heinzboehmer's 2002 Topaz 6MT Coupe

[heinzboehmer]

I thought the temp for annealing was quite a bit higher than powder coating temps?

Maybe annealing is not the most precise word to be using here. What I mean to say is that I don't want to significantly affect the yield strength of the material by exposing it to higher temps than it will see in the engine bay. Thermocouple data says that the parts will likely never see above 90C, so anything past that requires scrutinization, to keep the brain happy.

Was looking into this last night and found a bunch of literature on AlSi10Mg (e.g. 1, 2, 3, 4, 5, 6).

With a bit of biochemical neural networking (i.e. lots of switching tabs to compare results ), I've arrived at 150C being the max "safe" temp I'd like to expose the alloy to. A bit conservative, based on some of the results in the papers, but I don't have a way to test the parts to failure, so would rather stay on the safe side.

Seems like powder coating cure temps are closer to 200C and I really don't trust some random shop to not crank the oven up arbitrarily, so that's why that process is ruled out. Other more common alloys (e.g. 6061) seem a little less susceptible to those temps, but strength still drops fast as the temp starts climbing.

Blast and then anodize? Powder coat will also chip off under and around the bolt heads.

This was gonna be my next approach, buuut then I reached out to the guy who cerakoted my brake calipers and was informed that there are some formulations that can fully cure and bond to aluminum at just 82C.

I have not treated my calipers with any care at all and the finish still looks brand new. I've smacked wrenches/wheels/rocks into them and have hosed them down with brake cleaner plenty of times, but have yet to affect the coating.

Here's a pic I took a few minutes ago:



Calipers are disgusting and have been bathing in track pad dust for a while, but the cerakote is showing no signs of wear.

Agreed that coatings will likely still chip under bolt heads given enough time, but as long as they don't do this during the first torque cycle, I'll be happy:



I'm essentially trying to replicate the durability of the BMW paint/coating. It does chip away with time under bolts heads, but it doesn't fail catastrophically.

Heinz, all these needed was a can spray

I do agree, buuut:

Painting is fucking annoying, and sanding 1k times more.

I absolutely hate painting stuff. It never comes out how I want it to and prep is so boring to me. I thought if I outsourced this, I would get a better finish and also have to do zero work. Not sure I was in the right here, though.

I did think of taping the bearing surfaces, but figured that if BMW got away with painting them, I could too. Also, I thought the parts would look a little weird with unpainted surfaces, since some of them are rather large.

I'm pretty confident the cerakote will work out well. My brake calipers have taken a beating with essentially no wear.

[maupineda]

Heinz, all these needed was a can spray. You should have taped the bearing surfaces.

I’d leave as is. Painting is fucking annoying, and sanding 1k times more.

Since they are fresh get paint removal and see it comes off if you want to redo them

the aircraft paint remover works good

[bigjae46]

Brackets are back and, unfortunately, I think I made the wrong call by going with paint.



This specific paint is too glossy and I feel like it just screams "look at me!". Not a fan of flashy stuff. But whatever, it's a part hidden in the engine bay, who cares.

The real problem is with the mechanical properties of the paint. It didn't seem to adhere properly and most of what was under the fasteners ripped off when torquing. It also feels extremely squishy and I do not trust that these parts will stay torqued like they should over time. I don't know if this was caused by poor prep, by the "high temp" paint, by the paint having been laid on too thick or by all of the above.

I would love to powder coat these parts and get it over with, but I'm afraid of accidentally annealing the strut tower brackets during the cure step. I think cerakote makes some low temp stuff, so will probably end up looking into that.

Sigh...

Blast and then anodize? Powder coat will also chip off under and around the bolt heads.

Carbon fiber would look better :P

[karter16]

Brackets are back and, unfortunately, I think I made the wrong call by going with paint.



This specific paint is too glossy and I feel like it just screams "look at me!". Not a fan of flashy stuff. But whatever, it's a part hidden in the engine bay, who cares.

The real problem is with the mechanical properties of the paint. It didn't seem to adhere properly and most of what was under the fasteners ripped off when torquing. It also feels extremely squishy and I do not trust that these parts will stay torqued like they should over time. I don't know if this was caused by poor prep, by the "high temp" paint, by the paint having been laid on too thick or by all of the above.

