Thoughts on cross drilled rotors
Pro
Joined: Sep 2008
Posts: 694
Likes: 27
From: St James New York
No one has mentioned in the replies that there are, I beleive, 2 different manufacturing techniques for cross drilled rotors, cast and drilled. the cast are the most superior because in drilled rotors the metal is weakened due to the drilling. The cast is made as one peice therefore no weakening of the unit cause its made as one peice. Porches and Mercs use cast rotors and they'll wear surface material away before ever cracking.
If your not racing, quality cast and machined cross-drilled rotors are fine for the street, even if you like to push your C4 really hard!
Last edited by mako41; Aug 1, 2011 at 11:20 PM.
Melting Slicks
Joined: Feb 2011
Posts: 2,322
Likes: 6
From: Los Altos CA
Install HAWK HPS Ferro - Carbon Brake pads front & rear.
Its best $$ lower dollar brake upgrade you can do to your C4.
They work great with the stock Corvette brake Rotors.
No break fade ever noticed by me with those brake pads on my 87 Vert.
I drive fast most of the time too.
If you have extra $$$, buy quality slotted brake rotors.
BR
Its best $$ lower dollar brake upgrade you can do to your C4.
They work great with the stock Corvette brake Rotors.
No break fade ever noticed by me with those brake pads on my 87 Vert.
I drive fast most of the time too.
If you have extra $$$, buy quality slotted brake rotors.
BR
My mechanic said I need new pads so I've requested the Hawk HPS per your suggestion. I'm looking forward to some better stops.
Wayne
Safety Car
Joined: Feb 2000
Posts: 4,562
Likes: 106
From: Austin Texas
No such thing as rotors that have holes "cast" into them. Thats an internet myth. All cross-drilled rotors from every manufacturer are machined/drilled after the rotor has been cast.
If your not racing, quality cast and machined cross-drilled rotors are fine for the street, even if you like to push your C4 really hard!
If your not racing, quality cast and machined cross-drilled rotors are fine for the street, even if you like to push your C4 really hard!
Porsche GT2/GT3 rotors are CAST with the holes in them, which is why they don't crack under high stress.
After casting they drill & chamfer the "holes" to clean them up and they last far longer than traditional drilled rotors.
They seem to last the Porsche cars for 24-hour endurance races quite fine...
Some references:
You slide on the specially selected Genuine Porsche Big Brake 2-piece Cast-Hole rotors,
Last edited by 1991Z07; Aug 3, 2011 at 11:08 PM.
Le Mans Master
Joined: Sep 2006
Posts: 6,050
Likes: 147
From: Phoenix AZ
2021 C4 of the Year - Modified Finalist
When I put C5 brakes on my 86, I used the factory rotors that I took off my C5. My C5 has 35,000 miles on it since I changed them to drilled and slotted, and I am not hard on brakes. My C4 has 18,000 miles on it since I put the C5 brakes on it, and changed the rear pads.
I am way harder on the C4 than the C5 because I don't want to change the clutch any time soon on the C5. What a job!
Anyway, the 86 is a lot more fun to drive with bigger brakes. And since I have solid rotors, not drilled or slotted, they do just fine, but I would like the added "bling".
If you do not put C5 brakes on your car, you are missing a great upgrade. Don't waste a dime on C4 brakes. They just aren't big enough for how we drive.
I am way harder on the C4 than the C5 because I don't want to change the clutch any time soon on the C5. What a job!
Anyway, the 86 is a lot more fun to drive with bigger brakes. And since I have solid rotors, not drilled or slotted, they do just fine, but I would like the added "bling".
If you do not put C5 brakes on your car, you are missing a great upgrade. Don't waste a dime on C4 brakes. They just aren't big enough for how we drive.
Pro
Joined: Sep 2008
Posts: 694
Likes: 27
From: St James New York
Nice try...but WRONG!
Porsche GT2/GT3 rotors are CAST with the holes in them, which is why they don't crack under high stress.
After casting they drill & chamfer the "holes" to clean them up and they last far longer than traditional drilled rotors.
They seem to last the Porsche cars for 24-hour endurance races quite fine...
Some references:
http://www.928gt.com/showproduct.aspx?productid=4934
Porsche GT2/GT3 rotors are CAST with the holes in them, which is why they don't crack under high stress.
After casting they drill & chamfer the "holes" to clean them up and they last far longer than traditional drilled rotors.
They seem to last the Porsche cars for 24-hour endurance races quite fine...
Some references:
http://www.928gt.com/showproduct.aspx?productid=4934
Your link is complete marketing BS! You mention Porche GT2's/GT3's but then provide a link to aftermarket rotors for 70's era Porche 928's. Those rotors don't have holes "cast" into them, they are x-drilled and machined from a solid blank just like every other x-drilled rotor made. If you were familiar with modern casting processes you would know that the x-drilled holes on the rotors linked too are to numerous, to close together, and to close to the edge of the rotors to have been "cast" into the rotor.
