would a two-piece rotor be a material improvement over stock?

[kolosy]

I cooked my brakes at the track, and need one of everything (well, just rotors and pads). That's $1,500-ish. Or I can get this FS ad https://www.m3post.com/forums/showthread.php?t=1956777 + stock rears for not much more.

Would that make a material heat capacity improvement, or is a kit that size just for looks? I'd like to be able to track it 5-6 times a season, but it's a street car / weekend toy the rest of the time so it needs to be streetable also.

[MP0W3RD]

Originally Posted by kolosy

I cooked my brakes at the track, and need one of everything (well, just rotors and pads). That's $1,500-ish. Or I can get this FS ad https://www.m3post.com/forums/showthread.php?t=1956777 + stock rears for not much more.

Would that make a material heat capacity improvement, or is a kit that size just for looks? I'd like to be able to track it 5-6 times a season, but it's a street car / weekend toy the rest of the time so it needs to be streetable also.

Just purchase OEM rotors from FCP Euro (they are also a two piece design you just can't take it apart) and switch to track pads (either PFC 08s or DS 1.11s)

If you start to cook THAT combination you need to consider much more serious upgrade options.

I have been tracking my car for 4 years and that setup has worked well for me. The free rotor replacement through FCP is one of the best life hacks ever.

[roastbeef]

Originally Posted by kolosy

I cooked my brakes at the track, and need one of everything (well, just rotors and pads). That's $1,500-ish. Or I can get this FS ad https://www.m3post.com/forums/showthread.php?t=1956777 + stock rears for not much more.

Would that make a material heat capacity improvement, or is a kit that size just for looks? I'd like to be able to track it 5-6 times a season, but it's a street car / weekend toy the rest of the time so it needs to be streetable also.

what you posted is an oem replacement rotor and a brembo caliper retrofitted to fit on an oem diameter disk. neither of which are going to help much. this kit is for aesthetics rather than performance. you'll cook these just as fast.

the expensive way is a true bbk.

the more economical way is the cheapest oem rotors from fcp euro (send them back when they're cooked), a good race pad, and castrol srf fluid.

you should also consider how handy you are. are you paying a shop to do this, or can you do it yourself?

[kolosy]

Originally Posted by roastbeef

what you posted is an oem replacement rotor and a brembo caliper retrofitted to fit on an oem diameter disk. neither of which are going to help much. this kit is for aesthetics rather than performance. you'll cook these just as fast.

the expensive way is a true bbk.

the more economical way is the cheapest oem rotors from fcp euro (send them back when they're cooked), a good race pad, and castrol srf fluid.

you should also consider how handy you are. are you paying a shop to do this, or can you do it yourself?

That's helpful, thanks. I'm handy enough -- I generally do my own work unless it requires a thing I don't have (like an alignment rack)

[tdott]

What rotors an pads did you cook? and how old was the brake fluid?

For example, cooking an old set of stock pads and 5 yr old brake fluid isn't saying much. Brakes and esp brake fluid need top be in top shape, otherwise I'd say that is expected.

[kolosy]

Originally Posted by tdott

What rotors an pads did you cook? and how old was the brake fluid?

For example, cooking an old set of stock pads and 5 yr old brake fluid isn't saying much. Brakes and esp brake fluid need top be in top shape, otherwise I'd say that is expected.

stock rotors, mystery pads (but they were fresh and I didn't expect to do much damage given that this was my ... 4th or 5th time at an HPDE and first time in an M3) and a fresh ATE typ200 with a top-off of Castrol SRF when I needed more than the one tin to bleed the system.

[panda-R]

BBK is nice and expensive but seems like a worthwhile investment if you are tracking regularly.

If you're not sure, why not go for the GIRODISC front rotors with some good pads and see how far that takes you?

[kolosy]

what about F80 brakes? looks like i can get into that for about 2400 vs 6k for a full BBK and 1500 for a replacement OEM. Or am I overly fixated on the 380mm rotors?

