[IraHayes]

I’m not usually one to mod my car unless it enhances reliability, or safety. In this case, I’d like to improve the breaking performance of my car. I want to go with cross drilled and slotted rotors, but am somewhat irritated that there isn’t an OEM option for non-M or non-M sport package cars. This has me looking into aftermarket options. Mainly, these:

https://www.ecstuning.com/b-ecs-part...74875xsgmtlra/

https://www.ecstuning.com/b-stoptech...16855006cdsl~/

https://www.cquence.net/partfinder/p...328i&year=2015

Anyone have experience with these brands, or any others for that matter?
How about pads? Stick with OEM, or go with something like Hawks?

[Billfitz]

Unless you're on the track cross drilling and slotting doesn't improve braking. If anything it makes it worse. Maximum braking comes from maximum contact area between the pads and rotors. Drilling and slotting reduces the swept area of the rotors. That's an acceptable compromise on the track, where reducing heat build up via the added ventilation to minimize fade is more important than pure grab.

[IraHayes]

Originally Posted by Billfitz

Unless you're on the track cross drilling and slotting doesn't improve braking. If anything it makes it worse. Maximum braking comes from maximum contact area between the pads and rotors. Drilling and slotting reduces the swept area of the rotors. That's an acceptable compromise on the track, where reducing heat build up via the added ventilation to minimize fade is more important than pure grab.

You know, it’s interesting that you say that. The M rotors are larger in diameter, probably, partially for that very reason, to add back surface area taken away by the holes. I’ve been doing a little more research on the subject. Back when I worked on cars for a living, we were taught about the affects of “gas gap” between the pads and the rotor that will cause brake fade, especially under hard/emergency braking, or when the brakes start getting hot. From what I’m learning, this was little more than a myth, as gasses generated were minuscule at best. Even if somewhat true, the materials used in modern pads pretty much eliminated the problem years ago. I suppose it still might be possible if you go with some cheap quality “budget gourmet” brake pads. I’ve also come to find out that in racing applications, vented rotors are the most commonly used, followed by slotted, with cross drilled being rarely if ever used at all anymore, for reasons you stated, worse performance basically. Looks like the most common reason why cross drilled rotors are used on modern cars at all is because they simply look cool. They do, and if you ask the ricers, they add about 50 hp.

I will be spending the money I would have spent on an unnecessary “upgrade” on extra oil, filters, and some tools. Also a couple of Blackstone analyses. I’m running Pennzoil pure plus platinum euro 5W-40 in my car right now. Will be dumping it in about 1000 miles and refilling with Liqui Moly Molygen 5w-40. I will send that oil in for analysis as well so that I can compare. Might try Motul as well, we’ll see.

[Billfitz]

If you want to see what works look at a cop car. They need to go 60-0 as quick as 0-60. I noticed a cop Ford SUV, don't ask me which one, which for whatever reason had aluminum spoke wheels instead of the usual steel, so I could see the rotors. They were massive, and they weren't slotted or drilled.

[cfm56d7b]

@IraHayes, what is your budget for brakes upgrades?

If your car already has M Sport brakes, these brakes already offer excellent braking performance for the price. M Performance aftermarket brakes are identical with the exception of dimpled / slotted rotors offering little extra braking performance in daily driving conditions. Dimpled rotors can contribute to extra noise, while annoying entirely normal.

The next increment in braking performance costs more: about $3K (and higher) per axle offering larger rotors, 6 piston calipers in the front, 4 piston calipers in the rear. The common choices are Stoptech, Brembo, and AP Racing.

Pads make a huge difference. For daily driving, pad offering aggressive initial bite is perhaps the best choice while producing more brake dust.

[IraHayes]

Originally Posted by cfm56d7b

@IraHayes, what is your budget for brakes upgrades?

If your car already has M Sport brakes, these brakes already offer excellent braking performance for the price. M Performance aftermarket brakes are identical with the exception of dimpled / slotted rotors offering little extra braking performance in daily driving conditions. Dimpled rotors can contribute to extra noise, while annoying entirely normal.

The next increment in braking performance costs more: about $3K (and higher) per axle offering larger rotors, 6 piston calipers in the front, 4 piston calipers in the rear. The common choices are Stoptech, Brembo, and AP Racing.

Pads make a huge difference. For daily driving, pad offering aggressive initial bite is perhaps the best choice while producing more brake dust.

No, my car is a only a lowly 328i. I wanted to upgrade to drilled and slotted rotors because I mistakenly believed they improve braking performance. It's actually an increase in surface area of the pad and rotor that improves this. For me to reap that benefit, I would have to, as you point out, upgrade to "M" spec brakes. That's an expense I wanted to avoid. I don't really flog my cars to death, so the OEM set-up will do. I will however likely look into different pads as I know different materials can make a big difference. First I need to look into what material the OEM pads are so that I don't mistakenly downgrade.

[cfm56d7b]

Originally Posted by IraHayes

No, my car is a only a lowly 328i. I wanted to upgrade to drilled and slotted rotors because I mistakenly believed they improve braking performance. It's actually an increase in surface area of the pad and rotor that improves this. For me to reap that benefit, I would have to, as you point out, upgrade to "M" spec brakes. That's an expense I wanted to avoid. I don't really flog my cars to death, so the OEM set-up will do. I will however likely look into different pads as I know different materials can make a big difference. First I need to look into what material the OEM pads are so that I don't mistakenly downgrade.

Great article to read - please see below. Different brakes pads are also discussed.

https://www.turnermotorsport.com/t-b...ke-Differences

[IraHayes]

Originally Posted by cfm56d7b

Great article to read - please see below. Different brakes pads are also discussed.

https://www.turnermotorsport.com/t-b...ke-Differences

Thanks for that link! I will probably go with the M Sport pads. They are an OEM part, and that's my preference. Thanks again!

[cfm56d7b]

Originally Posted by IraHayes

Thanks for that link! I will probably go with the M Sport pads. They are an OEM part, and that's my preference. Thanks again!

Glad to help. Please update this thread after trying new pads. Will surely help another forum member.

[Billfitz]

Originally Posted by IraHayes

Thanks for that link! I will probably go with the M Sport pads.

Be sure they'll fit your calipers. With the 328 they may not.

[Solidjake]

Get Hawk HPS 5.0 pads and Zimmerman rotors.