N52 oil pan design for Z4 engine arm based swap

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  • Striker01
    Grease Monkey
    • Jul 2011
    • 375

    #136
    Last post about this pan, I promise.

    I don't like all the scratches that ended up in the aluminum from assembly but I like the raw aluminum look. I condition wheeled most of the scratches out and then media blasted mine. Had it anodized clear to protect the aluminum, unfortunately the 40.... whatever fill rod changes color during the process. I think it looks kinda cool but use a different fill rod if you want it to stay aluminum color. At least the stud masking held up and they didn't get dissolved in the process.

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    • N4nier
      Noobie
      • Nov 2025
      • 2

      #137
      I, for one, appreciate and like the detailed posts! Solid work.

      Comment

      • Northern
        I like cupcakes & sh!tboxes
        • Nov 2010
        • 5234

        #138
        Love the pan detail posts.
        I have a weird urge to N52 swap my car now.

        Originally posted by Striker01
        On mine I was less picky and ended up chasing down multiple pin holes after it wouldn't hold pressure. Lesson learned, take the few extra minutes and prep the aluminum properly.
        Reminds me of trying to fix a broken e34 M50 pan for my old 4-door. I think I went back at it half a dozen times because every time I tested it, it leaked. That old cast aluminum was nasty to weld, even after grinding out the edges/cracks, an inch clean up with scotchbrite disk, and a thorough acetone scrub...
        Last edited by Northern; 02-19-2026, 06:07 AM.
        Originally posted by priapism
        My girl don't know shit, but she bakes a mean cupcake.
        Originally posted by shameson
        Usually it's best not to know how much money you have into your e30

        Comment

        • hoveringuy
          R3VLimited
          • Dec 2005
          • 2720

          #139
          Originally posted by Northern
          Love the pan detail posts.
          Reminds me of trying to fix a broken e34 M50 pan for my old 4-door. I think I went back at it half a dozen times because every time I tested it, it leaked. That old cast aluminum was nasty to weld, even after grinding out the edges/cracks, an inch clean up with scotchbrite disk, and a thorough acetone scrub...

          i just got done fitting a dual pressure and temperature sensor to my oil filter housing and learned a few things... As Northern said, it's more difficult welding on cast stuff, especially something that's been previously used. I first tried welding an actual NTP bung and it was a disaster! I was chasing pinholes and leaks everywhere. Finally took the approach of just building-up material and tapping that directly, which seems to be working well. The Aim is registering those values now and can't wait to log that this season!

          I was discussing this with an E90 racer and he said that the stock fluid intercooler actually works better than the big external oil coolers, which really surprised me.


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          Striker01 did a great job on his pan! He's upgrading from the steel pan.

          The steel pan was good, but the aluminum pan is better in many ways but also a little bit more difficult to fabricate. There are some tips and tricks for keeping bolt head clearance with fatter aluminum beads on the flange, for instance.

          -It has better oil control. The windage tray is fully removable and replaces rubber Cosworth flaps with stainless trap doors.
          -It uses a stock E36 OBD1 dipstick
          -Weighs around 7lbs less.
          -better heat dissipation
          -more clearance to the rack for moving engine back

          I was looking at an M20 yesterday and I'm pretty sure this pan has MORE clearance than even a stock M20!

          Here are two more teaser pics since I'm already posting....

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          Comment

          • projectJTv4
            Advanced Member
            • Sep 2019
            • 174

            #140
            I'm kinda hard headed and want to keep the m20 oil level sensor so I had to improvise with this pan. I drew a flange and had SCS bend it and add m6 studs.
            Pretty neat!

            Comment

            • benz-tech
              Grease Monkey
              • Jan 2011
              • 354

              #141
              THIS. IS. SEXY! I don’t know if I can run a steel pan after seeing this. My friend has a bed plate also. Another friend is a master at the TIG. I think the universe is trying to tell me something. Hoveringuy needs to make a CAD label that we can spot weld on so credit can be properly shown. If I can BAR mine, Cali guys will be all over this swap. And beautiful parts like this will fuel that fire
              You say "Where are your other two cylinders?"
              I say "Where's your other camshaft?"
              Frankenmotor: if an M42, M44, M20, S50, and S52 were to have a kid.

