Jump to content
SAU Community

Cross Drilled Verses Slotted

Global_Warmer
 Share

Recommended Posts

Global_Warmer Proficient

Global_Warmer

Posted
Posted

I am after some new brake rotors for my 260RS Stagea. I want to do track days but I am worried about cross drilled brakes being "weaker" than slotted rotors and therefore warping under extreme heat conditions.

Am I being to worried and under informed here?

I can only get cross drilled (apparently) for the front so will have to run slotted on the rears. Will this be an issue?

Also can someone clear up... does this car have an R33 or R34 drivetrain.

Thanks!

Link to comment
https://www.sau.com.au/forums/topic/340629-cross-drilled-verses-slotted/
Share on other sites
GTR-N1 Grand Master

GTR-N1

Posted
Posted
I can only get cross drilled (apparently) for the front so will have to run slotted on the rears. Will this be an issue?

Thanks!

How come you can only get cross drilled for the front?

There's no problem tho' to run cross drilled at the front and slots at the rear.

Cons:

Under heat, cross drilled can form blue heat patches and then a bit of cracking.

Even slots that go right up to the edge of the rotor can crack too. DBA found this out soon enough

Pros:

Slots that stay within the edges are desirable whether they be straight or fish-hook

Dimpled rotors are fine (as in RDA)

Curved vanes within the ventilation space are desirable

MrStabby Grand Master

MrStabby

Posted
Posted

The cross drilled that came on my car cracked at the track, as did DBA4000s with the retarded slot design....

Very surprised you cant get slotted for the fronts - I would have guessed that your RS would have had GTR brakes or similar. The 33 and 34 GTRs had the same sized rotors. Do you have brembo calipers?

MrStabby Grand Master

MrStabby

Posted
Posted
Even slots that go right up to the edge of the rotor can crack too. DBA found this out soon enough

My guess is that its more that the slot is almost perpendicular to the edge, rather that the fact that it runs right to the edge (but agreed that is also undesirable)

The RDA dimpled/slotted/gold ones run the slot all the way to the edge, but the slot is the conventional 45 degrees or so to the edge. They've been ok for me, unlike the DBA4000s.

Global_Warmer Proficient

Global_Warmer

Posted
  • Author
Posted
The cross drilled that came on my car cracked at the track, as did DBA4000s with the retarded slot design....

Very surprised you cant get slotted for the fronts - I would have guessed that your RS would have had GTR brakes or similar. The 33 and 34 GTRs had the same sized rotors. Do you have brembo calipers?

You can get slotted alround. But can not get cross drilled for the rears, only the fronts.

the vehicle has Brembo brakes alround.

R32.GTR Collaborator

R32.GTR

Posted
Posted
My guess is that its more that the slot is almost perpendicular to the edge, rather that the fact that it runs right to the edge (but agreed that is also undesirable)

The RDA dimpled/slotted/gold ones run the slot all the way to the edge, but the slot is the conventional 45 degrees or so to the edge. They've been ok for me, unlike the DBA4000s.

shit.. just bought slotted DBA4000s

are they really that bad?

GTR-N1 Grand Master

GTR-N1

Posted
Posted

^^^ If the ends of the slots are away from the perimeter of the rotor, it's all ok.

If your slots do meet the edge of the rotor at something like a 45 degree angle, you just need to watch them.

But there have been some batches of DBA 4000s with 5-10mm length slots meeting with the edge and perpendicular to the edge that have been notorious for cracking (via high heat > expansion > contraction).

When I cut glass (in leadlighting), I must start the cut right from the edge/perimeter > the glass is much more easy to break.

Another example is that medicinal tablets are meant to be 'scored' right up to the edges, to facilitate breaking cleanly - otherwise they're hard to snap.

Therefore, heat-cracking on cross drilled rotors starts at the extreme edge of the hole - which is the weakest point.

MrStabby Grand Master

MrStabby

Posted
Posted
shit.. just bought slotted DBA4000s

are they really that bad?

They were pretty bad - Here is the thread. The bottom of the third page shows my ones, they don't have the slot all the way to the edge (it stops just short). I dont know if they've updated the design since then. If you're not tracking it it will be fine.

  • 2 weeks later...

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • Duncan
      Duncan's V37.......race car?

      By Duncan · Posted

      So, before putting them in I need to understand the stock ride height. This is how I measured it: First, check the diameter of the wheel's centre cap, it was 52mm. Then put a piece of masking tape approximately across the centre and measure 27mm (half) from at least 3 sides to get a reasonable idea of the centre of the wheel cap. Mark that with a horizontal line as one measuring point. Then, directly above the wheel on the guard, put another piece of masking tape in approximately the centre. Use a string line to find out the point on the guard above the centre of the wheel cap and mark that. Then it is simple, just a tape measure to check the distance from centre of the wheel to the centre of the guard. Final results where  LF: 381mm RF: 379mm LR: 401mm RR: 400mm Pretty even considering they are 120,000klm old factory springs, lets call that 380 front and 400 rear.
    • Duncan
      Duncan's V37.......race car?

      By Duncan · Posted

      So....knowing that I have a problem with power steering temps on track and another Wakefield day booked in next Friday, I've done the obvious thing They are very reasonably priced at $1650, considering they are a big monotube shock, double height adjustable (don't have to change pre-load to change ride height), one way adjustable damping and standard sized and customisable springs if you want something other than what comes with them. They come with 9kg/mm front and 4.5kg/mm front and I went with that as a starting point because I'll add adjustable sway bars too https://justjap.com/products/bc-racing-coilover-kit-ds-ds-infiniti-q50-v37-14-current#description Unfortunately they didn't come with rear strut tops so I've re-used the factory ones which was a bit of a pain. Also, the adjuster for the rear shock will be an absolute nightmare to get at, and while there are extensions in the kit I can't see any way you can actually attach or use them
    • Duncan
      One Headlight isn't working - Driver Side Fuse Keeps blowing

      By Duncan · Posted

      I also had 2 bulbs blow at once, years ago in the stagea. made for a fun drive home. The issue was the voltage regulator had failed in the alternator and it was giving 15+ volts. Really, I was lucky all that was fried were the headlight bulbs. So, I'd suggest you check the voltage across your battery terminals with the car running and warmed up. Yes, you will need a multimeter to do so, sorry.
    • Duncan
      R32 GTS (RB20DE) Injectors Replacement

      By Duncan · Posted

      Good work to think to check that, and thanks for coming back to post up the outcome.
    • Duncan
      98 R34GTT 4k engine stumble

      By Duncan · Posted

      Given it happened suddenly, and when you come on boost, I'd check all your inlet - hose clamps in place and no split rubber or silicone hoses. Even the hard to get to ones near the intercooler. It's possible air that went past the air flow meter is being dumped out a big hole.
×
×
  • Create New...