buying M3, have questions

Actually, Military Sales offices in Germany are affiliated with host nation dealerships, so you can see some of the cars, and speak with a competent sales rep, etc.

As for the Comp Package, I'll leave that one alone. I didn't feel it warranted waiting an extra 4-5 months for my car, but I did drop $2,100 for Individual paint, so what do I know?

Chief

Originally Posted by dawgbone

Finally.... someone that knows...Yes drilled rotors do in fact cool faster, but, they also heat up quicker...And the main purpose of the holes are to rid of the gases between the pads/rotors..

Regardless, I couldn't see you putting the rotors under that much stress(actual race conditions), as to the point of cracking them...The only reasons that they should crack would be 1) too small of diameter or 2) you're coming into corners too hot, and/or you don't know the limits of your brakes, and refuse to conserve them...

The drill rotors do perform, but with the right applications..I personally think that both the standard rotor and the drilled rotors, are too small..Probably the best upgrade (mod) as far as breaks on an e46, would be new stainless lines and decent brake fluid...Most probably, you will never have an issue with them..unless your left foot gets bored(SMG) and you let it sleep on the left peddle while driving through puddle of water

Oh...and drilled rotors do look good too

Actually they don't cool faster. AIr doesn';t move through the wholes except possibly when you are stopped. Maybe in the days of soild rotors, but with entilated rotors the air moves radially through the rotor and hole don'
t do anything, except start cracks.

And many race teams, as well as people who track rotors with holes in them, find them cracking between holes.

You under estimate the potential of a stock E46 M3. You are talking about a car that one street tires is good for 145 at the Glen and 135 at VIR (two place on the full track), and over 140 at Summit Point, and weighs some 3400 pounds with people on board. Add in R-comp tires and any form of suspension upgrade, and you are talking even higher speeds into braking zones. The car is bloddy FAST, and bloody HEAVY. LOTS of brake energy.

SS brakes lines don't do anything for dealing with heat. They do enhance pedal feel by eliminating one more area of flex in the system.

Originally Posted by Pinecone

Actually they don't cool faster. AIr doesn';t move through the wholes except possibly when you are stopped. Maybe in the days of soild rotors, but with entilated rotors the air moves radially through the rotor and hole don'
t do anything, except start cracks.

And many race teams, as well as people who track rotors with holes in them, find them cracking between holes.

You under estimate the potential of a stock E46 M3. You are talking about a car that one street tires is good for 145 at the Glen and 135 at VIR (two place on the full track), and over 140 at Summit Point, and weighs some 3400 pounds with people on board. Add in R-comp tires and any form of suspension upgrade, and you are talking even higher speeds into braking zones. The car is bloddy FAST, and bloody HEAVY. LOTS of brake energy.

SS brakes lines don't do anything for dealing with heat. They do enhance pedal feel by eliminating one more area of flex in the system.

Pinecone, since I consider you to be the expert here, tell me if I made a mistake in upgrading my brakes to the slotted Dinan (Brembo GT) front and rear binders. Other than spending way to much money that is. BTW They come with Ferodo pads. I'd value your opinion.

Only downside of slotting is less pad life. The slots act as a lathe to grind the pads off a bit quicker. The idea on the race track is that they scrape off any glazing that might occur.

Also if there is any pad outgassing, the slots will carry that away also. But not a problem with modern pads, except BRAND new ones. Once they are bedded no problem.

For the street, a MUCH better choice than drilled, but the best overall is really just normal rotors.

So, I wouldn't say you made a big mistake, but maybe a very small one.

Ferodo was a very big name in pads, but not heard from much lately. But if they are working well, then they are working well. The things I look for in pads is good initial bite, linear feel, low dust (for street) and low noise (also for street). And pretty much in that order.

Originally Posted by Pinecone

Only downside of slotting is less pad life. The slots act as a lathe to grind the pads off a bit quicker. The idea on the race track is that they scrape off any glazing that might occur.

Also if there is any pad outgassing, the slots will carry that away also. But not a problem with modern pads, except BRAND new ones. Once they are bedded no problem.

For the street, a MUCH better choice than drilled, but the best overall is really just normal rotors.