              Comment

              • hoveringuy
                R3VLimited
                • Dec 2005
                • 2720

                #142
                The oil pressure and temperature post, or how well does this pan actually work?

                See the post a few slots up for the oil filter housing pressure and temperature sensor welded into the oil filter housing, this is the video that shows ACTUAL pressures and temperature with the factor fluid cooler. The best data I had previously was that oil temperature in the pan gets up to around 265 degrees F, so the cooler obviously works well.

                I put the G meter next to the oil gauges for easy comparison, lowest oil pressure is under heavy braking, the downhill braking zone would flash my oil pressure light when I had the M54, now it stays easily above 20psi. I haven't seen any similar logs. Conclusion is that the pan works just fine.

                Also, E46 M3s aren't that big of a challenge.

                Comment

                • Digitalwave
                  is a poseur
                  • Oct 2003
                  • 6298

                  #143
                  Some random thoughts from a former E30 guy that has spent this decade racing N52 powered E90s:
                  • The fact that this design is 'open source' is absolutely awesome
                  • 5 3/4 qts seemed crazy to me, 4 1/2 even more so. We run 8 qts in stock pans and 9 qts the aluminum Bimmerworld pan.
                    • I'm not smart enough to make any argument about this being a bad idea, but it would make me uncomfortable
                  • The rubber baffle flaps are a good idea and we had them in the Bimmerworld pans. They get the job done. The Lotus guys that run them say the service life is about 2 years. YMMV.
                  • There are flush drain plugs you can weld into the bottom of the pan so you don't have to fight with locating the side bung as low as possible. They seal with an o-ring, though, and they are more prone to weep than a crush washer. But you'll probably get more out during an oil change than the side bungs.
                  • In the rear sump config, stock pans, stock pans with baffles, and the Bimmerworld aluminum pans all perform about the same. They all have pressure drops in high G braking zones, especially when followed by left handed corners.
                  • Despite the pressure drops, if we are diligent about keeping the oil fill level high (despite moderate oil consumption on track), we could maintain 8psi/1k RPM in all situations.
                  • The video in the last reply would have had me pulling my motor out for a rebuild. 30psi above 5,000 rpm, even almost up to 7,000 rpm does not seem acceptable to me. Many times in the video the pressure is still in the 30s at redline.
                  • Rod bearings have been less of an issue than we expected them to be.
                  • Some N52s shed a lot of magnesium flakes that hopefully get caught in your filter.
                  • I'm surprised nobody is selling an N52 swap pan on the market yet, as the swap is obviously a great option these days.

                  RISING EDGE

                  Grassroots racing, properly overthought.

                  Comment

                  • Caperix
                    Advanced Member
                    • Feb 2018
                    • 190

                    #144
                    Originally posted by Digitalwave
                    Some random thoughts from a former E30 guy that has spent this decade racing N52 powered E90s:
                    • The fact that this design is 'open source' is absolutely awesome
                    • 5 3/4 qts seemed crazy to me, 4 1/2 even more so. We run 8 qts in stock pans and 9 qts the aluminum Bimmerworld pan.
                      • I'm not smart enough to make any argument about this being a bad idea, but it would make me uncomfortable
                    • The rubber baffle flaps are a good idea and we had them in the Bimmerworld pans. They get the job done. The Lotus guys that run them say the service life is about 2 years. YMMV.
                    • There are flush drain plugs you can weld into the bottom of the pan so you don't have to fight with locating the side bung as low as possible. They seal with an o-ring, though, and they are more prone to weep than a crush washer. But you'll probably get more out during an oil change than the side bungs.
                    • In the rear sump config, stock pans, stock pans with baffles, and the Bimmerworld aluminum pans all perform about the same. They all have pressure drops in high G braking zones, especially when followed by left handed corners.
                    • Despite the pressure drops, if we are diligent about keeping the oil fill level high (despite moderate oil consumption on track), we could maintain 8psi/1k RPM in all situations.
                    • The video in the last reply would have had me pulling my motor out for a rebuild. 30psi above 5,000 rpm, even almost up to 7,000 rpm does not seem acceptable to me. Many times in the video the pressure is still in the 30s at redline.
                    • Rod bearings have been less of an issue than we expected them to be.
                    • Some N52s shed a lot of magnesium flakes that hopefully get caught in your filter.
                    • I'm surprised nobody is selling an N52 swap pan on the market yet, as the swap is obviously a great option these days.
                    Did you have the S55 pan/pump or just a modified n52 pan with baffles. The s55 uses a dual pickup oil pump that is considered to be the fix for n55 cars with oil pressure issues. I can't find any documentation of it being run on an n52 but n52 uses the same oil pan & chain drive as a n55 so in theory it should work. Now for e30 applications I don't think any of the few manufacturers of rear sump e30 subframes have tested with the s55 pan using z4 arms so no telling if that will fit.

