Yeah, it's a nicely made item. Mine was also nicely matched to the gasket. The cat on mine is a nice, free-flowing unit, and keeps the thing ready for the unlikely event of a visual inspection. Sounds nice, too....

 

Looks Good

 

My long term plan is to re-use the original cat from the car, I cut it out of the original broken header before I threw that away. I finally got a welder and I'm learning how to use it, all I'd need after that is some 2-bolt exhaust flanges and a bit of pipe.

Thanks man!


Also I've contacted three sandblasting shops and none have answered the phone, or any of my emails. So I'm going to try another method to de-rust the rear subframe at home. 100g of citric acid and 40g of washing soda for every l of water apparently makes a very good rust dissolver. I've ordered enough to make 40 gallons of solution, which I can soak the whole subframe and all the rusty metal parts in. This theoretically should be better than blasting because it will get into all the little areas inside the subframe.

Based off this video:

 

I de-rusted and repainted the rear subframe, sway bar, and trailing arm bushing mounts. I used the homemade rust remover referenced in post 178 above. I made 40 gallons of the solution at 60% concentration, I had to add an immersion heater to keep the bath warm, as it was making no progress in the 20-30 degree temps I was having at the time. The parts went in the bath on a Sunday, the heater was added Wednesday. The parts then stayed in the heated bath until Saturday. I then pressure washed them, removing nearly all the paint and revealing a ton of additional rust. The parts then went back in the hot bath until Sunday at which point all progress stopped as the solution was depleted. So a week of total soak time give or take. This solution worked wonders, there was a lot of rust on these parts and it removed the vast majority of it with only time.


Parts are painted, two coats of Rustoleum primer, then two coats of VHT epoxy paint. Everything wire wheeled prior to paint. The sway bar is 100% rust free, the brackets probably 99% rust free, and the subframe 95%. The inside of the subframe is a bit hard to paint and remove rust. That is sadly where the last of the rust remained, so once this is back on the car I will be fluid filming it every year. I'm hoping the Rustoleum does what it is supposed to and prevents the rust from spreading again.

I also assembled the R56 rear trailing arms with new wheel bearings, and reused the pads and rotors from before. I'm going to press new bushings into the front trailing arm bushing carriers, I can't believe BMW wants $350 for those as an assembly! New bushings are only $13 each, and I have a set of PowerFlex inserts on the shelf already to help stiffen it all up. I'm also thankful I saved those special bolts, they're $60 each to buy new! I had to beat the hell out of the drivers rear caliper to get the parking brake out of it, there was no saving that thing. A new parking brake cable is now installed and waiting for the caliper.

The subframe is now fully re-asembled and back up in the car. Heat shields are all back in place, rear shocks are back in too. At this point all that is left to do is put the exhaust back up and once the new bushings arrive, put the rear trailing arms back in. I'll then give the car a string alignment, though I'd like to get it done professionally this car is extremely low and I've already had trouble with alignment shops on cars higher than this one. I got the new control arms pretty close in length to the ones I pulled out, so it shouldn't be too far off anyway. I think I can get it dialed in alright, its only camber and toe anyway. So this is where it sits right now, the snow is starting to fall so I need to get this thing driving again because my other car is RWD and wont be safe with any snow on the ground.
ok picture time :D


in the chemical bath with immersion heater

nice and warm

after one week, ready for pressure wash

subframe didn't fully clean up

looking crusty, back into the bath

trailing arm bushings cleaned up well

both bushings were cracked

bushings removed, very crusty.

lots of metal lost to corrosion on the sway bar

Bushing carriers cleaned up

removed old stabilizer links from trailing arms...

very pitted form road salt. Came from an un-loved car :(

another few days and the subframe is clean now

applying anti-seize for the new bearings

beat this out with a hammer, took alot of force to get out.

trailing arms cleaned and dressed, ready to go in!
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Toast the kitty

"paint booth"

first two coats, rustoleum rust reformer

very pitted but still strong

earplugs used to protect threaded holes

lots of pitting, from years of rust.

pitting

second two coats, VTH epoxy paint. This stuff is strong.