So, I wouldn't say you made a big mistake, but maybe a very small one.

Ferodo was a very big name in pads, but not heard from much lately. But if they are working well, then they are working well. The things I look for in pads is good initial bite, linear feel, low dust (for street) and low noise (also for street). And pretty much in that order.

Thanks, I feel better. I think. They seem to work great. It may be my imagination, but they do seem to slow me down quicker.

I'm not an M3 owner (yet - hopefully this summer) but I was reading this thread and wanted to comment on the cross drilled rotors. Apparently many people had problems with cracking when the holes were actually DRILLED into the rotors therefore weakening the structure. The better "cross-drilled" rotors from what I am told are actually forged with the holes in them making one solid structure less prone to metal fatigue.

I was looking at the PDF file on the competition package and they said that the cross-drilled may make more noise than the regular rotors - is that the case? I personally think they look cool (and are almost 1" bigger) but I'm a big fan of symmetry. If they were cross-drilled in both the front AND the back I would like it better.

The other concern of mine is that performance brakes are usually meant for the track and do not necessarily perform the same way. My friend put performance pads and power slot rotors on his car and stated that they did not really start grabbing until they heated up and almost caused an accident when pulling out of a parking spot. Not to say that the BMW brakes would be the same as those.

Originally Posted by spta97

Apparently many people had problems with cracking when the holes were actually DRILLED into the rotors therefore weakening the structure. The better "cross-drilled" rotors from what I am told are actually forged with the holes in them making one solid structure less prone to metal fatigue.

They can't be "one solid structure" with holes in them.

If they were cross-drilled in both the front AND the back I would like it better.

I guess it's your lucky day.

The other concern of mine is that performance brakes are usually meant for the track and do not necessarily perform the same way.

Don't worry...the car is not intended for track use.

Originally Posted by bren

They can't be "one solid structure" with holes in them.

Here's a quote that explains it better:

"The drilled rotor so common on the Porsche 930 turbo is NOT really drilled at all. It is a CAST hole. Porsche did this to help minimize the effects a hole has in creating a stress riser in the surface of the brake rotor. A drilled hole goes directly through and interrupts the grain structure of the metal. Where as a cast hole has the grain structure formed around it in an uninterrupted flow. All holes in a brake rotor will eventually show signs of stress cracking. A drilled hole will crack much sooner than a cast one"

Originally Posted by bren

I guess it's your lucky day.

From the Competition package PDF

"The cross-drilled, compound front rotors have been increased to 13.6" (up from 12.8"). "

I do not see any mention of the rear rotors being cross-drilled as well - is BMW incorrect?

Originally Posted by bren

Don't worry...the car is not intended for track use.

Again, reading the Competition package PDF:

"The M3’s already powerful brakes have been improved to meet the demands of repetitive hard braking experienced on the track."

Originally Posted by bren

Don't worry...the car is not intended for track use.

That would mean neither was the non ZCP M3, but quite a few people do it anyway.

Originally Posted by TD330ci

That would mean neither was the non ZCP M3, but quite a few people do it anyway.

Right. But they aren't misled by BMW into believing they bought some sort of track ready "race" car.

Originally Posted by spta97

Here's a quote that explains it better:

"The drilled rotor so common on the Porsche 930 turbo is NOT really drilled at all. It is a CAST hole. Porsche did this to help minimize the effects a hole has in creating a stress riser in the surface of the brake rotor. A drilled hole goes directly through and interrupts the grain structure of the metal. Where as a cast hole has the grain structure formed around it in an uninterrupted flow. All holes in a brake rotor will eventually show signs of stress cracking. A drilled hole will crack much sooner than a cast one"

You said forged...not cast. Those are vastly different processes.

From the Competition package PDF

"The cross-drilled, compound front rotors have been increased to 13.6" (up from 12.8"). "

I do not see any mention of the rear rotors being cross-drilled as well - is BMW incorrect?

No, what you didn't see mention of was an increase in rotor size for the rear. Where does it say the rears are not drilled?

Again, reading the Competition package PDF:

"The M3’s already powerful brakes have been improved to meet the demands of repetitive hard braking experienced on the track."

