Announcement

Collapse
No announcement yet.

SNAFU; high performance 318is build that lives up to the name, Turbo M42 ➞ Turbo M20

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    Originally posted by varg View Post
    Wouldn't cut the flange since it might wind up worse due to residual stresses
    Agree 100%, but I think it would also take less force to straighten it when you tighten it again if you're only fighting the runners instead of runners+flange?

    Corky Bell has a small section on this and mostly says that sectioning it into smaller flanges prevents it from warping in the first place.
    He claims that warping is caused by a combination of a temperature gradient across the flange (hottest in the middle) and between the flange and runners (runners expanding more as the flange heatsinks to the head)

    Separating the flange to mess with the thermal gradient across the flange, but I don't see how it would change the second half.
    And then you're left with a bunch of small flanges which might relax in the L/R Up/Down directions and give you problems that can't be solved with a belt sander...
    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


      Also I think the D610 is great, and I've been watching D600/D610 on ebay for a while because they seem like the best deal going if I want to stay Nikon.
      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


        Originally posted by Northern View Post

        Agree 100%, but I think it would also take less force to straighten it when you tighten it again if you're only fighting the runners instead of runners+flange?

        Corky Bell has a small section on this and mostly says that sectioning it into smaller flanges prevents it from warping in the first place.
        He claims that warping is caused by a combination of a temperature gradient across the flange (hottest in the middle) and between the flange and runners (runners expanding more as the flange heatsinks to the head)

        Separating the flange to mess with the thermal gradient across the flange, but I don't see how it would change the second half.
        And then you're left with a bunch of small flanges which might relax in the L/R Up/Down directions and give you problems that can't be solved with a belt sander...
        This is exactly what I was going to point out / ask. I have the turbo manifold pictured below, and the flange is clearly warped out of the box.

        IIRC, Corky's thought process for sectioning a long manifold (he specifically calls out the L6 configuration):
        • Repeated heating will warp the flange, causing you to loose flatness, resulting in a bad seal
        • Heating the metal will cause it to grow, so cylinders 3&4 will see almost no flange movement, but cylinders 1&6 will see a large lateral shift (or at least lateral forces) which could shear exhaust studs
        It also makes sense to me that trying to flatten a 6-cylinder flange has a lot more to fight against (flange and runners) than trying to flatten a 3,2,1-cylinder flange. I was considering cutting mine in half, then belt-sanding the two halves flat to each other. Thoughts?



        The turbo flange is an even worse mess....

        sigpic
        1987 - 325i Convertible Delphin Auto [SOLD], 325i Convertible Delphin Manual [SOLD]
        1989 - 325i Convertible Bronzit m30b35 swapped [SCRAPPED], 325i Sedan Alpine Auto[DD]
        1991 - 325i Coupe Laguna Manual [Project], 535i Sedan Alpine [SCRAPPED]

        Comment


          Thermal expansion coefficient is units of length per unit of length. The further out you are on the piece of material the greater the difference in position is as it heats, but lengthwise movement of the flange due to thermal expansion is not the main issue, it's the residual stresses on the pipes, welds and flange from when it was welded together, which are pulling it out of flat. Warps are unavoidable because of the nature of the process so it's better to weld to thicker than required flanges and machine them flat, skilled fabricators know this, outsourced factory workers do not care, if they even know it. And they don't seem to machine the stuff after the welding process. The order of the welds and position of the pipes will change how it warps from initial fabrication. Mine was bowed such that the ends were further from the head than the center. This deformation is preferable because thermal expansion actually tended to flatten the warped header flange, the outer pipes are longer and expand more, and the "pulling in" the welds did relaxed as they expanded unevenly vs the head facing surface of the flange. This is why my header leaked a lot less when hot. It ticked horribly when cold but you could barely hear the leakage after the car warmed up for a few of minutes. Once the flange is machined flat and clamped properly (no missing hardware) it's less likely the thermal expansion of the pipes will tend to make it leak because of the clamping, though the heat cycles can loosen the hardware. I have the added benefit of having mine flattened after many heat cycles; it's not likely it will warp significantly in use from its current state. Post weld heat treatment can reduce the residual stresses and lessen the tendency to warp, but it's not practical for fabricators because of how large the header is.