                    Comment

                    • Digitalwave
                      is a poseur
                      • Oct 2003
                      • 6298

                      #145
                      I don't know anything about S55 stuff. We've run fully stock pans, stock pans with Condor baffles welded in, and Bimmerworld aluminum pans (these have 12 of the rubber flappy baffles around the pickup). The Bimmerworld pan comes with its own pickup, but its not drastically different than stock.

                      RISING EDGE

                      Grassroots racing, properly overthought.

                      Comment

                      • hoveringuy
                        R3VLimited
                        • Dec 2005
                        • 2720

                        #146
                        Originally posted by Digitalwave
                        Some random thoughts from a former E30 guy that has spent this decade racing N52 powered E90s:
                        • The fact that this design is 'open source' is absolutely awesome
                        • 5 3/4 qts seemed crazy to me, 4 1/2 even more so. We run 8 qts in stock pans and 9 qts the aluminum Bimmerworld pan.
                          • I'm not smart enough to make any argument about this being a bad idea, but it would make me uncomfortable
                        • The rubber baffle flaps are a good idea and we had them in the Bimmerworld pans. They get the job done. The Lotus guys that run them say the service life is about 2 years. YMMV.
                        • There are flush drain plugs you can weld into the bottom of the pan so you don't have to fight with locating the side bung as low as possible. They seal with an o-ring, though, and they are more prone to weep than a crush washer. But you'll probably get more out during an oil change than the side bungs.
                        • In the rear sump config, stock pans, stock pans with baffles, and the Bimmerworld aluminum pans all perform about the same. They all have pressure drops in high G braking zones, especially when followed by left handed corners.
                        • Despite the pressure drops, if we are diligent about keeping the oil fill level high (despite moderate oil consumption on track), we could maintain 8psi/1k RPM in all situations.
                        • The video in the last reply would have had me pulling my motor out for a rebuild. 30psi above 5,000 rpm, even almost up to 7,000 rpm does not seem acceptable to me. Many times in the video the pressure is still in the 30s at redline.
                        • Rod bearings have been less of an issue than we expected them to be.
                        • Some N52s shed a lot of magnesium flakes that hopefully get caught in your filter.
                        • I'm surprised nobody is selling an N52 swap pan on the market yet, as the swap is obviously a great option these days.
                        -The rubber baffle flaps work fine, but there are two risks. 1). If they are not genuine Viton they will harden very quickly and then they will prevent oil from reaching the sump and 2) if they are not changed on an interval then it's a big "?". I went with metal hinges on the new one to preclude that.

                        -I don't have any real basis to say what the "correct" oil amount is. From an engineering perspective, what is 8 quarts of oil doing in the sump that 5 quarts is not doing? I think it's important for oil to have time to settle-out any aeration and for it to be cooled, but for me the cooling is mostly done in the cooler. I have a tradeoff oil capacity between making the pan deeper, which increases risk of impact, or wider. It's constrained going forward or to the passenger side by the bolts unless i make bolt passages through the pan which increases complexity A LOT!

                        -I don't love the idea of things on the bottom of the pan. The side plug works fine and I'm not worried about it getting hit or scraped.

