slotted and or drilled rotors

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69DARTS

69DARTS

69 Darts Rule
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i am kicking around the idea .
of putting slotted or drilled rotors on my 72 duster.
its all ready 4.5 bolt pattern
all i want to do is put the rotors on with out changing anything else.
can i just buy the rotors and where can i get them
thanks
 
How are your rotors now? If they are in good shape, why not drill or slot the ones you have? Just a thought.
 
Hello, I sell an Aluminum template so you can do it at home on your drillpress and still have it come out nice and even. $40 shipped.
 
There is really no benefit to drilled, slotted or dimpled rotors except for looks. The days of out gassing pad compounds are over.

Are you looking for better braking performance?
 
dano said:
There is really no benefit to drilled, slotted or dimpled rotors except for looks. The days of out gassing pad compounds are over.

Are you looking for better braking performance?
Click to expand...

I think what you are talking about happens with organic pads. Since organic pads are still available, it's still a possibility. I could be mistaken, but I think that's right. I sell organic pads almost everyday.
 
You can grind slots in brake pad material much easier.

Heat is a function of brake performance.

Or just buy better brake pads instead.
What do you have now?
 
I bought them in Centrix (drilled and slotted ) from Rock Auto for my GTS project. Pretty reasonable too
 
dano said:
There is really no benefit to drilled, slotted or dimpled rotors except for looks. The days of out gassing pad compounds are over.

Are you looking for better braking performance?
Click to expand...

Then why do you see this on almost all race cars (picture is of a Rousch NASCAR brake).
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69_340_GTS said:
Then why do you see this on almost all race cars (picture is of a Rousch NASCAR brake).
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Click to expand...

From what I've gathered in the past on this debate, the high speeds is the big difference why race cars benefit from drilled rotors more than do cars getting normal street use.
 
dano said:
There is really no benefit to drilled, slotted or dimpled rotors except for looks. The days of out gassing pad compounds are over.

Are you looking for better braking performance?
Click to expand...

^Yup, snake oil. /thread
 
It's not snake oil if your under extreme conditions.
Daily drivers, hot rods, street machines need not apply IMO.
They just don't meet the heavy loads and abuse to bennifit from the drilled and slotted rotor.

A bigger disc, better pads & more Pistons in the caliper are a plus and more than likely all you'll need unless you actually race around in circles or a road course. I can also see there use in aong distance interstate ride.

But until that extreme level is reached, most every person I have met and read that used them complained about not actually seeing, feeling or actual measuring a better braking experience.
(Though none have mentioned anything about a cooler fluid temp or longer brake/rotor life.)
 
Thought I seen them in the most recent PST catalog. But when I tried to look it up on their website for my car a week or so ago I couldn't find them.

EDIT:

It's on page 41 if you have the catalog, tried to upload a pic of it but my phone is acting up. It's 79$ for two (I'm guessing fronts) then 129$ for four, which I'm guessing is for the fronts and rears. Plus you can get a 10% discount for FABO members if you spend 200$ :)
 
Seems like most of the race applications have gone to slotted rotors, like you see above, in favor of drilled rotors. The slots do a better job of cooling without as much structural compromise.

For a street car, it doesn't matter. You're not heating the brakes enough or cycling them rapidly enough for it to be an issue. If anything, you lose a little braking area. Not a noticeable amount, but hey.

That said, I have drilled and slotted rotors on both my Challenger and my Duster. My Challenger has the 11.75" mopar disks, and I can say that I've run both the plain and the drilled/slotted version of that disk and have never noticed a difference on the street. I only have them because they were on sale at Summit. :D My Duster has Dr. Diff's 13" brake kit, and it just came that way. I don't avoid drilled and/or slotted rotors, but I don't seek them out either, and I don't pay more for them.

Also, some places won't turn rotors that have been drilled or slotted. It can be done, but not everyone will do it. Just food for thought.
 
I have drilled and slotted rotors on the front of my car. Most of the high performance rotors come that way.
 

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Last time we updated Tim's Valiant we put drilled and slotted rotors on the front. Saved a bunch of weight and they seemed to work just fine at 150+ mph.
 

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AndyF said:
Last time we updated Tim's Valiant we put drilled and slotted rotors on the front. Saved a bunch of weight and they seemed to work just fine at 150+ mph.
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Oh I think they work great, don't get me wrong. And most of the high performance rotors do come that way, like I said that's what I have too.

