E89 Z4 4-corner big brake upgrade with Brembo m-sport calipers
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Just wait until we get all of this done and then it doesn't work. The suspense is deafening!
Filippo
BESPOKE CALIPER BRACKET ADAPTERS:
We finished TIG welding up the brackets yesterday. It's gotten hard to get prototype stuff plated these days, so chasing a few options down. I have a reference to a plater and am waiting to hear back. I've been doing some etchant and type 2 anodizing work on 7075 on aluminum, so I'm also contemplating a plating solution for 3DM, since low volume parts are frequently made and a there is a need to corrosion protect them.
So the brackets were initially mocked up in wood. We went to setting everything up in the shop for final measurements, CAD drawings, and some initial prints of the CAD drawings to verify bolt hole distances.
The bracket runs along the rear of the hub mounting tabs. To mount to the caliper bracket, two spacers are needed to cover the distance between the bracket plate and caliper bracket. The spacers are 1 1/8" OD with the same M12 internal sizing for the bolts. These days @barry@3DM no longer really mills basic 2D parts in the shop - it's much more effective to upload CAD drawings to sendcutsend.com and just have them laser cut the parts and expedite to us. Parts are typically batched up for cost and arrive a few days after placing the order. So we spec'd 1/2" mild steel (overkill for sure but no FE analysis here) for several sets of brackets. The brackets arrived a few days later. We underspec'd the internal hole size so we could final drill and ream the bracket holes to accurate dimensions.
We then ordered up some 1 1/8" mild steel rod from McMaster so we could turn the spacers on the lathe and fit them. As a small detail - we didn't want to have the spacers pre-cut as we'd rather bolt the bracket plate and do final spacing fitment on the spacers since the brackets have tight clearance tolerance on both sides of the rotor. Once we determined spacer thickness, they were all turned to the same depth, pilot hole centered, drilled, reamed, then chamfered for TIG welding to the bracket.
With everything fabricated, Barry TIG welded the spacers in place, and then we validated final fitment.
Now brackets will get final metal clean up, receive finishing, and await complete suspension and brake installation.
Filippo
We finished TIG welding up the brackets yesterday. It's gotten hard to get prototype stuff plated these days, so chasing a few options down. I have a reference to a plater and am waiting to hear back. I've been doing some etchant and type 2 anodizing work on 7075 on aluminum, so I'm also contemplating a plating solution for 3DM, since low volume parts are frequently made and a there is a need to corrosion protect them.
So the brackets were initially mocked up in wood. We went to setting everything up in the shop for final measurements, CAD drawings, and some initial prints of the CAD drawings to verify bolt hole distances.
The bracket runs along the rear of the hub mounting tabs. To mount to the caliper bracket, two spacers are needed to cover the distance between the bracket plate and caliper bracket. The spacers are 1 1/8" OD with the same M12 internal sizing for the bolts. These days @barry@3DM no longer really mills basic 2D parts in the shop - it's much more effective to upload CAD drawings to sendcutsend.com and just have them laser cut the parts and expedite to us. Parts are typically batched up for cost and arrive a few days after placing the order. So we spec'd 1/2" mild steel (overkill for sure but no FE analysis here) for several sets of brackets. The brackets arrived a few days later. We underspec'd the internal hole size so we could final drill and ream the bracket holes to accurate dimensions.
We then ordered up some 1 1/8" mild steel rod from McMaster so we could turn the spacers on the lathe and fit them. As a small detail - we didn't want to have the spacers pre-cut as we'd rather bolt the bracket plate and do final spacing fitment on the spacers since the brackets have tight clearance tolerance on both sides of the rotor. Once we determined spacer thickness, they were all turned to the same depth, pilot hole centered, drilled, reamed, then chamfered for TIG welding to the bracket.
With everything fabricated, Barry TIG welded the spacers in place, and then we validated final fitment.
Now brackets will get final metal clean up, receive finishing, and await complete suspension and brake installation.
Filippo
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You guys logging your time on this endeavor? Wondering what those "simple" brackets would end up costing retail...
The R&D for some custom solutions truly is a labor of love (or stupidity)
The R&D for some custom solutions truly is a labor of love (or stupidity)
We plan to provide CAD drawings for bracket materials. One can order from sendcutsend. Can be installed without welding spacer - sandwich works just fine. Will release CAD drawings once we know it works. We're not in the brake market, and Z4 ... hard to call that a market lol. It still requires helicoil tapping the rear tabs and turning down rotors to fit, which any shop with a brake lathe can do. Also there is a version of that rear caliper assembly far more common in the USA, that is black powder coated.
Filippo
Filippo
Or dense and persistent. Could be the same thing!
I just wanted to retain the emergency brake and have it look like a factory setup.
Filippo
Progress has been slow on the brakes, mostly because it is moving in parallel with several other projects. I've been building several EKPM3 active cooling LPFP's (DIY thread coming eventually), a BMW Reprogramming Charger (which is nearly complete), and the long pole in the tent is a pretty extensive suspension with lots of bespoke parts and includes a full Ćhlins TTX setup.