Go ahead and track the ZCP and try to get the rotors replaced under warranty. BMW clearly states that any track time will void your warranty. Next time you watch an auto race check to see how many cars actually still use drilled rotors. They will crack when used on the track as is clearly stated in your quote above "All holes in a brake rotor will eventually show signs of stress cracking. A drilled hole will crack much sooner than a cast one"

Originally Posted by bren

Right. But they aren't misled by BMW into believing they bought some sort of track ready "race" car.

Well to the total idiot who does not know any better. They probably should not be tracking them at that point anyway.

I know it's not "track" ready but it's no furhter off then the non-ZCP.

No worse then Mits advertising the rally capabilities of the EVO and then refusing all warranty claims because of such use.

Besides the cross-drilling, the ZCP rotors are also floating rotors with aluminum hats. The hats reduce weight, but are prone to cracking as well, and must be checked periodically. I believe that because of liability fears of hat fatigue, the Euro M3 brakes weren't offered in the US initially. The floating rotor accommodates heat expansion radially so the braking surface stays planar instead of bowed.

--Andre

Also realize there are performance pads and performance pads.

There are street performance pads that work fine cold. Maybe not quite as well as stock BMW pads, but still fine for street use. Less dust many itme, low noise, but better high temperature performance.

Then there are track biased performance pads. Most of these take a good bit of heat to work. NOT good for street use, since you often have cold pads with virtually no bite. Also these tend to make a lot of noise and a LOT of dust, which may be corrosive adn ruin wheels and paint jobs if not washed off promptly.

There are a few pads with reasonble cold bite that hold up on the track. But they are few.

The rotors had nothing to do with it, he picked the wrong pads.

Originally Posted by Andre Yew

Besides the cross-drilling, the ZCP rotors are also floating rotors with aluminum hats. The hats reduce weight, but are prone to cracking as well, and must be checked periodically. I believe that because of liability fears of hat fatigue, the Euro M3 brakes weren't offered in the US initially. The floating rotor accommodates heat expansion radially so the braking surface stays planar instead of bowed.

--Andre

Actually the euro brakes were not offered in the US due to concerns about complaints about noisy brakes. BMW figures most Americans are pretty much idiots when it comes to cars. Unfortunately, in many cases they are absolutely correct.

there is so much talk about wheels and brakes. Both are essentially parts bin items that any M3 can update down the road for a price.


the steering rack is the only piece that can't be bought/fitted later because of the sensors/electronics/DME's that need to be updated. this might be the best reason to get the package, but many keep saying that it is only a marginal difference.

thoughts?

Originally Posted by RChoudry

there is so much talk about wheels and brakes. Both are essentially parts bin items that any M3 can update down the road for a price.


the steering rack is the only piece that can't be bought/fitted later because of the sensors/electronics/DME's that need to be updated. this might be the best reason to get the package, but many keep saying that it is only a marginal difference.

thoughts?

That is the ONLY item that interests me.

I really have to go drive one...although everything I've read from people who have actually owned/driven both says that the difference is negligible.

yeah, it seems odd that the one thing the car needs to improve, $4000 doesn't seem to do much for.

anybody with a ZCP M3 able to tell a difference?

and boy would I be pissed if they added it to the base model this year!!

Originally Posted by RChoudry

yeah, it seems odd that the one thing the car needs to improve, $4000 doesn't seem to do much for.

The thing the car needs to improve is to lose weight...a lot of weight.

We can do that. When are we stripping your car out?

Originally Posted by bren

No, what you didn't see mention of was an increase in rotor size for the rear. Where does it say the rears are not drilled?

[/I]

I did not see anything that says that the rear rotors have changed in diameter or are cross drilled. Only having bmwusa.com to go by I don't know what the answer is.

Perhaps someone who has the ZHP M3 knows the answer?

Originally Posted by spta97

Perhaps someone who has the ZHP M3 knows the answer?

I thought that I already told you the answer

Originally Posted by bren

I thought that I already told you the answer

Damn those wheels look nice.

Alex

Yeah, and BMWUSA.com says the ZCP package has forged wheels and 8.5 inch fronts. BOTH are wrong.

But those wheels DO look nice. Are the offsets th same as stock? I wonder if you can run rears all around?