I would love to powder coat these parts and get it over with, but I'm afraid of accidentally annealing the strut tower brackets during the cure step. I think cerakote makes some low temp stuff, so will probably end up looking into that.

Sigh...

I was really surprised when I got my rear RACP bar powder coated. The guy asked what I wanted and I said gloss black, and he looked at me and said “are you sure?” And showed me gloss black, and I thought it looked good. Then he showed me “satin semi gloss” and it was better, then he showed me matte and that was the best of the lot. Very similar to the OE stock strut bar finish so that's what I went with.

I thought the temp for annealing was quite a bit higher than powder coating temps?


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[heinzboehmer]

Brackets are back and, unfortunately, I think I made the wrong call by going with paint.



This specific paint is too glossy and I feel like it just screams "look at me!". Not a fan of flashy stuff. But whatever, it's a part hidden in the engine bay, who cares.

The real problem is with the mechanical properties of the paint. It didn't seem to adhere properly and most of what was under the fasteners ripped off when torquing. It also feels extremely squishy and I do not trust that these parts will stay torqued like they should over time. I don't know if this was caused by poor prep, by the "high temp" paint, by the paint having been laid on too thick or by all of the above.

I would love to powder coat these parts and get it over with, but I'm afraid of accidentally annealing the strut tower brackets during the cure step. I think cerakote makes some low temp stuff, so will probably end up looking into that.

Sigh...

[heinzboehmer]

It's actually the reverse of that -- it's just a dumb display that the radio and CCM write to

Oh even better!

R/T is a toggle, and with the BlueBus installed you'll have issues implementing this as the BlueBus advertises itself as a phone module, so the R/T button will dutifully tell the BlueBus and radio that the Telephone and / or Radio has control of the display(s).

What I would do is use this to your advantage: when TEL "control" mode is engaged, map the up and down arrow buttons on the MFL to cycle your display. From the factory, the use case of this mode was to scroll through your contact list on the factory phone.

Hmm, I guess I hadn't considered the use case where the BlueBus isn't the main focus (I don't think I've ever used the radio or CD functionality since I installed the BlueBus), but definitely something worth thinking about. Thanks for the callout.

Does the BlueBus toggle the TEL/RAD mode on boot so that it has control of the screen? If so, do you foresee any issues with treating any R/T button press as an event and then immediately broadcasting the command to put the systems on the bus into the mode that the BlueBus expects them to be in?

[t3ddftw]

I guess maybe swapping the entire E39 cluster over could work, but I think it would look out of place in an E46.

The pinouts are considerably different, and I don't know that it's possible to code it to work with an E46, especially as it expects a dedicated check control module.

The high OBC also broadcasts all of its UI commands/decisions on the I Bus

It's actually the reverse of that -- it's just a dumb display that the radio and CCM write to

rough with some other button (probably R/T on the steering wheel). Plan is cycle through

R/T is a toggle, and with the BlueBus installed you'll have issues implementing this as the BlueBus advertises itself as a phone module, so the R/T button will dutifully tell the BlueBus and radio that the Telephone and / or Radio has control of the display(s).

What I would do is use this to your advantage: when TEL "control" mode is engaged, map the up and down arrow buttons on the MFL to cycle your display. From the factory, the use case of this mode was to scroll through your contact list on the factory phone.

-Ted

[heinzboehmer]

It would be fun if we could get the e38/e39 IKE display to work, in place of the factory door/center/SMG displays.

High OBC in the E46 cluster would be awesome.

Unfortunately, the cluster boards aren't modular at all, so there's no way to just move the high OBC screen over to the E46 cluster. Proper way to do it would be to design some frankenstein PCB that can host both the E46 non-screen cluster electronics and the E39 high OBC, but that's way more work than I'm willing to put into this.

I guess maybe swapping the entire E39 cluster over could work, but I think it would look out of place in an E46.