Earplugs removed.

matching new control arms to old

used bolts to ensure alignment.

All four new control arms in.

Sway bar back on

ready to go in

subframe in

gas tank bolted back up, cribbing removed

nasty old control arms

this one was completely seized, never got it to move.

trash now, someone paid alot for these at one point.

rear shocks back in.

 

Nicely done.

Also, I hope you are aware of the care needed to install the shock bolt into the lower control arm.

Ignore this if the work is already done. What I have learned is that the original bolt is self-tapping. Extreme care needs to be taken with reinstalling them so that they don’t become cross-threaded. Hand thread to start them is the best way to go. Also, don’t over torque them. There is no spec for reinstalling these bolts. Only a spec for the installation, when it is cutting new threads and that is way too high for reinstalling. I used 90 ft-lbs which works for that size wheel bolts and worked for me for the last 10 years on my R56 track car.

 

Great work!

More kitteh pics!

 

I am aware that is a self tapping bolt and has caused people some serious headaches. Right now I have two brand new bolts for the shock mount point. I hadn't done any research on the torque yet, but my plan was to use blue loctite and to hand thread in the bolts to ensure there is no cross threading issue. I wont torque it until i'm 100% sure its engaged right.

The more significant thing is the self tapping bolts for the toe bearings. Those are $60 each new, which I am seriously not in the mood to pay for. So even though it may be ill advised, I'm going to re-use the old ones there. Loctite on those as well. Thoughts on that?

Will do :D

 

For now, I ended up finding a good used one from Allmag to keep the car rolling. I was all set to get the Little Orphan Annie headlights when the tariff situation from the used Aero grille I got from a guy in Italy (closest one I could find) worked itself out, but the old one developed a new issue. Not sure what happened in the interim, but the height adjuster broke on the old, crufty one, and the thing was looking at its toes. The replacement is in pretty good shape, and may come up clean with a good lens restore kit, even with my poor skills in that sort of thing. Can't complain for $128 plus shipping (got a code for 20% off the original $159.99 price). I get to keep the original look, the fancy Xenon self-leveling, and can enjoy the LED H7s in my high beams (instant DAYLIGHT!) when there's nobody coming the other way....


The one on the left is the replacement. You can see the munged up lens on the other. It made a mess of the beam, and I'm sure it scattered light enough to annoy on-coming drivers, or at least it did until the height adjuster popped and it started staring at its toes.

The lens on the replacement is fairly clear, with just a little bit of yellowing, which should clean right up.

This pic ^^^ totally reminds me of the "polite cat" meme, filtered through some kind of Tamagotchi thing:


Now I have more time, and if the tariff doesn't get refunded, maybe I can keep my eyes peeled for a set of them used (and enjoy the cost savings), as they seem to pop up now and again lately....

 

Happy Holidays!

I am not familiar with the toe bearing bolts. But in general I am not a fan of the self tapping bolts. With care I think they can be reused. The shock bolts on my R56 were replaced with Timesert steel thread inserts (which the shop messed up one with the wrong drill size and I found that it didn’t hold any torque when I went to replace the shocks a year or so later ) and conventional bolts. If I had to do it again, I would have just replaced the self tapping bolts with conventional metric bolts equivalent to SAE Grade 8. These will match the treads that are already formed and should thread in without fear of cross threading. All hand done.

As for torque, I believe there is none for a reassembly. The only torque that anyone could find was for the initial assembly and that was when the bolt was being driven in and cutting the treads. So, that torque is really high to account for the thread cutting. The amount of torque that is associated with with cutting the treads needs to be subtracted out when reinstalling the bolt. Unfortunately, that torque is unknown, to the best I could find. That is why I used the wheel bolt torque. If you find something for reassembly, please post.

