 2015 by GTRPSI

[Trex]

  On 14/09/2015 at 1:55 PM, GTRPSI said:

Unfortunately most of their rotors are cast in China to keep cost down through a number of plants, part numbers come from different casters, not just 1 plant.

They warranty them for street use, knowing they will work safely within those parameters, they have been proven to be well made in that environment.

If customers want to take things to the next level DBA have a range of proper 2 piece track rotors designed to take that abuse, now if they cracked, id suggest taking them in for research and development and to see what they would say and if they could improve the product.

I doubt they will look to improve whats currently a price point product, that currently works well for what its designed to take, ATM the brake rotor game is extremely competitive in pricing, both RDA and DBA both have a good performance street range which works well while holding prices down to keep customers happy.

Just like you wouldn't build a highly strung engine with stock rod bolts and then take the broken rod bolts to the engine manufacturer to show them what happens when you push a part beyond its recommended usage, im sure the engineer looking at it could have told you it would have happened before you did it.

That's rediculous. 4000 t3 are sold as road AND TRACK. So to say they were only made for the road and they work well in that environment is bullshit. Why do they market them for the track if they aren't up to the task?

Your defensive posts have so many flaws. How hard would it have been to say 'sorry about your misfortune send the rotor to myself or dba and we will check the rotor for flaws etc. thankfully you weren't seriously injured'

[Daleo]

  On 14/09/2015 at 1:55 PM, GTRPSI said:

Unfortunately most of their rotors are cast in China to keep cost down through a number of plants, part numbers come from different casters, not just 1 plant.

They warranty them for street use, knowing they will work safely within those parameters, they have been proven to be well made in that environment.

If customers want to take things to the next level DBA have a range of proper 2 piece track rotors designed to take that abuse, now if they cracked, id suggest taking them in for research and development and to see what they would say and if they could improve the product.

I doubt they will look to improve whats currently a price point product, that currently works well for what its designed to take, ATM the brake rotor game is extremely competitive in pricing, both RDA and DBA both have a good performance street range which works well while holding prices down to keep customers happy.

Just like you wouldn't build a highly strung engine with stock rod bolts and then take the broken rod bolts to the engine manufacturer to show them what happens when you push a part beyond its recommended usage, im sure the engineer looking at it could have told you it would have happened before you did it.

To the two points I've highlighted in red;

I did a factory tour last year with Members of SAU NSW for one of our most excellent Tech Arvo's organised by the Club Execs.

1; According to DBA; ALL 4000 Series and 5000 Series are cast in a proprietary grade of cast iron in a foundry based in Sydney. This is to guarantee the quality & consistency of their flagship product.

2; In the standard R33 GTS-t rotor size; there is no DBA 2 piece rotor available, so you are left with the 1 piece 4000 series T3 slotted rotor OP has quite reasonably decided to use for trackwork on what I'd assume is a modified STREET CAR, not a dedicated track car.

6 track days and 2000km of street use doesn't "seem" like a great deal of time, and the nature of the failure isn't something that you'd expect; and even DBA suggest that an amount of radial surface cracking in tracked rotors is perfectly normal, and to be expected (as you have also pointed out).

I'd definitely be approaching DBA, and asking for their guidance, and possible ways to move forward; they are (in my experience) excellent to deal with, and are very understanding of enthusiasts who use their product as it was designed.

Simply telling people that they have misused the product and that they should suck eggs is hardly helpful.

Cheers, Dale.

[_Wing_]

:blink2: :blink2: :blink2:

[djr81]

They are marketed as road and track but warranted only for road.

The best answer to this is either Dixcel or Project Mu.