Drilled rotors

[hillbillydmc]

Hey,
Anyone tried these from DAP?

[Nicholas R]

Hey,
Anyone tried these from DAP?

Are those John Herveys? If so I believe they're just stock rotors that he has holes drilled and chamfered in. Cliff Schmucker had a set on a shelf that I've looked at but we never put them in a car. They seemed pretty well done; plated after drilling.

Still the true test is going to be running them and seeing if any cracks propagate from the holes when they cycle thermally. Typical "drilled rotors" are actually cast with the holes in them so there is no residual stress in the part from a drilling process. I am not sure if John performs a stress relief on the discs after machining but I had to guess, I'd probably say no.

[hillbillydmc]

Are those John Herveys? If so I believe they're just stock rotors that he has holes drilled and chamfered in. Cliff Schmucker had a set on a shelf that I've looked at but we never put them in a car. They seemed pretty well done; plated after drilling.

Still the true test is going to be running them and seeing if any cracks propagate from the holes when they cycle thermally. Typical "drilled rotors" are actually cast with the holes in them so there is no residual stress in the part from a drilling process. I am not sure if John performs a stress relief on the discs after machining but I had to guess, I'd probably say no.

Hey,

Yes those are John Herveys. I am thinking about trying a set of them with EBC red stuff pads on all four corners. If I do I will keep the group posted on there performance.

Thanks for the info!:smile:

[DCUK Martin]

Don't combine drilled discs with redstuff pads.

Drilling brake discs was originally conceived as a measure to help with overheating brake pads. As they start to burn, the gases produces a "cushion" between the friction material and the surface of the disc, affecting braking. The drilled holes give somewhere for the gases to go, keeping the friction material functional for longer. They also improve cooling.

...but it was only ever treating the symptoms and not the disease. If the pads are already overheating, you have bigger fish to fry.

Redstuff pads are deisgned to run at higher temperatures and won't overheat on stock discs this side of track use (the brake fluid is the limitation you'll hit first). They rely on the discs heating up reach optimum performance. Using drilled discs will make this effect worse.

[Nicholas R]

I didn't realize that they were also slotted. That would help keep your pad wear more consistent and even.

Still, it could be just me, but that seems like a lot of holes. Looking at other drilled rotors, it just seems like the ratio of hole to disk surface area is a lot higher.

Also the website says they run 250 degrees cooler. That seems pretty lofty to me and very subjective.

http://www.specialtauto.com/delorean-parts/images/delorean-crossed-drilled-ro.jpg

[hillbillydmc]

Don't combine drilled discs with redstuff pads.

Drilling brake discs was originally conceived as a measure to help with overheating brake pads. As they start to burn, the gases produces a "cushion" between the friction material and the surface of the disc, affecting braking. The drilled holes give somewhere for the gases to go, keeping the friction material functional for longer. They also improve cooling.

...but it was only ever treating the symptoms and not the disease. If the pads are already overheating, you have bigger fish to fry.

Redstuff pads are deisgned to run at higher temperatures and won't overheat on stock discs this side of track use (the brake fluid is the limitation you'll hit first). They rely on the discs heating up reach optimum performance. Using drilled discs will make this effect worse.

Thanks for the info! LOL:biggrin:

[hillbillydmc]

I didn't realize that they were also slotted. That would help keep your pad wear more consistent and even.

Still, it could be just me, but that seems like a lot of holes. Looking at other drilled rotors, it just seems like the ratio of hole to disk surface area is a lot higher.

Also the website says they run 250 degrees cooler. That seems pretty lofty to me and very subjective.

http://www.specialtauto.com/delorean-parts/images/delorean-crossed-drilled-ro.jpg

Hey,

Yea, 250 seems a little out there, but I believe they would be a good upgrade for only $20.00 more each over the stock rotors.

Thanks!

[D Knight]

They will also be much more noisier. I'd like to see how he got the 250 degree cooler info


-D Knight-

[hillbillydmc]

Don't combine drilled discs with redstuff pads.

Drilling brake discs was originally conceived as a measure to help with overheating brake pads. As they start to burn, the gases produces a "cushion" between the friction material and the surface of the disc, affecting braking. The drilled holes give somewhere for the gases to go, keeping the friction material functional for longer. They also improve cooling.

...but it was only ever treating the symptoms and not the disease. If the pads are already overheating, you have bigger fish to fry.

Redstuff pads are deisgned to run at higher temperatures and won't overheat on stock discs this side of track use (the brake fluid is the limitation you'll hit first). They rely on the discs heating up reach optimum performance. Using drilled discs will make this effect worse.

Hey,
EBC said it was fine to combine drilled discs with there redstuff pads.

[hillbillydmc]

They will also be much more noisier. I'd like to see how he got the 250 degree cooler info


-D Knight-

Hey,
Do you know these will be noisier, heard them on your D, or do you think they will be noisier:confused0:.

