[noname1]

Looking to get some upgraded brakes for my e92 335i. Current zimmerman discs w yellow stuff pads have warped and wasn't particularly impressed even before that. Has anyone any experience with the 370mm m3/m4 brakes, I know they're a popular upgrade but does anyone have any first hand experience on what sort of improvement I could expect? Also if anyone has any big brake kits for sale I could be interested. Cheers

[OliSharp]

what sort of driving are you doing to warp the discs? maybe have a look at some brake ducts to improve cooling as well?

The blue F series Brembos work well: skip 5:45

[therealdb1]

Just come to a big stop and sit there with your foot on the brakes often does the trick.
Gives an excuse to change discs and pads I guess!

[noname1]

Originally Posted by OliSharp

what sort of driving are you doing to warp the discs? maybe have a look at some brake ducts to improve cooling as well?

The blue F series Brembos work well: skip 5:45

No track driving just fast road, I live on some nice B roads so it does get driven pretty hard but still disappointed they've warped. Had the same on my previous car too. Will look into brake ducts that could be a good idea

[noname1]

Originally Posted by therealdb1

Just come to a big stop and sit there with your foot on the brakes often does the trick.
Gives an excuse to change discs and pads I guess!

They're only 6 months old so it pains to buy another set - have tried the coming to a quick stop but didn't improve it unfortunately. I'll go with the m4 brakes when I can bring myself to part with the money - some new MTEC discs should do for now

[therealdb1]

"Just come to a big stop and sit there with your foot on the brakes often does the trick."

I meant that's what can cause warping not that it fixes it!

[AD18]

Originally Posted by noname1

No track driving just fast road, I live on some nice B roads so it does get driven pretty hard but still disappointed they've warped. Had the same on my previous car too. Will look into brake ducts that could be a good idea

I'm surprised you've managed to warp them with road driving, you really must have been moving! The only time I've managed it was when I took mine on track and they never used to last very long at all. I also had yellow stuff (and zimmerman at the time) but was never really impressed, they lasted all of about 2 laps. I tried PFC after and they were much better but not perfect.
The spending was getting out of control at this point, throwing all different pads/discs at it but could never get something solid enough to take the abuse, BBK was too much for me at the time so abandoned all track driving in the end.

However, I would say that if it's judder that you're getting which is making you think you have warped discs I would suggest trying a more stout pad first. Reason being that after the track sessions I did plenty of road driving after and it all cleared away. I believe it was a lot of pad material that was sort of being embedded onto the disc face unevenly with the extreme heat which was causing it, I assume after normal driving it eventually "scraped" off and all returned to normal. I also had said discs checked and there was no evidence of play. Just my experience anyway, I definitely feel the frustration though.

[OliSharp]

Doubling up on the comments above here slightly: are you sure the discs are actually warped (have you checked them with a dial gauge)? You could also remove them and place on a flat surface to check for warping.

Could well be pad deposits on the disc (also mentioned above) which, under light braking, feels like the discs are warped. If this is the case you can either abrade the disc with a scotchbrite pad / light sand paper, or do some heavy braking (but keep driving afterwards so the discs can cool properly) to remove the pad deposits.

If you've been really leaning on the anchors then stop moving (at a junction or traffic lights), this can lead to warped discs (as mentioned above) or pad deposits on the disc. Lots of town driving can cause pad deposits too. Worth checking before you buy new discs.

If you do need new discs, I got my front OEM from the stealership, and rear ATE from ECP with a discount code. I can recommend both. Mine have done several Brecon Beacon excursions with no issues.

Pads: PFC Z-rated (mentioned above) or Paid RSL29, are good ‘performance’ pads (along with braided lines and high temp fluid). Endless also very good but likely overkill for the road.

Upgrading to the blue Brembo calipers won't necessarily solve your disc warping issue, as they'll still generate a lot of heat.

I have no experience with MTec discs I'm afraid so can’t comment on how good they’d be.

Not finishing your drive / stopping with hot discs is the key. A bit of a cool down (cruising around off boost) will prolong your turbos lives too (ensuring high oil flow relative to turbine speed before you switch the engine off).

[Smokey33]

Mtec are shit imo.

[noname1]

Originally Posted by OliSharp

Doubling up on the comments above here slightly: are you sure the discs are actually warped (have you checked them with a dial gauge)? You could also remove them and place on a flat surface to check for warping.

Could well be pad deposits on the disc (also mentioned above) which, under light braking, feels like the discs are warped. If this is the case you can either abrade the disc with a scotchbrite pad / light sand paper, or do some heavy braking (but keep driving afterwards so the discs can cool properly) to remove the pad deposits.

If you've been really leaning on the anchors then stop moving (at a junction or traffic lights), this can lead to warped discs (as mentioned above) or pad deposits on the disc. Lots of town driving can cause pad deposits too. Worth checking before you buy new discs.

If you do need new discs, I got my front OEM from the stealership, and rear ATE from ECP with a discount code. I can recommend both. Mine have done several Brecon Beacon excursions with no issues.

Pads: PFC Z-rated (mentioned above) or Paid RSL29, are good 'performance' pads (along with braided lines and high temp fluid). Endless also very good but likely overkill for the road.

Upgrading to the blue Brembo calipers won't necessarily solve your disc warping issue, as they'll still generate a lot of heat.

I have no experience with MTec discs I'm afraid so can't comment on how good they'd be.

Not finishing your drive / stopping with hot discs is the key. A bit of a cool down (cruising around off boost) will prolong your turbos lives too (ensuring high oil flow relative to turbine speed before you switch the engine off).

Have since bought a far superior DTI gauge and the discs seem to be okay ( only 1 mm variance around circumference compared to 5/6mm on the old gauge ). Have since removed all wheels and thoroughly cleaned the discs and around the callipers with compressed air. Have also had the car aligned at a proper specialist. Symptoms have significantly improved, almost no judder. I'm still not completely happy with the feel under hard braking however knowing what I now know, I am thinking the car could benefit from new m3 arms and some new bushes which was next on the list anyway. Thanks all for your input.

Also worth adding I have a ridiculous level of mechanical sympathy. It gets warmed up religiously before I even consider hitting boost and I spend at-least the final 10 minutes driving like an absolute granny to ensure all the fluids have an opportunity to cool down.