Drilled / Grooved Front Discs or Not?

[M80]

I'm replacing the front discs on the Viano.
It isn't a sports car and I don't try and drive it like one.
On occasion there can be a fair weight in the back.

But I do like brakes to be effective, cos imo that makes the driving easier.
Do drilled and grooved discs make for easier braking, in the wet is when these are supposedly advantageous?
Or are they boy racer placebo?

I'm fitting ECB Greens, mainly for the reduced dust. Reds aren't available.

 

[brandwooddixon]

I often think that the biggest difference is pad selection and the way in which you bed new discs in.

Drilled discs can cause issues if you tend to brake gently as the holes rust up and you get high spots due to differential wear rates.
From my boy racer days I remember a noticeable difference when fitting grooved discs, but I suspect that some of that may come from bedding the pads in more quickly.

The fact that race cars don't tend to use grooved nor drilled discs should say it all, although larger diameter discs will give increased braking power, whilst thicker discs, with internal venting can distribute and shed heat more effectively.

I find that putting new discs and pads through a number of heat cycles works best. Find a quiet stretch of road with good visibility then :
1. accelerate to 30 mph then brake moderately down to 10 mph. Repeat 6 times.
2. accelerate to 60 mph then brake firmly down to 10mph. Repeat 6 times. This heats the discs and pads burning off volatiles
3. drive without stopping and with only gentle braking, when necessary, for 5 - 10 minutes to allow the brakes to cool down.

Stage 1 deposits pad material on the disc.
Stage 2 burns off volatiles in the pads (out gassing) and starts the heat treatment of the disc. You should be able to smell the brakes at this stage.
Stage 3 is important as it allows the disc to cool down evenly, reducing the possibility of warping or leaving an uneven transfer of pad material on the disc.

I might repeat the above for half the number of cycles. If I need to stop, due to traffic, part way through a stage I repeat it from scratch.

I then ensure that once in a while I warm the brakes up again and then brake hard to an almost stop. This seems to keep the brake surfaces conditioned.

Typically brake fade is due to outgassing from the pads, reducing the level of friction between pad and disc - cross drilling and grooves on the disc allow the gas to escape.

 

[DSK]

I’m not going to say anything about your pad choice as some folks love ebc some don’t and my one and only experience years ago with red was unpleasant.

ATE do powerdisc and Brembo do a powemax. Both with grooves and I’ve alway them with Ferodo DS2500 and Carbotech XP8. Perfect performance and even with the standard discs from both. I doubt these would be available on the Viano but you check AUTODOC.

What about ATE ceramic pads for low dust? They are available for most makes and models from AUTODOC also.


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