[justpete]

Originally Posted by Dan Bilzerian

Are the csl rotors hard to come by? You can only resurface them for so long until they're shit. I'm eagerly awaiting pictures of the backing plate!

Orderable as any other BMW part. No plans to resurface any rotors so not an issue. Won't get much wear since they're rear brakes so even replacing them should be a no-worry issue, too. Will post everything I can to help others do the same thing if they want.

[Yury]

Originally Posted by justpete

Um, forging will make a part stronger but it in no way can make a part lighter, per se. Your rims going through that press means nothing, sorry.

Us engineers tend to make things that work rather than halfassing stuff into existence. Those who don't know what they don't know often confuse this with "complicated".

The final solution has already been explained as using the e46 M3 CSL rear rotors with 135i rear calipers. Nothing needs to be modified except the parking brake backing plate which the shop knows how to modify to use the e46 M3 183mm diameter parking brake shoes.

Thus the solution for the rear brakes is "engineered" by BMW, discounting the parking brake since it's only needed to pass safety inspection to keep it street legal.

Those who think they know often confuse the knowledge and "opinion".
I was asking for pictures not your explanations, sorry to "confuse" you.

[andrey_gta]

Looking forward to any progress information.

[justpete]

Originally Posted by andrey_gta

Looking forward to any progress information.

Yeah, me too. Shop ordered parts, some had to come from Germany. And the work cutting and welding ducts into the body behind the now opened up Aero rocker cover vents has taken some planning so the caliper cooling hoses can be sure to fit. Pretty sure the car's off to the cage shop and then back through the paint shop after that. They'll likely be doing the rear brake custom work after that. First race is the first weekend of March so not much time left.

[sirantsE90]

Originally Posted by justpete

Orderable as any other BMW part. No plans to resurface any rotors so not an issue. Won't get much wear since they're rear brakes so even replacing them should be a no-worry issue, too. Will post everything I can to help others do the same thing if they want.

Did you see ECS is now selling kits with the E46 csl rotors.

[justpete]

Originally Posted by sirantsE90

Did you see ECS is now selling kits with the E46 csl rotors.

That's for the front and I'm pretty sure those are ECS's rotors rather than BMW M3 CSL rotors.

[tom.gnade]

So how did this turn out? What needed to be done to make it work?

[STR8-6IX]

Im pretty sure the 135 and 335i share the same brake components.

whats the point of upgrading rear brakes if its the fronts that do most of the work?

if you are looking for better pedal feel, steel brake lines are a good option.

[justpete]

Originally Posted by 6IX-F10-N52

Im pretty sure the 135 and 335i share the same brake components.

whats the point of upgrading rear brakes if its the fronts that do most of the work?

if you are looking for better pedal feel, steel brake lines are a good option.

135i and 335i brakes are totally different with no parts in common.

Rear brake upgrade makes sense when alteration to the front mandates a change to the rear to maintain bias.

Stainless lines don't do a thing for brake feel. Never have, never will. Their sole purpose is to be robust in the high temp, high vibration environment of a race car.

[justpete]

Originally Posted by tom.gnade

So how did this turn out? What needed to be done to make it work?

You mean the e46 M3 CSL rear rotors with 135i calipers? Just needed a 5mm axial spacer to shift the caliper to center up on the rotor. Otherwise worked perfectly. Noisy as all hell though, that rotor really sings.

[Terraphantm]

Originally Posted by justpete

You mean the e46 M3 CSL rear rotors with 135i calipers? Just needed a 5mm axial spacer to shift the caliper to center up on the rotor. Otherwise worked perfectly. Noisy as all hell though, that rotor really sings.

Get the Euro E39 M5 rear rotors (34212228801 / 34212228802). Not drilled, but they've still got the aluminum hubs like the CSL / ZCP / Euro M3 rear rotors. Dimensions are identical otherwise.



Alternatively you can get the US-spec M5/M3 rear rotors. Also not drilled, but steel hub / non floating design.

