Black & Tan 332iT

[Bry5on]

I was a little under the weather this weekend, so I decided that a nice leisurely activity would be to swing by the junk yard to look for auto dimming e90 sport mirrors for my M3 mirrors which will go on some day. Well, I found some, and also managed to find a bunch of little things that all made small improvements.

The auto-dimming mirror glass (I brought a battery and tested them both) that I paid a whopping $5 for, fitted into M3 mirrors:


The late e46 insulated foot well cover that replaced my cracking non-insulated one:


A late e46 HVAC control panel, cleaned thoroughly before installing:



And last, a driver's seat memory module, harness and motor. Lately I've been letting a few people drive my car and I was reminded that 1) the rocker switch is a little hard to find on the seat side and 2) I like having seat and mirror memory. At basically no cost or weight penalty, I tore this thing down, removed the seat tilt button, de-pinned and de-wired all of the no longer useful wiring and pins, then adhered the memory module to the side of the recaro seat base with double sided tape. Memory seats are nice to have again!

[Bry5on]

Now I've done the math and given this a bit more thought. Flexures have been thinned out a bit to .008", I'll be using 301 tempered stainless spring steel and can get away with anywhere between 4-8 flexures and still outperform the adjacent aluminum parts. That said, I still want a safety net for a part like this in the steering system, so three positions will get keepers in place of washers, clocked 90 degrees apart, which will keep the steering functional even in the event of catastrophic failure of all of the springs. Overall, it's over constrained, so we'll have to see how this works in practice. First four springs hidden for clarity:

[Bry5on]

Alright, the parts for v2 of the solid steering coupler are on order. This time using 7 or 8 .030" 304 stainless steel flexures to replace the rubber bushing.

My first go at this using spherical bearings didn't end up to my liking once I'd finally assembled it all, and I like this solution better anyway. This one is simpler, cheaper and has no wear parts.

[Bry5on]

Two different welders came out today to knock out the last of the jobs that I was really not looking forward to. This am, I swung by Kevin’s place and had a friend who’s good with a torch weld in v-brace mounts for the OEM M3 underbody brace. This gave a nice increase in stiffness, but more noticeably removed a little post-bump vibration from the rear end. The rear is caught up with the front now



After a burrito, I decided to tackle the M3 header/AC line heat shield that’s on all M3s. This part is skipped on every single swap I’ve ever seen, and we’re not having that. Using factory BMW coarse thread studs, we successfully stud welded the missing three frame rail studs to attach that last missing heat shield, and I can rest easy. Since I had to evacuate the AC system to remove the lines for stud welder clearance, I took the opportunity to recharge the AC (evacuation reported it was only 70% full, missing 200 grams of R134).

[YoitsTmac]

I didn't know we had so many in the bay. September 9th we have a cars and coffee at BMW San Rafael. I'd love to see some amazing rides. Alternatively, we can set something more formal up as well

[maupineda]

Meet up mext weekend?

Suggesting next weekend cause mine won't be done until then

If you take another visitor, I will love to join

[heinzboehmer]

Meet up mext weekend?

Suggesting next weekend cause mine won't be done until then

[YoitsTmac]

Looks awesome! I sent you a PM. I'm in Marin and I'd love to see this build!

[Bry5on]

Rears went in just fine. Feels great!

[Bry5on]

Front brakes went in and got bedded tonight. Rears will have to follow this weekend.

So far I’m pleased with the more immediate and confident pedal. The dead zone before pad bite is definitely reduced, and there’s less weird feedback on long downhill braking. Looking forward to doing the rears now.

The scales had these at exactly one pound less per front corner than the 325mm euro setup I had before. Not a bad tradeoff, although I swear I could feel the change in inertia from the bigger rotors. Probably just placebo..

[Bry5on]

Calipers arrived last night, so I swung in to the machine shop this morning for an hour to knock out the 5.5mm machining needed to make these fit the 345mm ZCP rotors. These calipers are nearly perfect, really pleased with the paint and seal condition! Looks like the pads in the rear calipers were still the ones from the factory! Fronts were replaced textars

[Bry5on]

It’s been a little bit.. now that it’s summer and warm I’m chasing overheating again. In pursuit of solving that, I swapped the M3 aux fan and radiator ducting in. An improvement, but no dice. The car still overheats on hot days uphill with AC on, even at highway speeds. Maybe another radiator is in the cards, as I’ve been through three thermostats, two thermostat housings, two water pumps and two radiators. Really strange, super repeatable and temps are actually going up, it’s not just the gauge. I’ll get it eventually.




I also made and added some 6mm spacers to the stock M3 springs to bring it more to ZHP height. The roads around me really are shit and this made a great difference.



And last, I swung over to mrgizmo04’s place to test fit my wheels over 996 brakes, as by the measurements it was going to be super close and I didn’t want to commit if it was going to require a large spacer. Well, it was super close, just over 1mm of clearance to the 345mm brakes and 996 calipers over the 17x9 et47 wheels. I ordered some 6mm spacers to make it 2.5mm and placed orders for black Porsche calipers and all the parts needed for the brake conversion. I miss that Porsche pedal feel and one ride sold me on the swap. That, and the fact that my wife’s SUV and my 50 year old stock-brake sedan have better pedal feel than my M3 setup..



Other than that, just putting the miles on. It’s doing great.

[Bry5on]

Math worked out once again. Perfect fitment of the 17x9 et52 e82 1 series wheels after adding some spacers. I’m not a fan of spacers, but there really wasn’t another option that fit the requirements. These end up being 7lb lighter per corner, dropping almost 30lb.

In front, with a 245/40/17 on a 17x9 et47 (after 5mm spacer) wheel, there’s 3.5mm clearance to the strut and just a few millimeters of tire past the fender with 2.15 degrees of camber from flipped strut hats set full positive. We’ve successfully preserved the correct factory scrub radius and steering feel.

Measurements are coming out at around 3mm clearance to 996 calipers, although I’m going to need to test fit this on another car before I commit to changing the brakes.

In the rear, I’m running the same 245/40/17 on the same 17x9 (can rotate these) but with a 12mm spacer and 1.6 degrees of camber. This puts the tire lip straight under the fender, and it also appears to clear with no spacer. I still have to pull the spring out and check full travel clearance to validate, but it looks promising given the tire stretch.

All told, happy with how all this is turning out, even though I’m giving up my favorite factory wheels.

[Slideways]

I committed yesterday and picked up a set of them. Overall they’re still light and ultimately I think this is the best balance of the above priorities. Bonus points that they’re the most affordable.

Also, it might be easier to get replacements or extras if you need them rather than the discontinued wheel.

[Bry5on]

The only 17 ET52 option that only has 7 in stock is the flow formed wheel - https://www.apexraceparts.com/store/...bmw-wheel.html

I committed yesterday and picked up a set of them. Overall they’re still light and ultimately I think this is the best balance of the above priorities. Bonus points that they’re the most affordable.