          Slicing it apart is a gamble probably not worth taking. Depending on the amount of residual stress on any given piece of the flange, when you slice the connecting parts it will 'spring' back to where it wants to be, which could be far worse than it was with the warp since the flange is constraining some movement. What if it twists and you can no longer line one flange up with the studs? As an aside, I would be shocked to hear of thermal expansion ever shearing an exhaust stud even on a long I6 flange, improbable. Would require a long flange, with relatively poor fitment and high flange temperatures even with 304SS (high thermal expansion coefficient relative to mild steel).

          The exhaust stuff is the only thing that makes me miss my previous turbo 4s, especially my turbo redblock. The shorter flange and well designed ported cast manifold I had back then never gave me a lick of trouble. Perfect sealing every time and it wasn't even that much of a pain to remove.

          Originally posted by Northern View Post
          Also I think the D610 is great, and I've been watching D600/D610 on ebay for a while because they seem like the best deal going if I want to stay Nikon.
          Go for it. D610s are good bang for the buck now. I stuck with Nikon because even though the AF lens choice is inferior to Canon, the sensors seem to be measurably better (dynamic range and SNR). Combine that with the fact that you can keep old MF lenses with Nikon vs Canon and I stuck with Nikon. I knocked Sony out of the running early on because for the same money I was going to get less camera and the secondhand lens market is worse. For the same money spent I would get a slower Sony camera with far worse battery life than the D610, and old mirrorless EVFs suck. I didn't even consider any Sony DSLRs.

          IG @turbovarg
          '91 318is, M20 turbo
          [CoTM: 4-18]
          '94 525iT slicktop, 3L M50 + BW S366 project

          Comment


            Originally posted by McGyver View Post
            Heating the metal will cause it to grow, so cylinders 3&4 will see almost no flange movement, but cylinders 1&6 will see a large lateral shift (or at least lateral forces) which could shear exhaust studs
            My (24v) rapidspool manifold was much straighter than that, maybe I got lucky?
            I think a mild convex shape to the turbine housing flange would help it seal on the sides where it would blow out. The hardware is what, M10 or M12 so I'd probably trial the turbine housing on it and see if the gap closes much? IDK

            I kind of buy the thermal expansion idea?
            If T304 has a thermal expansion coefficient of 1.6e-5, and the flange is like ~550mm long.
            Temp is hard to quantify. Sure you could get some high EGTs of like 1000degC but with the flange having a ton of surface area in contact with the head, will it even come close to half of that?
            Even if it sees something in the delta 500degC region, that's ~4.5mm across the entire flange if the flange were free to expand, so 2.25mm per end... Fitment varies, but the holes are quite O/S and there's a lot of hardware restricting it.

            I've never heard of someone snap a stud on any of these engines, so unless that or something else crazy happens with my manifold, I probably won't slice it up either.


            Edit:
            I probably will pick up a D600/610 once I'm done school, just one of many things I want but shouldn't buy right now haha
            Last edited by Northern; 03-20-2021, 11:39 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


              Maxed out my injectors this week, duty cycle in the mid 90s at 18/19psi of boost. It's still not fast enough.

              IG @turbovarg
              '91 318is, M20 turbo
              [CoTM: 4-18]
              '94 525iT slicktop, 3L M50 + BW S366 project

              Comment


                Guess it's time for bigger injectors... and an E85 conversion...

                Comment


                  E85 is a non-starter for me. Limited availability. The bigger injectors I'm working on, I have some 60lb injectors in my M42. I need to pull them and get two matching ones, then upgrade my MAP sensor so I'm not running at the ragged edge of its capabilities. Once the turbo is maxed out I'm likely done chasing more power for the E30. It honestly doesn't need any more than the 500bhp or so that turbo is good for and incredible straight line performance is the goal of my next build. Plus I'm concerned about the stock head gasket holding up with so much cylinder pressure and don't want to convert to MLS or O-ring because the head gasket is a good "fuse".