[justpete]

Originally Posted by Terraphantm

Get the E39 M5 rear rotors. Not drilled, but they've still got the aluminum hubs like the CSL / Euro M3 rear rotors. Dimensions are identical otherwise.

Nice! Many thanks! This will make things vastly less annoying. Very cool.

[justpete]

Originally Posted by Terraphantm

Get the Euro E39 M5 rear rotors (34212228801 / 34212228802). Not drilled, but they've still got the aluminum hubs like the CSL / ZCP / Euro M3 rear rotors. Dimensions are identical otherwise.



Alternatively you can get the US-spec M5/M3 rear rotors. Also not drilled, but steel hub / non floating design.

Oh! Those aren't floating rotors like the CSL parts, bummer. Gotta have the floating two piece rotors so guess I'm stuck with the noise. Bummer.

Wait, are those radial pins like the CSL rotors making them floating after all?

[Terraphantm]

Originally Posted by justpete

Oh! Those aren't floating rotors like the CSL parts, bummer. Gotta have the floating two piece rotors so guess I'm stuck with the noise. Bummer.

...They are. Look at them.



It's the same casting. Just drilled afterwards.

[justpete]

Originally Posted by Terraphantm

...They are. Look at them.

Hard to see on this computer but pretty sure that's what I'm seeing, good news, thanks again!

[justpete]

FWIW, the local race shop is talking with Tilton Engineering about a Series 600 underfoot pedal box. Would be able to dial in front/rear bias while driving and it gets rid of the rest of the crap in the stock braking/stability system including wheel speed sensors, etc. Still not sure how the rest of the car would react to the ABS/DSC system being totally physically removed though. At least it's not a terribly expensive mod.

[Terraphantm]

Well you'd lose your speedometer and odometer for one thing since that's taken from the ABS sensors

[justpete]

Originally Posted by Terraphantm

Well you'd lose your speedometer and odometer for one thing since that's taken from the ABS sensors

Yeah, at that point the dash would be disconnected and replaced with a Motec or Race Technology street legal dash. Of course it'd use one wheel speed sensor or an equivalent.

[tom.gnade]

Originally Posted by Terraphantm

Get the Euro E39 M5 rear rotors (34212228801 / 34212228802). Not drilled, but they've still got the aluminum hubs like the CSL / ZCP / Euro M3 rear rotors. Dimensions are identical otherwise.



Alternatively you can get the US-spec M5/M3 rear rotors. Also not drilled, but steel hub / non floating design.

You think those M5 front rotors would work with the F30 calipers? We know those calipers can handle the 348x30mm stock E92 335i rotors, and they work fine on 340x30mm F30 rotors, so the 345x32mm M5 rotor diameter is fine, but would the 32mm thickness be a problem? I wonder if they would even fit on the E92 front hubs as a bolt-on.

[tom.gnade]

The E34 M5 also had front and rear floating rotors with the same dimensions, though I have no idea if it uses the same offsets. The rear rotors look like they weigh a touch more than the E39 M5 set, so no advantage to using them, but the front rotors only weigh 9.1kg according to this:

http://www.realoem.com/bmw/enUS/part...&q=34112227735

http://www.pelicanparts.com/cgi-bin/...on=34112227735

Pelican shows them at 19.97lb, which is about 9.1kg - the only thing better than that that I've found is the E46 M3 competition package front rotors, which are 345x28 and only weigh 7.6kg. Unfortunately, it looks like they would need brackets to fit, or I would just put those rotors on front and rear and call it a day.

[tom.gnade]

a bit off-topic, pardon.

[tom.gnade]

Could a 335i 336x22mm rear rotor be used with the rear 135i caliper (with the welded e-brake mod)? We know the caliper can handle a 330x20mm F10 rotor, so would 336x22mm or 24mm be too much? The 335i rotor fits the 328 hub and upgrade options are much more common.