On the brackets, it is getting hard to find people that do small-batch plating. So I decided to do my own zinc yellow chromate plating. There is plenty about this on Youtube or forums. It was a pain in the butt (much easier to do small parts (like nuts and bolts and hanger brackets), but I digress. Here is a photo of the finished bracket. Digging into the BMW parts bin, I got close on mounting hardware. For the bracket to trailing arm, 33406787466 which are M12x1.5-33mm torx. For the bracket to caliper, 34116778234 which are M12x1.5-43mm. (a small digression on 34116778234 - it is listed 43mm but includes a 3mm integrated washer. One would think that the 43mm measurement would be derived from the base of the washer since it is integrated, to the tip of the fastener. Nope. So it is actually 40mm which is a bit shy of what I would have ideally liked.)
Filippo
On the brackets, it is getting hard to find people that do small-batch plating. So I decided to do my own zinc yellow chromate plating. There is plenty about this on Youtube or forums. It was a pain in the butt (much easier to do small parts (like nuts and bolts and hanger brackets), but I digress. Here is a photo of the finished bracket. Digging into the BMW parts bin, I got close on mounting hardware. For the bracket to trailing arm, 33406787466 which are M12x1.5-33mm torx. For the bracket to caliper, 34116778234 which are M12x1.5-43mm. (a small digression on 34116778234 - it is listed 43mm but includes a 3mm integrated washer. One would think that the 43mm measurement would be derived from the base of the washer since it is integrated, to the tip of the fastener. Nope. So it is actually 40mm which is a bit shy of what I would have ideally liked.)
Filippo
I'm going to front run the suspension thread a bit. This is the F30 S2HNA / F80 M3-M4 Brembo front calipers (370/380 mm) with 2-piece Zimmerman 370mm F30 S2HNA front rotors. This is sitting on an E89 hub mounted to an F30 front spindle. Ignore the suspension stuff for now
Filippo
Filippo
Ignore the suspension stuff for now
Filippo
How on earth are we supposed to do that? JUST LOOK AT IT!
Btw any pics of how the rear upper control arms turned out? Or are you converting to a regular arm given the rear coilover?
You will love the bearing rtab btw. Please consider solid rear subframe bushings as well.
Anyhow, this path of upgrading to bbk, looking atvwhat you are going through, if anything it tells me buying a complete kit from for instance PB is worth the premium?
It is actually the same on stock Z4s, or at least mine was (EUR version). The floating rotors I use now don't save any significant weight in comparison to stock. It's the calipers that offer the most weight saving potential.
Yeah I know. Firing up the suspension thread will take a bit of effort and I'm not quite ready on that. There was really no way to show the front brake stuff without what it is hanging on lol ...
They are finished. The whole suspension is finished. We're just waiting on a couple small parts that we missed for the rear. It will all get posted up shortly.
That's good to hear. Barry has other ideas on the rear subframe but there are too many balls in the air to deal with that right now.
Good observation. Generally I would say yes. BUT with caveats. First, I had to go figure all this out. I've seen no one on any BMW platform do an EMF-based upgrade. So the work is not as consuming as my having to go spelunking
. I wanted a factory appearance brake setup, so that was a factor which is probably not most people's concern.We have the CAD drawing for the bracket, which someone can use to reasonably produce one-off bracket set (i.e.; send cut send, a drill press, and a welder - if one took the 2D cut plates to a machine shop they could cut the round steel spacer, weld, and drill the spacer out. The spacers don't even need to be welded, but anyone capable of cutting and facing steel from round tube will be able to weld it). Heli-coil for the rear trailing arm is straightforward. Honestly the issue is clearance between the rotor and caliper bracket. We clearanced the bracket on the mill, since we have a mill, and it was a more elegant solution. The other way I considered was turning down the E46 M3 CSL rear rotors (many shops have equipment to turn rotors). This would provide clearance. It would take that rotor to minimum thickness spec, but it is the rear rotor on a Z4 and massive - I suspect that's not an issue.
Generally speaking $2,400USD and shipping gets the rear setup from PB Brakes, which from what I know is good and known to work (good rep, made in Taiwan). Unfortunately this EMF stuff has not been breached as product by the aftermarket. PB's solution is $750USD and they won't sell it without the kit, so it's all or nothing.
And remember - we still don't know how my setup works. Everything on paper says it does. On paper
...Filippo
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That suspension looks great, lets see more of that and screw up your brake thread.
Ok ... no ... I was missing something! In all the heat in the garage, amid all the work, I missed this completely. FCP sent me the wrong rotors - Zimmermann makes both the 1-piece and 2-piece. I wrote them this evening to get them to send the correct ones. Thanks for catching it. Both are coated the same so not as obvious as the rotors where the aluminum is left bare. I missed the rivets ... never noticed they were not there lol.
Filippo
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