heinzboehmer's 2002 Topaz 6MT Coupe

[heinzboehmer]

Maybe I missed it, but what printer are you using? Do you find that the PET-CF wears out the hot end faster? Also, are you concerned about fumes at all?

Using a Bambu P1S, but I reeeally want a dual nozzle printer. That upgrade will probably be coming soon, but this one has been great for now.

And +1 to both things that Obioban said. The P1S has a filter on the chamber exhaust fan, but I still keep it in a separate room in the garage level that doesn't get much human traffic. I'll open up some doors to the outside if I'm printing stinky stuff for a long time and that seems to keep the fumes under control.

[Obioban]

Maybe I missed it, but what printer are you using? Do you find that the PET-CF wears out the hot end faster? Also, are you concerned about fumes at all?

You just need a hardened nozzle… And air filtration on the printers exhaust

[Arclitgold]

Maybe I missed it, but what printer are you using? Do you find that the PET-CF wears out the hot end faster? Also, are you concerned about fumes at all?

[heinzboehmer]

On another note, I still can't get over how cool the PET-CF prints come out looking. Blows my mind every time.

Here's a third of the cabin air filter housing:




(Yeah the amount of supports needed is insane, but want to print it this way to orient the layer lines in the direction that will see the largest loads. Mostly worried about me or someone else leaning on it when it's installed and snapping it in half.)

[heinzboehmer]

Ha, yeeeah...

Someday

[Bry5on]

You have described exactly why I haven't done anything about exterior aesthetics either

That makes three of us. Just add two carbon doors to the picture on top of the roof and trunk/hatch

[karter16]

You have described exactly why I haven't done anything about exterior aesthetics either

[Arclitgold]

Ha!!! This train of thought is how so many of my projects go…..

[heinzboehmer]

Took some pressure data yesterday, but I don't think I've gotten to a point where I truly understand how the results tie into the other changes I made to the filtration system. I'm gonna spend some time reading up on this a bit more before I draw any conclusions.

In the meantime, parts arrived, so I finished fixing the damage I caused to the car with my little off road adventure.

Old shear plate off:




Very impressed with how well this thing took the hit. Absolutely no underside damage except for this part and some scuffs on some of the plastics. Also, it looks like the dents in the middle of the plate are from improper jacking and not from the hit, which means this thing barely dented at all! Crazy.

Couple of the bolts had seen better days, but still looking pretty great for slamming against concrete at 80mph!




And everything is still perfectly dry and in its place under there, good stuff:



Got a bit overzealous with the impact when installing the new plate and damaged about 1/3 of the threads in one of the FCABs. Rescued it with a tap and it torqued up fine, but it is aluminum, so I've ordered a new set and will swap those in next time the plate comes off.

Shiny:



Lastly, something ripped off one of my splitters when I went off track. For a bit of context, the car was sold to me with some low quality black ABS splitters that I did not like. Shortly after buying (and before removing them), I took the car on a ski trip and ripped the driver's side splitter off with a chunk of ice that was hidden under some snow, damaging the bumper in the process. Instead of properly fixing, I went down the cheap and lazy route of replacing with some low quality CF splitters and it's been like that since.

I've never loved the look, so maybe it's time to get rid of them. But since the bumper needs a respray, might as well get a euro bumper and start fresh. Hmm, one of the fenders doesn't really match, so might as well paint that too. Oh and the front end has a bunch of rock chips, so let's go ahead and add the other fender, hood and mirrors to the list. Wait, rear quarters have rock chips and the clear is very thin on one side, so those get added too. I guess the doors won't match anymore... yeah, seems reasonable to spray those as well. Oh! I do want to color match my future CF roof to the body, so let's bump the priority of that project up and get it installed before the paintwork.

Looks like the only panels we aren't painting are the trunk and rear bumper. Might as well get a CSL trunk and spray the entire car at once so that everything matches.

Hold on? You're saying that both the price and time required for this side project has grown by a couple orders of magnitude? Damn...

So I did the sensible thing and slapped the spare splitter I had in the junk pile on:



Whatever. I don't see these dumb things when I'm driving, so who cares. I'll get to aesthetics whenever I'm done with more interesting things

[heinzboehmer]

Alright, experimental setup ready.

Got myself a cheapo digital manometer, since I thought it would be a bit more versatile than the fluid ones. I really have no way of checking precision or accuracy, but the readings are very repeatable, so I'm gonna say it's good enough for this test.

Started by sealing the prototype with some random hardware store window seal tape. This is as good as it's gonna get, since the printer has been busy with the PET-CF parts and I have yet to get to the gaskets. Don't think this would hold up to engine bay temps, but that doesn't really matter for a static test with the engine off.