Thanks for the info:smile:

[Nicholas R]

Hey,
Do you know these will be noisier, heard them on your D, or do you think they will be noisier:confused0:.

Thanks for the info:smile:

I too am curious why you think these would be noisier. Is it a vibration you're talking about? A sound of rushing air?

I've got Wilwood drilled, slotted, and ventilated disc brakes on the front of my car and I've noticed no difference in sound at all.

[dn010]

I've had the DAP (Harvey) discs on my car for almost 10 years, I don't remember what pads I have currently but I've tried multiple brands (never Reds though).

These rotors are noisy (kind of sounds like a loud ZZZZzzzz high pitch to low with brakes applied until you stop; almost like someone is using a circular saw nearby) and I get a high pitched squeal from them at lower speed stops even with shims. Evident from the length of time I've had them - I like them better over OEM even with the issues. I'm sure they run cooler (doubt by 250); but they will STILL fade with some heavier driving/braking.


I too am curious why you think these would be noisier. Is it a vibration you're talking about? A sound of rushing air?

I've got Wilwood drilled, slotted, and ventilated disc brakes on the front of my car and I've noticed no difference in sound at all.

[hillbillydmc]

I've had the DAP (Harvey) discs on my car for almost 10 years, I don't remember what pads I have currently but I've tried multiple brands (never Reds though).

These rotors are noisy (kind of sounds like a loud ZZZZzzzz high pitch to low with brakes applied until you stop; almost like someone is using a circular saw nearby) and I get a high pitched squeal from them at lower speed stops even with shims. Evident from the length of time I've had them - I like them better over OEM even with the issues. I'm sure they run cooler (doubt by 250); but they will STILL fade with some heavier driving/braking.

Thanks so much, this was the info I needed:bigclap:

[DCUK Martin]

EBC May say you can combine redstuff pads with drilled rotors but they don't know the delorean. For a high performance car it makes sense on some level but for us, you're making up for poor oem brakes. It's a different scenario.

[Henrik]

I was curious about the purpose of drilled/slotted rotors so I googled it. I though it had to do with expelling water during braking in the rain but I was surprised after my 30 second research that it is supposedly for providing a way for gases and brakes dust to escape during braking. Is that correct?

Ventilated rotors - yes. But drilled and slotted? Are those features really worth it on a Delorean? Seems like you're asking for pad wear (and noise as someone pointed out) for no specific gain, other than the cool factor.

Just wondering.

[ccurzio]

Also the website says they run 250 degrees cooler.

Any numbers quoted by Hervey need to be taken with the biggest grain of salt you can find.

[dn010]

I was curious about the purpose of drilled/slotted rotors so I googled it. I though it had to do with expelling water during braking in the rain but I was surprised after my 30 second research that it is supposedly for providing a way for gases and brakes dust to escape during braking. Is that correct?

Ventilated rotors - yes. But drilled and slotted? Are those features really worth it on a Delorean? Seems like you're asking for pad wear (and noise as someone pointed out) for no specific gain, other than the cool factor.

Just wondering.


As far as I'm concerned, getting crossed drilled/slotted rotors over blanks is more of an "looks" thing rather than anything performance related. They MAY run SLIGHTLY cooler and you MAY get less fade as fast compared to blanks, but thats really it and would have to be measured/tested to see if those claims are 100% correct. I went from original blanks that were "warped" and rusted to the drilled/slotted with new pads so I immediately felt a difference - doesn't mean that the new rotors were any better, they were just new.

Unless I'm mistaken on this as well: I don't even think there are brake pads that will even give off excess gasses with the compounds they use now.

You will have the noise, possibility of cracking, and I can say with a good bit of confidence that they will not run 250 degrees cooler. So,I'd say that with blank v. drilled/slotted it is a matter of preference, not a matter of performance. That said, I didn't buy these so I could not have fade going from 88mph to 0 on a daily basis; 10+ years ago it was just another thing I could do to make my car look different compared to others, long before all the mods and everything else was being done like today.

[NightFlyer]

You guys can actually see the rotors through our wheels?

You guys are good :biggrin:

[Nicholas R]

You guys can actually see the rotors through our wheels?

You guys are good :biggrin:

I was thinking the same thing, lol.


I was curious about the purpose of drilled/slotted rotors so I googled it. I though it had to do with expelling water during braking in the rain but I was surprised after my 30 second research that it is supposedly for providing a way for gases and brakes dust to escape during braking. Is that correct?

Ventilated rotors - yes. But drilled and slotted? Are those features really worth it on a Delorean? Seems like you're asking for pad wear (and noise as someone pointed out) for no specific gain, other than the cool factor.

Just wondering.

