N52 Swap Discussion

[hubcapboy]

I think that photo is of an n52 pump, but the video is a 4 cyl. And yea... I definitely picked it because it was the funniest.

please do take the one you have apart. I’m very interested in whether removing the arm will create a lubrication problem (is the air pump somehow responsible for getting engine oil into the bearing and pump cavity?) If the arm is that easy to pull out, great... unless it means the bearing burns out or that arm fixture burns through the back of the pump case

[nando]

From the video, it looked like there was holes in the "bearing" of the pump to provide lubrication. I don't think you need that rotor arm at all.

[nando]

so yeah, you can take it out - but what I wonder is, will it just fill up with oil without the arm being in there? Some oil has to be in there to lubricate it - but without the vacuum I think it's just going to pool up in there.

Is anything else other than the brake booster connected to the vacuum source?

[hubcapboy]

I believe the exhaust flap is vacuum operated, but I don't know which models had flaps. It doesn't seem to be teed off this vacuum pump for any of the applications I see.

Thinking about the "work" being done by a vacuum pump, it's nice that just capping the outlet will basically fool the pump into thinking it's doing its job (there's no circulation, just a much smaller diaphragm.

We might conclude that the losses from the pump are 90% the bearing and 10% the pumping... there's no fluid being moved, so once it pulls down the pressure it might seriously just be spinning that stick in a "lubricated vacuum"

[hubcapboy]

https://www.eliminatorproducts.com/uploads/assets/h_testimonials/cll6clRpdHdydlR2MzV1cTBMclhZL2R1SlZJeXkyUENSMTVPUzJXY2VmNmdpbnI1eFo3aGxLc2x6Rmt3aW5VVUhhSHVDMFQrN0JKY0xBNDB5RFl1R0E9PQ==.pdf

I'll let someone else be the guinea pig for this :)

[nando]

I believe the exhaust flap is vacuum operated, but I don't know which models had flaps. It doesn't seem to be teed off this vacuum pump for any of the applications I see.

Thinking about the "work" being done by a vacuum pump, it's nice that just capping the outlet will basically fool the pump into thinking it's doing its job (there's no circulation, just a much smaller diaphragm.

We might conclude that the losses from the pump are 90% the bearing and 10% the pumping... there's no fluid being moved, so once it pulls down the pressure it might seriously just be spinning that stick in a "lubricated vacuum"

Only the 330i and 335i have it. you don't need it at all, it's just used tor very low speeds to make for a quiet idle.

[nando]

https://www.eliminatorproducts.com/u...l1R0E9PQ==.pdf

I'll let someone else be the guinea pig for this :)

The N52's cyclone oil separator already does a great job of keeping oil out - providing it's not plugged up. I don't think it even needs vacuum to work.

Using the vac pump to boost power though? well, it would be pretty easy to testy on a dyno, lol. But my guess is it doesn't do anything.

[hubcapboy]

i just realized there’s a pump on my mock-up engine...

[hubcapboy]

Recommendation from a reliable resource: Leave the wiper arm in, cap the pump, and don't worry about it. The pump won't know the difference between this state and normal operation. My observation from spinning the pump with one finger without a chain on the sprocket is that 90% of the drag comes from the bearing, 10% from the wiper arm, and my source assures me that once the pump has drawn down the vacuum, there's not any significant losses in the action of the pump (this isn't a a compressor which has to work hard to pressurize a container... once the vacuum is drawn down there's no additional work to do)

Plate arrived today to build the baffle and I couldn't stop myself from running out there to make one 90 deg bend:





The "near face" of the pan is lying on the skidplate below ready to go on when this is all worked out. There's a tray that needs a more precise bend that sits on top of this with an opening for the pickup to drop through.

I'd appreciate any input on whether this baffle design makes sense. effectively all engine oil is going to drain into the baffle area where it's captured by the flaps until it fills to the point of the overflow holes just below the tray. Whenever the oil level outside of the baffled area is lower than outside, it'll get refilled via the flaps.

I'm considering cutting every other "between piece" out between the overflow holes.

[hoveringuy]

The only time I consistently saw my oil pressure light flicker was under heavy braking pointing downhill (on a rear sump pan).

I'm not sure you need any of the overflow holes?

[nando]

yeah, I agree - cap the end that goes to the booster, and leave it alone.

Do you need that many flaps? most of the stock BMW pans I've seen only have one or two. 5 seems kinda overkill. But I've also never fabricated my own oil pan, so..

[hubcapboy]

HG: Yep. I'm completely throwing out the rear sump as a reference and basically copying the design of the m20 baffles from advanced auto fabrication, bimmerworld, and achilles. They all separate the port side and front side of the pan from a corner in the "starboard/aft" where the pickup sits. I honestly don't think I need a baffle at all, but it's useful to drop it in there while this is all apart. Do I need any of the overflow holes? I dunno. after playing with these flaps I have a feeling that once there's some hydrostatic pressure against them they're a very good seal. My fear would be that unless I have overflow holes, there's no way for the oil to really ever get to the "rest" of the sump, so why do we even have it... I could see the baffled area filling up and just backing up into the tray below the crank. I think these are a much better seal than any hinged metal flap.

N: I think one or two would be fine... I think one on each of the flat faces would probably be fine... but I bought more flaps than I'll ever use, the holes are free, and this makes me feel better about oil not getting trapped in weird parts of the pan outside of the baffle. Once I saw the flaps on one BMW design, I started looking at the flaps in general cases. Cosworth doesn't screw around when they put them in Subaru engines:



The approach seems to be "put a piece of metal where you want oil to go one direction and not the other, and if there's room for a flap put a flap in it."

[hubcapboy]

An idea that I decided to abandon is reflected in this 2jz baffle:



And this Mazda rotary baffle:



Which is separating each quadrant of the pan with solid baffling to "require" the oil to flow through the pickup well before it goes somewhere else (so rather than washing around the well, it's forced to fill it). Once I started looking at the shape of our pan, our pickup is already in a corner. I'm thinking about lining my oil drain plug up with one of the flaps so I can poke it in to drain the pan more completely during an oil change.

(this is also a subtle attempt to fill this page with photos of pans with tons of flaps so I don't look crazy)

[hoveringuy]

I think there's some comfort in the redundancy of multiple flaps, and I suspect that in static conditions they seep enough oil to keep everything equalized. Hot oil isn't very viscous so a few semi-circles at the bottom, or even just a small gap, should be plenty.

[NC325iC]

i need to turn email notifications on... Just spent a few minutes catching up a bit. Loving the progress guys, my hat off to your engineering and fab skills. Please keep me in mind for any tubing you guys need, I want to help in any way I can. Laser cut tubing, mandrel bending, anything you guys need to help button up. Please let me know, dev costs on me.