                        -I was surprised at the amount the pressure fluctuates in the video, as well, even during straight-and-level driving; sometimes at 35, sometimes at 50..Is it really accurate? I don't know if there's sensor noise, air in the oil or what, but I will be collecting more data and analyzing further. The good news is that I used to get the actual oil pressure warning light (<7psi!) during heavy, downhill braking. Not any more!

                        I wouldn't claim that his pan is a solution for endurance racing or anything like that, but I send the files out at least a few times per week so it does make the N52 swap accessible to the E30. There has even been at least one FRS N52 conversion because of it.

                        I've sent the files to Kyle at Harper Fab and he's interested in getting into the N52 pan game, we'll see.
                        Last edited by hoveringuy; 04-24-2026, 12:12 PM.

                        Comment

                        • s50joe
                          Noobie
                          • Dec 2024
                          • 21

                          #147
                          Are you consistently getting that pressure drop every lap at the same points of the track? If so, I'd say it's probably accurate. Could be frothing oil since the pan has low capacity.

                          I have been monitoring the oil pressure on my s50 with an achilles baffled oil pan, I can post those logs for comparison if it's interesting. I am having some pressure drops in turns but Mino and achilles looked at them and said it looks normal and the important thing was I had good oil pressure when WOT. The pressure drops I am getting under cornering aren't as concerning since the engine isn't under heavy load at those points.

                          Based on that, seeing your pressure drop to 30 WOT at 7k RPM on a straight away seems not great.

                          I have some things I'll being doing if USPS finds my package to try to further improve my situation and if it doesn't improve its a choice between accusump or a harper oil pan (or just living with it). Harper doesn't have logs for improvement over normal e34 pan so I'll have to be the test subject.. But I don't think he's planning to take more preorders until July so it'll likely miss this season. In the meantime, I'd installing a windage tray (my engine didn't come with one when I bought it ~18 years ago) and a crank scraper. Trying to keep as much oil in the pan as possible and as little air in the oil. Will see how much of an improvement it makes.

                          I could measure the difference in oil pressure going from baffled e34 oil pan full (6.5qts, oil at top of fill line) versus 1qt overfilled. With 6.5wts my standalone ECU was kicking in to cut engine power in a few corners at The Ridge. With 7.5qts it happens briefly at Turn13 sometimes, other times no. And the oil pressure log shows noticeable better oil pressure all over the track.

                          Comment

                          • Caperix
                            Advanced Member
                            • Feb 2018
                            • 190

                            #148
                            Originally posted by Digitalwave
                            I don't know anything about S55 stuff. We've run fully stock pans, stock pans with Condor baffles welded in, and Bimmerworld aluminum pans (these have 12 of the rubber flappy baffles around the pickup). The Bimmerworld pan comes with its own pickup, but its not drastically different than stock.
                            S55 uses a duel pickup oil pump. The second pickup in the front "sump" is right at the turbo oil drain so I'm not sure if it would make as big of a difference on the n52. It has shown to make big changes in oil pressure on n55 engines though. It may be worth considering using for future pan designs.

                            Comment

                            • hoveringuy
                              R3VLimited
                              • Dec 2005
                              • 2720

                              #149
                              Originally posted by s50joe
                              Are you consistently getting that pressure drop every lap at the same points of the track? If so, I'd say it's probably accurate. Could be frothing oil since the pan has low capacity..
                              So, interestingly, adam.nonis was looking at the pan of a stock N52 and determined that at "full" the the factory oil level is significantly above the pan gasket flange line. Mine is still a quart below that line at "full" when it has about 5 quarts. I could easily add several more quarts and still be below the OEM line.

                              Comment

                              • Digitalwave
                                is a poseur
                                • Oct 2003
                                • 6298

                                #150
                                I've never used an Accusump personally, but I don't think it would be able to keep up with the pressure losses being shown in hoveringuy's video, because the tank would be drained and it wouldn't be able to recover fast enough.

                                I have two of the Bimmerworld oil pans, one with the Viton flaps, one with piano hinges. I put fresh Viton flaps on and put that pan on the car. They both have their pros and cons IMO; the Viton hardens eventually, and the piano hinges eventually fatigue and snap (this probably takes longer than the Viton takes to harden).

                                RISING EDGE

                                Grassroots racing, properly overthought.

                                Comment

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