[roastbeef]

Originally Posted by kolosy

fresh ATE typ200 with a top-off of Castrol SRF when I needed more than the one tin to bleed the system.

do not mix fluids. it doesn't do any good. flush with srf, and srf only. you shouldn't need to top off, but if you bleed the fronts or something, flush with srf. there is no reason to use or flush in anything else.

Originally Posted by kolosy

what about F80 brakes? looks like i can get into that for about 2400 vs 6k for a full BBK and 1500 for a replacement OEM. Or am I overly fixated on the 380mm rotors?

bigger isn't better. my ap kit is 5mm smaller than oem, but its a thousand times better when it comes to consistent stopping power. it comes down to cooling vane count, ventilated pistons, and correct pads. it all works together to keep heat out of the system. you'll see the term "thermal capacity" thrown around a lot, but don't think of it as a way of how much heat it can hold. think of it as how much heat it can get rid of.

your rotors might be ok, you probably have pad deposits from the mystery pads. try a pad like the ferodo ds2500 for starters. its a hybrid pad you can swap at home and drive to the track with. you can daily drive with them too (its what i use for street duty). racing pads will definitely help with standing up to the heat. they are more appropriate for your use, but they'll wear the rotors faster.

here is what i suggest. flush in srf, and try a hybrid pad like the ferodo ds2500 (front and rear). implement a cool down lap in the middle of your session (i'm assuming you're doing a 20 minute session). if you're still cooking brakes, pony up for a bbk.

this is the kit i'd go with. i know you might not be ready, but scroll down and read everything essex does a great job of explaining how/why everything works.
https://www.essexparts.com/ap-racing...93-m3-1m-coupe

[kolosy]

Originally Posted by roastbeef

do not mix fluids. it doesn't do any good. flush with srf, and srf only. you shouldn't need to top off, but if you bleed the fronts or something, flush with srf. there is no reason to use or flush in anything else.



bigger isn't better. my ap kit is 5mm smaller than oem, but its a thousand times better when it comes to consistent stopping power. it comes down to cooling vane count, ventilated pistons, and correct pads. it all works together to keep heat out of the system. you'll see the term "thermal capacity" thrown around a lot, but don't think of it as a way of how much heat it can hold. think of it as how much heat it can get rid of.

your rotors might be ok, you probably have pad deposits from the mystery pads. try a pad like the ferodo ds2500 for starters. its a hybrid pad you can swap at home and drive to the track with. you can daily drive with them too (its what i use for street duty). racing pads will definitely help with standing up to the heat. they are more appropriate for your use, but they'll wear the rotors faster.

here is what i suggest. flush in srf, and try a hybrid pad like the ferodo ds2500 (front and rear). implement a cool down lap in the middle of your session (i'm assuming you're doing a 20 minute session). if you're still cooking brakes, pony up for a bbk.

this is the kit i'd go with. i know you might not be ready, but scroll down and read everything essex does a great job of explaining how/why everything works.
https://www.essexparts.com/ap-racing...93-m3-1m-coupe

thank you! super helpful.

fwiw, i mixed fluids because i ran out of the typ200, and still had bubbles coming out so i needed something to top up. don't ask my why i didn't start with the srf -- i don't have a good answer ¯\_(ツ)_/¯

rotors have a rainbow on them and pretty substantial grooves. you think still salvageable?

[roastbeef]

Originally Posted by kolosy

thank you! super helpful.

fwiw, i mixed fluids because i ran out of the typ200, and still had bubbles coming out so i needed something to top up. don't ask my why i didn't start with the srf -- i don't have a good answer ¯\_(ツ)_/¯

rotors have a rainbow on them and pretty substantial grooves. you think still salvageable?

rotors sound shot, but put up a couple pics.

where were the bubbles? i wouldn't top off and mix with a lesser fluid, you're basically compromising the srf and wasting it.

[kolosy]

Originally Posted by roastbeef

rotors sound shot, but put up a couple pics.

where were the bubbles? i wouldn't top off and mix with a lesser fluid, you're basically compromising the srf and wasting it.

i'll snap some tomorrow.

bubbles were as i was bleeding the system. i knew i needed fresh fluid (no record of PO doing it), and had a set of SS lines that I figured I'd put on as well, so there was a decent amount of flushing.