The high OBC also broadcasts all of its UI commands/decisions on the I Bus, so it would be super simple to have the BlueBus highjack the pages that are cycled through with the BC button on the indicator stalk. Basically just have it wait until it sees the page index drop from some positive number to 0, then have it display any pages it wants to and once it reaches its own last page, set the high OBC back to its 0th page.

With the low OBC in the E46, I'm gonna have to implement an extra "group" of pages that can be cycled through with some other button (probably R/T on the steering wheel). Plan is cycle through all pages in that extra group and drop back to the "normal", BC-button controlled pages once the end is reached.

Something like: <current stock page (e.g. outside temp)> --> Gear --> Oil temp --> Coolant temp --> CAN wheel speed --> <anything else that can be displayed with the display limitations> --> <current stock page>

Since each extra page is just gonna be a random number displayed on the cluster, I also plan on having the page name displayed on the CD53. A bit of a clunky implementation, but it's the best I can come up with considering all the limitations that the low OBC has in our cars.

[Obioban]

Also, finished running through all Data[1] values and only came close to dying of boredom 15 or 20 times.

Anyway, this is how the values are encoded, to the best of my understanding:



Full investigation here if anyone is curious: https://docs.google.com/spreadsheets...it?usp=sharing

Worth noting that there is no x1000 multiplier. I must have sent 10x100 and seen 1000 earlier or something along those lines.

Even with the multipliers applied, the weird base10/16 counting still happens. I'm starting to wonder if this is an undefined-behavior-type bug/oversight. Maybe the mi/km theory has some credence and BMW only ever planned to display max 10mi/16km for each of the multiplier stages.

Regardless, the x100 multiplier still works with the 165 max. Not that I see it being particularly useful, but it's good to know that you can go that high:



And yes, you can display this:



Cute.

Next up is figuring out the D-Bus -> I-Bus diagnostic message relaying. As far as I can tell, all I need to do is tell the cluster to relay the message to I-Bus by sending a specific D-Bus command, but we'll see if it's actually that easy.

I'm planning on doing all processing on Gauge.S and sending a single byte that encodes both the gear and the possibility of a money shift. Hoping to just send out the message on a gear change, but unsure if Gauge.S offers that level of granularity. Not gonna lie, I'm not super excited to interface with the Gauge.S SW again... It seems to be a struggle every time.

It would be fun if we could get the e38/e39 IKE display to work, in place of the factory door/center/SMG displays.

It handles all that functionality on those cars (well, not SMG), and is much more versatile-- e.g. displays track name, etc.

[heinzboehmer]

Tested the engine today and absolutely no movement at all on the pressure gauge.

Revving slow, revving fast, sitting at idle, nothing. I also disconnected the separator hose and covered the outlet with my finger. Felt pressure build up immediately, so it seems like everything is working as expected. Bummer.

I guess it just decided to leak then? Cool.

I'll take the intake (and maybe VANOS valve body) off later and investigate some more.

[George Hill]

Works on Al too

I totally read that as A "i" lol

[bigjae46]

Try the old IR dye in the oil trick?

[heinzboehmer]

Assembled the tester, plugged the PCV outlet with a glove and pressurized the crankcase:

Holds pressure, nice!

Gauge isn't registering anything because I put very little air into there. I didn't want to push out any seals.

Will test with the engine running later.

[jayjaya29]

I've found that the torch trick works with Al crush washers as well, its just harder to judge temp with them as they will melt before glowing noticeably. With a propane torch, I just get them glowing and quench.

Huh TIL, guess I'll keep em around as well from now on.

[heinzboehmer]

Also, to the surprise of absolutely no one, the slathered RTV approach did not work.

Sooo this is printing now:




I plan on transferring both the seal and the metal retainer over from the cheapo cap.

I also plan on printing it in the orientation shown in the first pic, so that the perimeters of the NPT threads are one continuous extrusion and the part doesn't split as soon as I screw something into them. Unfortunately, this means that if the part sees a failure along the layer lines, there's a chance that the metal retainer (and some plastic debris) will drop down into the engine.

Scenario above is probably unlikely, but it makes me paranoid, so I added features for four M3 screws to reinforce the part. Easier to see in a cross section: