I have a 04 330 ci/41,500 mi. and I will in the near future be replacing the brakes. I will be assuming that I will need to replace the rotors at this time. I believe I do not need to repalce the the calipers. 1) I would like to replace the rotors with drill/slotted ones. What manufactuers would be recommend by club menbers who have made this change? 2) What pads would be recommended for this application. Thank You for your input. prlane@hotmail.com
Do you have an overheating problem with your brakes or do you just like wearing out your pads faster? Lots of choices. Depends on your usage.
I don"t have a overheating problem. The reason for the up grade was if I was going to be replacing rotors would it be better to replace the roters with the drilled rotors as oppose to staying with the factory rotors. I am not hard on my brakes normal driving.
If you are not doing any changes to the calipers, then the best way to effect better braking is thru new lines and brake pad choice. (and tire choice since brakes don't really stop your car, your tires do)
Thanks for the input you all have given some good insight to my decision to stay with stock rotors and look at which pads to replace when I do this maintenance . I like cool but it must bring more than just cool to be cost effective.
Brake UPgrades It has been my experience that on a street BMW that will not see any serious track or autocross duty brake pad upgrades are a compromise mainly limited to low dust ceramic pads or super quiet but dusty European pads such as the BMW OEM or Replacement pads. Upgrades for performance on the street will either compromise quietness and or cleanliness and will only increase braking performance on a BMW driven to the limits, Otherwise those stock pads or Euro made replacement pads are darn hard to beat. Now when we start to venture to the track with our BMW's and then only at a pretty serious level that is when the aftermarket track-only pads such as Hawk variants really shine and then start to make sense. On to rotors and although I hate to risk ruffling feathers here, when it comes to performance and on a track driven BMW... The high quality European made cross-drilled (cast) rotors and or grooved rotors absolutely do improve braking performance and are a very popular upgrade for both the E36 and E46 BMW. On top of that If a BMW is driven to the limits on a very regular basis at driving events you can financially justify replacing the entire at wheel braking components to go to a true high performance upgrade such as the Brembo big brake kit not just for a performance advantage but for a worry free and very long life component wear. Yes, looking cool cost money but so does improving BMW brake performance. For a street only car though, I think, Forgetaboutit Enjoy!
I'm not 'ruffled', but I am kind of surprised at your assertion. I would think that, for all the years I've been involved in playing with cars both on and off track, that I have never, ever seen any objective testing to prove this. I mean, I have a set of ATE Power Disks on my 535is - mostly because I bought it that way - and I have a spare set lying around that I bought years ago because I figured they were both cheap and probably couldn't hurt. But I am still not prepared to say that they're better in any way because there is simply no proof. If you have some objective reference, I'd love to see it.
Thanks again for all of your insights, I know my direction, my Bimmer is a weekend/daily driver I will spend my money wisely. Then I can move on to the Bilstens.
I agree 100% and would love to see some scientific measured testing. In fact if Satch would give up a few pages in an upcoming Roundel I would love to put something like that together as I'm quite sure we could get some support from vendors etc. All I can offer is 35+ years of being in and around racing and motorsports of all kinds and hearing feedback form customer who use and don't use certain products.That coupled with the fact that about every professional racing class I can recall seeing uses a relieved rotor of some kind unless they are restricted by rules or there is a size limitation either by rules or wheel size. Recent direct experience would be otherwise stock brake systems on E46 M3's where not only does braking performance feel improved but rotor life is extended as is pad life and fade resistance. But yes,for sure,lets do a whole series of brake component testing because based on the variety of what I see working and not working there is a whole lot of myth and speculation about braking performance,in fact next to oil, it is probably number 1 on the automotive hit parade. So can we use part of your club dues for such a project?
Well, I've got a gun if you'll hold his head still ... You probably also remember when race tires were all treaded tires because ... nobody had devoted enough thought to the idea of using 'slicks' yet. Conventional wisdom that has since been replaced by experience and testing. In competition, I think the real benefit is the extra cooling these disks provide. More cooling = better, more long-lasting brakes. But on the street, they just don't get that hot on a regular basis. There is no doubt that the ultimate physical measure of brakes - total swept area - is actually slightly smaller because, well, holes and grooves don't provide much braking when pressed against pad material. There has been a 'gas relief' theory floated about as a reason to 'relieve' the excess gas buildup but I think anyone who has ever played air hockey knows what a layer of gas would really do to braking. I've actually taught the Gas Laws in chemistry classes. Gas under pressure like that of brake pads against rotors doesn't exist. Well, there's also cold air induction and strut braces for the street ... Hey, it doesn't bother me! I'd love to see some objective tests ... although I suspect some of the parts sponsors might not like the results. D'you remember the 2002 headers tests some 25-30 years ago in Roundel?
Do you mean Jeff Mulchahey's 2002 tii Stahl header evaluation? From what I recall, he saw a minor improvement with the stock tii engine initially, but it was less than he expected, and he had fitment problems. I remember thinking at the time his test metric wasn't the best for repeatability. He came back like a year+ later with an update where he stated something like that he did give original header a fair shake in his first article since he did experience an improvement in flexibility and such, especially at Road Atlanta turn 5 where the exit speed just barely too high for 2nd gear but just a tad too low for 3rd (I remember this since even in my Bavaria it was a 3rd gear pull up that hill, and he said the tii was definitely stronger pulling 3rd up that hill with the Stahl header on it). Anyway, his later article updated the need to match header primary tube diameter with the engine's flow capability, etc. Jeff had significantly modified the head, added a hotter cam, etc, at that time, so new the header was now a much more significant factor. Why do I remember stuff like this? Especially when I sold my Bavaria over 15 years ago now? Heck, I can't even remember what day it is these days! Anyone know what Jeff is up to these days? I've not heard of him in years, but he used to be real active in the Peachtree Chapter.
I don't think so. ISTR this was done at Mid Ohio and they tested 3 or 4 different headers, none of which stood out much from the stock one. As other enthusiasts have also discovered, the apparent biggest impediment to more flow through a BMW head is the BMW head, not the stuff leading into or out of it.