I have noticed recently that the full race cars seem to be going to slotted rotors more, but that's just observational.

Still, that Valiant isn't exactly your average Mopar. Most folks don't need 6 piston Baer's either. But dang they do look nice!!! :thumbup: And I bet that thing stops on a dime. One of my favorite Mopars by far. :prayer:
 
Holes are evil. Rotors prematurely crack at the holes.
Slots are more of a pad cleaning thing than much of anything else. You see holes and/or slots on high end street cars purely because of marketing. Same is true of wilwood rotors, marketing delivers what the average, uninformed customer wants.

Modern pad compounds actually transfer an extremely thin layer (read: invisible) of pad material to the face of the rotor.

I've heard very good things about having the rotor cryogenically "heat"-treated. Both in braking performance and in life-span.

Better or improved braking comes from, in order of importance:
1) Good pad compound that is well matched to the use.
2) Larger rotor OD
3) Improved airflow to cool the rotors in the correct way (can do it wrong easily and damage them)
4) Extremely rare cases, a larger caliper piston area.
 
I used to sell a 13 inch conversion kits for Mopar cars that used an OEM Mercedes rotor. Those rotors had holes in them right off the factory floor. Porsche rotors also have holes in them. So if it is good enough for Mercedes and Porsche engineers then it is good enough for me. I'm pretty sure that the factory boys test the snot out of these parts so if the holes created cracks they wouldn't put these things on the high dollar cars.
 

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72bluNblu said:
Oh I think they work great, don't get me wrong. And most of the high performance rotors do come that way, like I said that's what I have too.

I have noticed recently that the full race cars seem to be going to slotted rotors more, but that's just observational.

Still, that Valiant isn't exactly your average Mopar. Most folks don't need 6 piston Baer's either. But dang they do look nice!!! :thumbup: And I bet that thing stops on a dime. One of my favorite Mopars by far. :prayer:
Click to expand...

Yeah, Tim's Valiant is kind of the high end of Mopar street drivers. It was a super fun car and then it turned into a real monster once we dropped the 427 stroker motor in there. He needed all the brakes that we could hang on there! That car would go 160 mph if you were brave enough to keep your foot in it. 160 mph in a Valiant is scary.
 
AndyF said:
I used to sell a 13 inch conversion kits for Mopar cars that used an OEM Mercedes rotor. Those rotors had holes in them right off the factory floor. Porsche rotors also have holes in them. So if it is good enough for Mercedes and Porsche engineers then it is good enough for me. I'm pretty sure that the factory boys test the snot out of these parts so if the holes created cracks they wouldn't put these things on the high dollar cars.
Click to expand...

There's also a big difference between holes and slots cast into the rotor or machined into the rotor. The worse of the two is almost always the machined rotors as you're discontinuing the grain structure of the material causing stress risers (slots and holes are already a stress riser by themselves). My bet is that those Mercedes and Porsche rotors have their slots and holes casted in the rotor. For a street car you won't really get much added benefit except for looks.
 
Holes are evil, rotors crack at the holes. Anything will crack at a hole, but the thermal growth of a rotor puts huge internal stresses in it and the holes are major stress risers.

An engineer designed those rotors, sure, but two things happened after that. Marketing said that the market wants holes in the rotors and made enough of a case for it with accounting that the engineers were over-ruled. BT, DT.
 
ntsqd said:
Holes are evil. Rotors prematurely crack at the holes.
Slots are more of a pad cleaning thing than much of anything else. You see holes and/or slots on high end street cars purely because of marketing. Same is true of wilwood rotors, marketing delivers what the average, uninformed customer wants.

Modern pad compounds actually transfer an extremely thin layer (read: invisible) of pad material to the face of the rotor.

I've heard very good things about having the rotor cryogenically "heat"-treated. Both in braking performance and in life-span.

Better or improved braking comes from, in order of importance:
1) Good pad compound that is well matched to the use.
2) Larger rotor OD
3) Improved airflow to cool the rotors in the correct way (can do it wrong easily and damage them)
4) Extremely rare cases, a larger caliper piston area.
Click to expand...

Not entirely accurate information. All brake material transfers itself to the rotor. It's why you turn rotors when doing a brake job and it's why you "bed in" your brakes when you do a brake job.

The deal with rotors cracking when they are cross drilled comes from the holes not being properly relieved and also compromising the vanes on vented rotors when they are drilled.

Is it needed on a street car? Not really. Then again, you haven't seen my wife drive.....
 
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