DBA Rotor Comparison

[Luke]

Is this for an NB8A or NB8B.
I still have my standard factory rotors in the rear of my SE, and have not had a probem with them at all for track use.
I'm on my 3rd set of fronts though. I had the the factory original, 6x6 Wiper Slot 4000, and now the T3 4000 at the front.
To be honest I havn't noticed an increase in braking capacity with either over the standard rotors. But where the big difference is the pads stay much more uniform. With the standard rotors, chunks broke off the pads every now and then, and I guess thats because of trapped gasses. This then caused scoring of the discs.

I find the T3 4000's much noisier than the old 6x6 design and it causes more vibrations through the pedal. Exactly opposite of what DBA says.

I just go with the 4000 Series for piece of mind since they are supposively designed for track conditions.

Pretty sure they don't do the 5000's with aluminium hats in standard MX-5 sizes, so no point looking at them.

Also noticed they don't have plain 4000's any more. Looks like they have been remarketed as HD Direct.
And standard rotors are no longer available with Kangaroo Paw? Good thing I bought my rotors for the Falcon when I did then.

[Aussie Stig]

Would second not being concerned with the rear rotors so much. As long as the fronts are top quality.

What's the price and I guess you did not you get them locally?

[marcusus]

I've ended up going the 4000 series T3 for the fronts, and the T2's for the rear. Price wise was great from Race Brakes Sydney. They were able to do the 4000 series T3 fronts for $160 each, and the T2 rears for $115. Shipping to Perth was $42, so all up it was $592. The cheapest I could find locally was $730, and that didn't even include shipping! Stupid expensive State that it is...

Luke: It's an NB8A. The last time I took the car in for a service, they reckoned the discs needed machining (and they sure do!), and that they may only have one more machining left in them. So I figured instead of paying however much for machining, I just get new rotors straight off the bat.

So, we'll have to wait for them to arrive, and we'll see how they go. I'm sure that the DBA's in conjunction with the Hawk HP+ pads I'm going to put on will make the car pull up much much better than the factory rotors and the EBC greens I have on at the moment.

[NitroDann]

The rotors themselves wont make an ounce of difference on the street and probably wont make any difference 95% of the time on the track.

Dann

[Regie]

Hey Marcus

a brake bleed with fresh fluid will make the most amount of difference

throwing on slotted rotors made stuff all on the track and street... but it does look cool

[Aussie Stig]

When you have it done give us the real life assessment. Pretty sure it's going to work out really well.

[NitroDann]

If you are disputing what myself and regie have said. Do the math, its the same friction coefficient and reduced surface area. How can It improve stopping before brake fade?

Dann

[Regie]

When you have it done give us the real life assessment. Pretty sure it's going to work out really well.

im talking from real life assessment.... I did exactly what Marcus is doing

all i said was brake fluid change/renewal made the most difference for me....just spreading my knowledge/findings.

others may feel a difference elsewhere

now i own a NC, i changed the fluid at 25,000kms and man what a difference it made...

Brake fluid should be changed at least once a year at most....that sh1t is hydroscopic as hell

[Aussie Stig]

There have been thousands and thousands drilled/slotted discs sold over the years and still they sell and at a hefty premium.



So what is it, everybody being conned or is our car different? I respect the combined wisdom of the forum.

I am severely tempted but not for the factor. Maybe they give extra 'bite' to the pads under pressure. Flogged if I know.

Slotted rotors were the first recommendation for the MK1 gti - a car with some of the worst brakes I have known....one of the best engines though.

[project.r.racing]

The pad materials control bite, not the rotors. Rotors only help with gasses being trapped or overheating of pads which limit said bite at those hotter temps.

In street car in street use, the brake components might hit 300C if lucky (on a really hot day). Well under the specs even cheap $50 pads can handle. But a street car in track use, they will easily top 450C, and will get to 600C if you push them hard enough. This is where you'll see the rotors come into play by reducing those gasses and pad temps.

I've seen some advertized motorsport pads rated at maximum friction co-efficient at 550C. Can everybody say brake fade by the 5th lap? lol

I'm currently using TRWs which are rated as 0.54 @ 650C. Lots of pad lift, most of the slots have been rubbed off the rotors.

Anyway, I agree with the statement above about not noticing the difference in rotors on the street. You will notice more bite, but that'll be because you just replaced the pads with good pads and you bled the fluid lines.

[Aussie Stig]

I love all the technical and real life responses in this forum.

The consensus remains, slots and drilling for the street is more for show than go - or in this case stop! As you say other factors probably would give more satisfaction, like changing the fluid.

On that note, I am sure my brake fluid is more than 4 years old but when my mech. stuck his flashy digital tester in the fluid he said it was 100%. Brake fluid doesn't wear out, does it and if it has no moisture then it does not need to be changed?

[marcusus]

A fluid change will also be part of the process, and no doub that'll make a difference. Same with the pads, as that'll make a difference too. In my opinion, I think the rotors will do the least for my braking, followed by the pads, followed by a fluid change. As mentioned, the reason I need new rotors is that they're running thin, so instead of machining or getting stock rotors, I figured I'd get rotor upgrades.

If you read through someone like Hellmun's garage thread, I don't think he's mentioned that the rotors made a difference to the quality of his braking, but certaintly made a difference to the longevity of use ie upgraded rotors last longer than regular rotors when used aggressively on the track. Sounds to me like they do make some difference, although whether that difference is in increased stopping power, I'm not sure.

Either way, I'll definitely post up what I feel once I've changed everything. Of course the problem is that three variables with have been changed (fluid, pads and rotors ) so it will be hard to differentiate which one caused what result. In the end, so long as it stops better than it currently does, I'm sure I'll be happy.

[Guran]

Brake fluid $10 = most noticeable benefit
Brake pads ~$200 = next best benefit
Slotted rotors $600 = least noticeable benefit

A bit of a trend there!

I'm puzzled why you'd be willing to spend near $600 on a set of rotors that will do the same job for you as <$300 regular rotors. Save your money or spend it elsewhere. Also if you've still got enough thickness in the old ones, it seems wasteful to chuck them in the recycle bin when a machine should only cost less than $100 for all four.

[Lokiel]

:
The consensus remains, slots and drilling for the street is more for show than go - or in this case stop!
:

DD in the wet, I'd prefer slotted rotors, they disperse water too so you have a better chance of "emergency stopping".

[Hjt]

Slotted rotors don't heat sink as much as a solid peice. Difference is pathetic though.

Good fluid +1