Here's an interesting read on the topic http://corner-carvers.com/forums/sho...ght=cast+holes
Any brake suppilers or braking experts want to chime in ....feel free!
Last edited by mako41; Aug 4, 2011 at 05:02 PM.
Safety Car
Joined: Feb 2000
Posts: 4,562
Likes: 106
From: Austin Texas
Really! I don't think so!
Your link is complete marketing BS! You mention Porche GT2's/GT3's but then provide a link to aftermarket rotors for 70's era Porche 928's. Those rotors don't have holes "cast" into them, they are x-drilled and machined from a solid blank just like every other x-drilled rotor made. If you were familiar with modern casting processes you would know that the x-drilled holes on the rotors linked too are to numerous, to close together, and to close to the edge of the rotors to have been "cast" into the rotor.
Here's an interesting read on the topic http://corner-carvers.com/forums/sho...ght=cast+holes
Any brake suppilers or braking experts want to chime in ....feel free!
Your link is complete marketing BS! You mention Porche GT2's/GT3's but then provide a link to aftermarket rotors for 70's era Porche 928's. Those rotors don't have holes "cast" into them, they are x-drilled and machined from a solid blank just like every other x-drilled rotor made. If you were familiar with modern casting processes you would know that the x-drilled holes on the rotors linked too are to numerous, to close together, and to close to the edge of the rotors to have been "cast" into the rotor.
Here's an interesting read on the topic http://corner-carvers.com/forums/sho...ght=cast+holes
Any brake suppilers or braking experts want to chime in ....feel free!
That link was a 928 brake upgrade to GT2/GT3 rotors...
Must be HUNDREDS of links out there about the GT2/GT3 rotors...I picked the first one in Google I came to. You have to carefully select the search...the new GT3's have PCCB rotors, so if you search for "Porsche GT3 CUP rotors" you'll get all kinds of information about the new Carbon Ceramic rotors, NOT the STEEL rotors of the previous generation.
They WILL eventually crack, but will outlast traditional "drilled" rotors by a large margin.
Porsche has used them for years...and it is a closely guarded secret how it is done.
It's one of the main reasons that Porsche has killed the rest of the manufacturers in the GT2/GT3 ranks (over time).
Their brakes are LEGENDARY for a reason...because they work, and work well.
I found PLENTY of references from REAL OWNERS about the inside of the "drilled" portions being a "CAST" consistency, NOT smooth like they had been drilled out.
Believe what you want...it's obvious your mind is already made up on this issue.
Last edited by 1991Z07; Aug 6, 2011 at 09:42 PM.
Pro
Joined: Sep 2008
Posts: 694
Likes: 27
From: St James New York
Sorry, didn't realize you had a reading comprehension issue...
That link was a 928 brake upgrade to GT2/GT3 rotors...
Must be HUNDREDS of links out there about the GT2/GT3 rotors...I picked the first one in Google I came to. You have to carefully select the search...the new GT3's have PCCB rotors, so if you search for "Porsche GT3 CUP rotors" you'll get all kinds of information about the new Carbon Ceramic rotors, NOT the STEEL rotors of the previous generation.
They WILL eventually crack, but will outlast traditional "drilled" rotors by a large margin.
Porsche has used them for years...and it is a closely guarded secret how it is done.
It's one of the main reasons that Porsche has killed the rest of the manufacturers in the GT2/GT3 ranks (over time).
Their brakes are LEGENDARY for a reason...because they work, and work well.
I found PLENTY of references from REAL OWNERS about the inside of the "drilled" portions being a "CAST" consistency, NOT smooth like they had been drilled out.
Believe what you want...it's obvious your mind is already made up on this issue.
That link was a 928 brake upgrade to GT2/GT3 rotors...
Must be HUNDREDS of links out there about the GT2/GT3 rotors...I picked the first one in Google I came to. You have to carefully select the search...the new GT3's have PCCB rotors, so if you search for "Porsche GT3 CUP rotors" you'll get all kinds of information about the new Carbon Ceramic rotors, NOT the STEEL rotors of the previous generation.
They WILL eventually crack, but will outlast traditional "drilled" rotors by a large margin.
Porsche has used them for years...and it is a closely guarded secret how it is done.
It's one of the main reasons that Porsche has killed the rest of the manufacturers in the GT2/GT3 ranks (over time).
Their brakes are LEGENDARY for a reason...because they work, and work well.
I found PLENTY of references from REAL OWNERS about the inside of the "drilled" portions being a "CAST" consistency, NOT smooth like they had been drilled out.
Believe what you want...it's obvious your mind is already made up on this issue.
is explored pretty extensively.Maybe you missed the part about people who work in modern casting foundries who all state casting that type of hole into a brake rotor is not really possible. If your that confident I am mistaken and you are correct why don't you try to collect the cash bounty being offered for the first person to "prove definitively" that any manufacturer actually makes a brake rotor, (Porche included!) with holes cast into them! Free money for you, Right?? Go for it.
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