Each brake disc feature has it's own purpose. Slots really help to keep pad wear even so that you have full, even contact. Drilled holes are for the ventilation of gasses as well as for cooling. The ventilation is for heat dissipation only. (though these are not ventilated rotors).

[dn010]

You guys can actually see the rotors through our wheels?

You guys are good :biggrin:

Would be tough with stock wheels; the rears - no way, the fronts, you can get a good peak if they rotors are new and plated & you are parked in the sunshine. Get custom wheels and you can see everything depending on the style of course. Back when I got these I had the nice new plated rotors and rebuilt calipers that were painted red, it did look good even behind stock wheels. Now, everything is rusty, my windshield is smashed, frame rotten but at least I have the EFI taken care of :D

[NightFlyer]

Would be tough with stock wheels; the rears - no way, the fronts, you can get a good peak if they rotors are new and plated & you are parked in the sunshine. Get custom wheels and you can see everything depending on the style of course. Back when I got these I had the nice new plated rotors and rebuilt calipers that were painted red, it did look good even behind stock wheels. Now, everything is rusty, my windshield is smashed, frame rotten but at least I have the EFI taken care of :D

Gotta have priorities :smile:

[DMCVegas]

Since I've ran cross- drilled rotors on my car, I'll chime in on this one.

Yes, they're a bit noisier. It sounds like a turbine winding down when you brake, so depending on if you like that it that can be a bonus. They can also help eliminate brake fade, sure. But the biggest problem is with cross-drilled rotors that they can crack and have a much shorter lifespan.

Using them in a daily driver as well as routinely cranking the car up into the triple digits on rural highways, I can tell you that the best benefit I ever got from braking wasn't from the rotors. It was when I flushed out my hydraulic fluid. I also replaced my brake hoses, and went overkill with Stainless Steel Braided hoses from Goodridge. That was a night and day difference on braking power. I would recommend putting money into replacing your brake hoses and flushing out all that old DOT4 fluid first before any other upgrades. Especially if you want instant results. Some will debate the benefits of upgrading to SS brake hoses, but the key is just to get those hoses and that fluid replaced.

[dn010]

Since I've ran cross- drilled rotors on my car, I'll chime in on this one.

Yes, they're a bit noisier. It sounds like a turbine winding down when you brake, so depending on if you like that it that can be a bonus. They can also help eliminate brake fade, sure. But the biggest problem is with cross-drilled rotors that they can crack and have a much shorter lifespan.

Using them in a daily driver as well as routinely cranking the car up into the triple digits on rural highways, I can tell you that the best benefit I ever got from braking wasn't from the rotors. It was when I flushed out my hydraulic fluid. I also replaced my brake hoses, and went overkill with Stainless Steel Braided hoses from Goodridge. That was a night and day difference on braking power. I would recommend putting money into replacing your brake hoses and flushing out all that old DOT4 fluid first before any other upgrades. Especially if you want instant results. Some will debate the benefits of upgrading to SS brake hoses, but the key is just to get those hoses and that fluid replaced.

+1 on that, I upgraded my hoses to SS braid too when I did my whole brake system so that was another thing that made a difference.

I also like how they look compared to the original hoses :giggle:

[Henrik]

+1 on that, I upgraded my hoses to SS braid too when I did my whole brake system so that was another thing that made a difference.

I also like how they look compared to the original hoses :giggle:

I have flushed my brake system and replaced my brake hoses too, but why would SS braided hoses have any influence on brake performance?

[dn010]

I'm usually wrong, but my understanding is that the stainless braid keeps the lines from expanding when you hit the brakes.

[Gfrank]

I didn't purchase mine (on the car when I got it) but they sure look the same, noisy as all hell (echo off buildings etc, can't much hear it on open road) Zzzzzzzz. No idea why, never had another set do it

[DMCVegas]

I'm usually wrong, but my understanding is that the stainless braid keeps the lines from expanding when you hit the brakes.

Correct. And the argument against them is that most people on the street will never get their brake fluid hot enough to cause good condition rubber to expand. Like I said, I used to routinely run at high speeds on deserted highways in the desert, so I figured that a little extra protection wouldn't hurt. But how much additional braking power, if any, that I gained may not ever be known. Though while I've also no problem with most NOS parts, things like brake lines I'm not comfortable with running old stuff from Dunmurry on my car. So that was again a personal choice.

[Mark D]

I echo the statement about the stainless brake lines... I have them on my car but not so much as a "performance" upgrade but rather to replace the aged stock components that were looking questionable after 33 years of use.

I doubt anyone would be able to feel the difference between OE brake hoses and SS braided under most driving conditions. Maybe on a track or on the street with lots of hard repeated braking, but then I'd speculate that you'd feel the effects of friction/pedal fade before you'd feel any contribution from expanding hoses.