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-   -   Where to get cross drilled Rotors E70 (https://xoutpost.com/bmw-sav-forums/x5-e70-forum/70786-where-get-cross-drilled-rotors-e70.html)

London Lad 03-05-2010 07:15 PM

The McLaren F1 is an old car now. With moden pad and disc materials there are no benefits to having holes in discs on road cars. Most high performance track cars (inc F1 cars) are using ceramics now.

You only have to read through this forum to see how widespread the current fashion for throwing expensive bolt on accessories, with no performance value, at cars is. Its hardly surprising the car manufactures have jumped on the band wagon, it's a massively lucrative market.

FSETH 03-05-2010 07:19 PM

1 Attachment(s)
Quote:

Originally Posted by Noodle555 (Post 720126)
Yes, you're right. You know better than the engineers of all the top sports car manufacturers including Gordon Murray the designer of the McLaren F1. Incidentaly Gordon Murray also designs F1 race cars including the McLarens. When he designed the F1 car he wanted it to tbe the best in every aspect possible but damn did he ever mess up with the brakes as he used drilled ones. Doesn't he know about brake fade :rolleyes:

:wavey:

I never said I knew better than anyone else. The F1 used a Brembo big brake kit, which is very different than OE replacement rotors. More than likely these rotors were disigned to be oversized to make up for the decreased metal mass drilling requires. Not to mention the extensive brake cooling ducts applied to that car.

If you want to spend the money to add a big brake kit, that is one thing, but I would not replace my plain stock disks with cross-drilled ones.

Here is what a well known vendor has to say on the issue of direct replacement slotted/drilled rotors and high speeed use;

Noodle555 03-05-2010 07:26 PM

Quote:

Originally Posted by FSETH (Post 720129)
I never said I knew better than anyone else. The F1 used a Brembo big brake kit, which is very different than OE replacement rotors. More than likely these rotors were disigned to be oversized to make up for the decreased metal mass drilling requires.

Here is what a well known vendor has to say on the issue of direct replacement slotted/drilled rotors and high speeed use;


Simply a disclaimer for liability reasons. The Brembo BBK has a similar disclaimer in the kit to inspect the brakes carefully between use. Ask me how I know. Does that mean they don't provide superior braking at the track? Heck no. Ask any track enthusiast.

Quicksilver 03-05-2010 07:48 PM

As far as where to get cross drilled rotors?

I saw them hanging up as part of a display
along with an exhaust system displayed
at the dealership yesterday.

FSETH 03-05-2010 07:54 PM

Quote:

Originally Posted by Noodle555 (Post 720133)
Simply a disclaimer for liability reasons. The Brembo BBK has a similar disclaimer in the kit to inspect the brakes carefully between use. Ask me how I know. Does that mean they don't provide superior braking at the track? Heck no. Ask any track enthusiast.

:thud:You do realize the difference between big brake kits and direct replacement rotors, right? Please do not tell me that you think slapping on slotted/drilled rotors that are the same exact size as OEM (aka direct replacement rotors) are a performance upgrade? Especially for track use.

Big brake kits typically consist of multi-piston calipers and additional features that increase performance. The main gain does not come from the rotors being slotted/drilled. That is where the weight savings aspect of cross drilled comes into play.

Noodle555 03-05-2010 08:10 PM

Answer me this. Why do companies like AP Racing and Brembo have packages for race applications, not for reglar street cars but for purpose made race cars, that come drilled or slotted and are floating. From your own words the greater mass would ensure no brake fade under race conditions. Why don't they have the same size rotor with no vanes or holes, beacuse according to your logic that would provide better braking?

Fact is that drilled or slotted provide superior braking by being lighter and being able to expell gasses. However, they are prone to overheat and that's why there are brake cooling kits.

The end.

Have a nice weekend :D

FSETH 03-05-2010 08:49 PM

Quote:

Originally Posted by Noodle555 (Post 720141)
Answer me this. Why do companies like AP Racing and Brembo have packages for race applications, not for reglar street cars but for purpose made race cars, that come drilled or slotted and are floating. From your own words the greater mass would ensure no brake fade under race conditions. Why don't they have the same size rotor with no vanes or holes, beacuse according to your logic that would provide better braking?

Fact is that drilled or slotted provide superior braking by being lighter and being able to expell gasses. However, they are prone to overheat and that's why there are brake cooling kits.

The end.

Have a nice weekend :D

I would prefer you answer the questions from my last post first before I go any further with you. Thanks.

Penguin 03-05-2010 08:57 PM

Quote:

Originally Posted by Noodle555 (Post 720141)
act is that drilled or slotted provide superior braking by being lighter and being able to expell gasses. :D

Please educated me as to why being lighter would provide superior braking? I can see there would be suspension advantages to keeping unsprung weight down, but the only effect I can see a lighter or heavier disk would have on actual braking performance would be the moment of inertial, which on the top of my head would not be a very big energy difference, considering the diameter of the disk and the weight involved, in relation to the total mass you are slowing down.

What am I missing here?

P.S. Perhaps my guess as to the rotational inertial/energy of a rotating brake disk is wrong... when I get some spare time maybe I'll do the calculation and see if I've underestimated the delta effect of the mass removed by drilling/slotting. But if somebody already knows, you could save me some time and effort by chiming-in with the answer.

Quicksilver 03-05-2010 09:04 PM

This part struck my funny bone. I didn't know drilled
or slotted expelled gas............:rofl:


Quote:

Originally Posted by Noodle555 (Post 720141)
Fact is that drilled or slotted provide superior braking by being lighter and being able to expell gasses.:D


JCL 03-05-2010 09:30 PM

Quote:

Originally Posted by Noodle555 (Post 720083)
Just think about it the top brake manufacturers of the world have performance brake packages. Do you think their engineers are going for looks or function? Same goes for sport car manufacturers, look at the stock rotors for the Ferrari 458.

Quote:

Originally Posted by JCL
As to the top vehicles like Ferrari (and Porsche), they are going for looks and function with their brake designs. You can tell, because they offer brake calipers in many colours. Try and explain that away as a functional improvement.

Quote:

Originally Posted by Noodle555
People chose colours of everything these days. How does that affect performance. I am not following your logic.

I said they were going for looks and function. If they were only concerned about function, they wouldn't be offering colour coordinated calipers, which are purely for looks. You seemed to be implying that it is one or the other, and that the designers were only concerned about performance. Designers can be motivated by performance and cosmetics, so having holes cast in the rotors doesn't mean that those rotors have better performance, it may mean that the designers were motivated to attract purchasers who thought they would have better performance.


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