As for blue LocTight, no thoughts either way…

 

I ended up doing 90 ft lbs. for both bolts. Used a new self tapper for the shock and reused the toe bushing bolt. So far so good! If they pull or start to get funny on me I'll do the timesert/helicoil. I did a bunch of reading on this, replies from WMW, fb posts and lots of info here. There's so many opinions on this, that I just decided to make it "tight". Thinking about the situation more, I opted to not use loctite and instead add a bit of anti-seize. Though it seems counter intuitive, I believe it will help prevent galling and ensure the bolt goes in smoothly without damaging the already fragile threads in the arm. The engagement felt really good, nice and smooth and torqued up really easily. I believe I made the right choice.

Appreciate all the info

 

So I should update this thread for continuity.

The rear end is all back in, the car got a quick and dirty string alignment by yours truly. As stated before; the self tappers were installed with anti-seize which I believe will prevent the threads from galling and preserve their strength a bit more. Everything went back together nicely! I sprayed the whole thing down with a thick coating of fluid film to keep the rust from re-forming.

I set the rear camber to -1.5°, toe to zero. It drives really nice! I also had a set of Bridgestone Blizzak WS90 snow tires put on, the car has excellent traction in the poor weather now. These are my favorite winter tires, I spent a little more for them than some other options that are available but I feel the performance justifies the cost. After 3 years of driving a RWD car in the winter, the feeling of safety of a FWD vehicle with proper snow tires is unmatched.

Impressions after the rear end refresh:
Substantially increased compliance and softness in the back. The old seized rear control arms really didn't move much, they were constantly binding and popping, so the ride was extremely harsh and unpredictable. Corners were weird and not the same every time. With the new parts its much more soft, less cabin noise, predictable and secure feeling. A huge upgrade. The aluminum rear arms are good, the car feels lighter and more responsive in the rear but exactly how much more is hard to say. I got those trailing arms for really cheap from a junkyard so I have no regrets at all. If I paid full price for a kit I would probably be a bit more disappointed. Again this is a street car (for now) so maybe it would be more worth it for an auto-x build.

This marks the 2nd to last big ticket item the car needs. All that's left now is the clutch, but I will wait until that fails completely before I made any moves on that.


Cheap abs sensors, one was DOA, had to reuse the old r53 one



This kit didn’t really work, ended up doing it on the floor


Nifty little camber checker



Zip ties lol

New shoes

Toe bushings

Compressed with a t bolt clamp

Press setup

Start the bushing with the clamp, remove the clamp to finish it off

All done

 

Nice work!

 

Thanks!

This was a great thing for the car, the rear end is much more well behaved now. Now I just need to get these cold starts dialed in on this ECU. Spent the last two cold mornings cranking this car like a diesel with no glow plugs lmao.

Also ordered some engine dress up goodies from Lohen, two lightweight serpentine belt pulleys to replace the ones I have that are screaming louder and louder every day and some fun valve cover bolts to replace the ones that are rusted to oblivion.

 

Yes, nicely done!

FWIW: As for the never seize, I agree with what you did. And agree with the 90 ft-lbs for the torque. Easy to check over time.

 

I can share some tables from the sample tunes that came with Bytetronik if you think it'd help give an idea about how the Siemens folks do it. There are some specific to startup. Primarily they seem to do things with timing, richer mixture, and higher idle rpm, and pay attention to engine temp as well as time after start.

I have their valve cover bolts. Got a 1/4" drive torque wrench from HF just for tightening them. Apparently torque is critical on the valve cover bolts. Those pulleys they have look nice. Let us know how functional they are....

 

I actually would like to see how that all works. I think i wont be able to copy anything but it should help me get an idea of what the stock ECU is doing.

Everything came in yesterday: Its all very nicely made, the pulleys have the bearings held in with a circlip, meaning repair would be a breeze. The valve cover bolts are pretty nice too, ordered some gaskets from FelPro to replace the tired original ones. I like that they are machined aluminum, they wont rust ever again now.