I then drilled a hole in the filter cover and sealed one of the manometer hoses against it.



(Sorry, what was that? No, I didn't drill the first hole in the wrong spot and then had to cover it up. No idea what you're on about...)

Plan is to take all measurements with the hood closed, to replicate real operating conditions. Easy enough to route the hose out through the hood grill and then connect it to the manometer. Reference hose got taped to the windshield to make sure that's the same throughout the tests:



(Ignore the reading for now, I'll get some real data tomorrow.)

I also spent some time messing with the climate control settings to find what resulted in the biggest reading on the meter with all the plastics installed, but no filters. The readings were fairly small even if I covered a large portion of the intake area, so I figured that getting the unrestricted pressure difference as high as possible would give me more reliable data, as I wouldn't be running into the resolution limits of the measurement device as much. This is what I landed on:



Lastly, just want to write something down that was on my mind throughout this setup process:

I don't think the way I've set it up will give accurate data on the pressure drop across each filter. I played around with putting the reference tube under one of the filters, but it was hard to put it in a spot where the readings were repeatable. Also, swapping out the housings means moving the reference, so I just decided to instead take relative measurements with ambient pressure as the reference. This means that my results will really only tell me how the stock and X5 filters behave in relation to one another. However, comparing to stock (i.e. what the system was designed for) is kinda the only thing I care about, so this testing should still result in some valuable data

[heinzboehmer]

I bet it’ll be fine, it’s not going to be perfectly sealed to truly matter. The inlet into the blower case isn’t much bigger than those filters, and honestly I bet it’s smaller.

Yeah fair point. It definitely doesn't feel like these are a restriction at all, but I do love me some data.

WestBankM4 said I can borrow his stock housing this weekend, so will get data soon.

and those are recirc air only filters in the F25, the others are fresh air only.

Good to know!

I'm glad Corteco makes this activated carbon version of the filters, even though BMW specs them as standard paper ones. It's like they knew I was gonna need them

[George Hill]

I bet it’ll be fine, it’s not going to be perfectly sealed to truly matter. The inlet into the blower case isn’t much bigger than those filters, and honestly I bet it’s smaller.

and those are recirc air only filters in the F25, the others are fresh air only.

[heinzboehmer]

A manometer through a hole in the filter shroud is probably how I’d do it. Easy enough and cheap.

Oh, duh. For some reason my mind went directly to building some sort of test setup that could seal to both sides of the filter, pull air through it and get a bunch of telemetry out. Been building a bunch of testbeds at work recently, so might be a bit stuck in that mode still

Appreciate the guidance, as always. Will have to find someone to steal the stock filter housing from for testing, since I cut mine up.

Edit: You know, now that I think of it, I'm gonna have to swap the firewall plug too, so it won't be an apples to apples comparison.

Eh, I guess it's fine. Definitely not building the custom bench testing setup.

[Bry5on]

There's actually two sets of filters in the F25 X3. One set is at the fresh air intake in the engine bay and the other set (this one) is behind the glovebox. I'm not positive if these ones are used in series when pulling air from the exterior or if they're only used for filtering recirc air. From videos, it looks like the two glovebox filters live next to each other, not stacked (i.e. they're in parallel), but again, not 100% on this.

I can't feel any difference in flow or hear any difference in blower rpm with and without the filters, but that observation is terribly unscientific, so not sure it's worth anything.

Can you think of a good setup to measure pressure drop in the garage? Would be good to quantity these against the E46 filter, but I was unable to find those specs anywhere.

A manometer through a hole in the filter shroud is probably how I’d do it. Easy enough and cheap.

[heinzboehmer]

Looking great man! Are those two filters used as just a pair in their OEM application, or are there more of them? Thinking of flow area/pressure drop. I remember how tough packaging was for hepa filters (extra pressure drop for hepa) when we were designing some of the Nio cars.

There's actually two sets of filters in the F25 X3. One set is at the fresh air intake in the engine bay and the other set (this one) is behind the glovebox. I'm not positive if these ones are used in series when pulling air from the exterior or if they're only used for filtering recirc air. From videos, it looks like the two glovebox filters live next to each other, not stacked (i.e. they're in parallel), but again, not 100% on this.

I can't feel any difference in flow or hear any difference in blower rpm with and without the filters, but that observation is terribly unscientific, so not sure it's worth anything.

Can you think of a good setup to measure pressure drop in the garage? Would be good to quantity these against the E46 filter, but I was unable to find those specs anywhere.