                  IG @turbovarg
                  '91 318is, M20 turbo
                  [CoTM: 4-18]
                  '94 525iT slicktop, 3L M50 + BW S366 project

                  Comment


                    Throw a knock sensor on there and setup boost/lean/knock failsafes and Oring that MF

                    If you buy the isky tool, I'd buy it from you, or pay to rent it... EDIT: nvm I own one now
                    Last edited by Northern; 12-01-2022, 02:25 PM.
                    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


                      It has been a long time since I had an update, that's probably because there was no (good) news. My car got clipped in traffic earlier this year and I've been having a hard time sourcing bumpers. Old bumpers are fragile so I don't want to ship them, and the shipping on new ones is ridiculous. Catuned wants something like $500 to ship generic replacements, Garagistic went out of stock, people want a lot of money for them locally.

                      But now there is good news. I took the E30 on a road trip. This was supposed to be an E34 trip but I didn't finish it in time, so I checked everything I could on the E30, installed an oil pressure gauge, and went for it. I took the car to Chattanooga, then to Graham county NC, home of Lake Santeetlah, the section of US129 known as the tail of the dragon, and the eastern end of the Cherohala skyway. After all of these years of having this taut E30 with a bunch of handling mods, I finally got to drive it on some great driving roads, and it handles great. The car is a pleasure to drive even without power steering.







                      Cherohala skyway was gorgeous with fresh snow in the trees and almost perfectly clear roads, it would have been impassable on my R1Rs if any snow or ice remained. Highly recommended drive, very scenic especially if there's snow and clouds.





                      Tail of the dragon was great on a cold Monday morning, I did 3 laps up and down tail of the dragon of it with my buddy (inactive) member here Shredwick, following his S2000. This was the most fun I'd had driving and the car handled great. I really wish there were some decent driving roads in Florida because this car feels at home on the mountain roads, where it's slow for drag racing and laggy for autocross.





                      I also took the car up to the top of Clingmans Dome out in the Smokies which was an atmospheric drive with the clouds, rain and fog shrouding parts of the mountain.

                      TN was a bit less driving, mostly hiking. I drove the E30 up lookout mountain (no pics, sorry), and around the raccoon mountain reservoir.


                      ​ If you go to the reservoir, do not drive a car that is lowered, stiffly sprung, or has low hanging exhaust around the drivepark road. They've put some really aggressive speed bumps on it that I had to creep over at a below walking pace and they took a toll on my forward V-band clamp which luckily survived the trip. My exhaust is banged up from this road and there is no turning back. You can't see the bumps from the entrance.

                      Unfortunately in the end, the E30 broke down on the way home, too far for a AAA tow and my best choice at the time was to tow it back with a U-haul truck. Of course the only one they had was the biggest truck they rent, and it was a long and crappy late night drive home from northern FL. It really sucked but I am thankful but my trip went off any major issues, just oil leaking and a banged up exhaust. The cause of the breakdown was the fuel pump melting down, it took one of the in-tank wires and the connector with it and was completely dead, basically open circuit. The pump was around 7 years old and as far as I can tell probably had around 70,000mi on it. As an aside, DeatschWerks are almost no help in sourcing a local replacement, I had to prod at their reps to get a partial list of FL dealers and wound up shipping one second day from Summit since I couldn't find any local companies who stocked the DW200. I hope DeatschWerks guys are reading this; I don't think I'll buy another DW pump based on how lackluster the customer service has become. I have bought several of their pumps now and have referred many people to them; they should have immediately provided me with a list of the dealers in FL so I could find try and something fast, not just quote their lead time and make me press to get 3 dealer names - none of which had what I needed. Uncool. Can no longer recommend unless their CS improves! I'll return with some photos from killboy if I decide to buy them.
                      Last edited by varg; 11-22-2022, 08:34 PM.

                      IG @turbovarg
                      '91 318is, M20 turbo
                      [CoTM: 4-18]
                      '94 525iT slicktop, 3L M50 + BW S366 project

                      Comment


                        Road tripping an E30 is great. Restores that connection and builds a better car. Sounds time to build up some travel spares. I keep an extra fuel pump, as it seems like they are all garbage.

                        You already have me excited for a week in the NC mountains for The Vintage event already.

                        Did you go out to the brodeo event?

                        I was up above it, Now I'm down in it ~ Entropy - A Build thread.
                        @Zakspeed_US

                        Comment


                          Nice to see an update, sorry to hear about the frustrations with the bumpers and pump
                          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

                          Working...
                          X