 

My old high school colors - blue (edit) Green and gold. Nice! I think I would stick with red ones, since that is my under-bonnet accent color. Recently got a black DDM sillycone intake hose to replace the red Forge, as that was trimmed for my old CAI and was a bear to connect with the new (modded) stock airbox. Too big a chunk of red anyway. Next is to clean up the intake mani I have sitting here, add a bung to put in a 1/8 npt hose barb piece for my Boost/Vac gauge, so I can get that powder coated like the supercharger and intake horns. With that big red hose gone, the horns and other red bits that I want to highlight will pop a bit more, visually. The rad hose kit is also red, but smaller and not as big a distraction from the fancy bits....

Will dig up tables for you in the daystar hours over the weekend.

 

Start-up fuel tables



Target idle speed vs. engine temperature



Idle PID control - PD part - vs engine temperature



idle PID control - i part - maps



Ignition timing startup/warmup tables


HTH! Not sure about all of what happens in the guts of the Siemens EMS2000 program to mangle these numbers into useful control of the engine - heck, not even 100% sure of table names and header labels and units (oh my!), because Bytetronik - but the PID tables probably apply to something recognizable in ECUMaster Black....

 

Happy new year!

 

happy new year to you as well!

 

This ended up being very helpful btw! I didn’t copy it but it showed me that I needed a TON more fuel at cold conditions to get the engine to crank over.


additionally my firing mode was weird, the waste spark mode on the EMU black isn’t compatible with systems that only have two coils. Setting it to fully sequential but assigning the coils like a wasted spark gave me a much better startup!

very weird, I had coil 1 on cyls 1 and 4 and coil 2 on cyls 2 and 3, but for some reason the wasted spark logic doesn’t understand that config. Setting it to fully sequential with that coil-cylinder pairing still makes the car fire as wasted spark but makes the EMU happier.

who knows!

 

Glad I could help!

This is all good info. Chasing p1689/limp here at parking lot crawl and start from stop. Working on rpm x throttle% --> maniPressure table trying to make the EMS2000 work better with the TVS900 and a stock head/cam. Will hopefully get Adrian to extract my stuff soon and transplant into an old MS5150 facelift ECU I have here, and do his magic, then once that is 100% on the money, will swap in the EMU Black and see what I can do with it. It'll be nice to have the "factory" ECU for inspection day, just in case their OBD2 reader cares about it being factory or aftermarket....

 

sounds like it’s gonna be really nice! I’ll send you a copy of my “V3 base map” I’ve come up with so you can get going on the newer version of the software when you switch over to the EMU.

i think there’s no reason to bother with v2 now that the official V3 software has been released and is out of beta. It’s just so much better!

I also got it communicating over can bus bidirectionally with my WMI module, so when the water runs out or there’s any failure detected (shorted pump/solenoid or low pressure) is triggers the check engine light and pulls timing from the car

 

Nice! That'll be a big leg up on getting mine started. EMS2000 is so poorly documented, as is Bytetronik. Everything is a big, top-secret mystery. Been using ChatGPT to root out which table axis items and units to look for in FA53. It helped me find the rpm × throttle% -> maniPressure table used as the model for supercharger behavior. I bumped it up to TVS900 airflow across the table and suddenly things like switchover to acceleration enrichment worked better. Still likely work to do in the idle and idle-adjacent cells of that table to get into the root of the implausible torque calculation behind the P1689....

Yeah, I have been kinda keeping an eye on that as it went through beta. Looks promising!

Nice! I am adding a Davies Craig Thermatic fan relay to my setup to feed power to the low speed fan wire via a resistor, to make a third, ultra-low fan speed, because the OE setup doesn't have extra goodies like that which you can set up. I bet the EMU Black could do that with just a relay, based on the engine temperature reading in the ECU....

 

The EMU black supports PWM fan control, and the only thing keeping us from using it is that our fan speeds are controlled via relay. I have a long term plan to source/design a solid state relay replacement which would allow us to accomplish two things:
1. Eliminate the failure-prone low fan resistor
2. Allow us to get rid of the fan speed states entirely, the fan would just ramp linearly up as needed.
3. Free up an output for whatever else we like

The current wiring doesn't allow this to work, the relay is triggered by the black and just switches the 12V, a large mosfet, a diode, and a pull-down resistor would probably make this work easily. I should look into doing this, could be a fun project