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Any advice before I jump in? Head port, 2 piece header, 48mm TB

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  • Any advice before I jump in? Head port, 2 piece header, 48mm TB

    I'm planning an engine project this winter and want to get some input before I precede. Just wondering if anyone has some advice that will save me some time, money, mistakes, etc.

    I have 1990 M3. It's primary a street car that sees some track time.

    I'm running a 2.5L engine with about 10,000 miles (and a few years) on it since the rebuild. I am running 11.0 compression, 292/284 cams, a stage one VAC head rework, and am running alpha-n via Megasquirt. I am planning to get the head ported and will be pulling the head myself. This will be my first time pulling a head off of ANY engine. FYI, I had a local shop do the 2.5L rebuild. I wish I'd just had the head ported during the original rebuild, but the cost were getting out of hand.

    I also have 48mm throttle bodies and a 50/50, two piece header to install. I plan to install these when I am reinstalling the head. I'd love to install the header and TB separately, before I port the head, but I just don't thing I can justify the extra effort. I would like to install the exhaust, re-tune the MS to quantify performance gains, then do the same thing for the TBs. Problem being that I'd duplicate this work when I pulled the head. MAYBE I'd be satisfied with the performance improvements after the initial upgrades, but I doubt it. The info I'd learn and share with the forum would be beneficial, but I'm skeptical I'd be enlightening enough to justify the extra work. Feel free to convince me otherwise. That's part of the reason I'm posting.

    Anyway, I'm mainly looking for advice that will help prevent some blatant screw ups or regrets that I didn't do a particular service/upgrade during the project.

    I have searched (and read) the forum for head pulling threads. I do have access to online BMW torque values. I have (and have read) a Chilton manual that will be a bit helpful. I'm grateful to BMW and forum members for providing the BMW service manual and illustrated parts catalog. These will be very helpful.

    FYI, I have done a moderate amount of work on the car myself. Just nothing like involving engine internals. I built and installed the MS myself. I've pulled the TBs to replace the blocked rubber gaskets, replaced starters, pulled radiators. Of course I've done quite a pit of normal maintenance like brakes, hose replacement, rebuilding the shifter linkage among other things.

    Finally, if anyone is in the Northwest Arkansas area and whats to help out, please speak up!

    Thanks in advance

  • #2
    Have you dynoed your current setup? Would be good to have a baseline before doing your mods.
    Several E30 M3's.

    More than I need but not as many as I want....

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    • #3
      I have dynoed the car, but there was a problem. I didn't know it at the time, but the timing wheel on the crank pulley had slipped. This retarded my timing. So I'm not confident in the numbers, but they do give me an idea what power I was making.

      I also have a G-Tech that can estimate horsepower. This unit isn't perfect, but I think it is good enough to do before and after comparisons, caveats being that you do numerous runs and that you take the results with a grain of salt. Well you'd also need to only compare runs from days with similar weather and all the other normal dyno comparison caveats.

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      • #4
        who is going to do your head porting?


        www.JOEBMWMotorsport.com
        JOEBMWMotorsport
        E30 M3 Rebuild Thread
        BMW & E30 M3 Parts and Services Specialist

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        • #5
          I'm not 100% decided, but Bavarian Solutions is a top contender.

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          • #6
            Originally posted by indie_wannabe View Post
            I have dynoed the car, but there was a problem. I didn't know it at the time, but the timing wheel on the crank pulley had slipped. This retarded my timing. So I'm not confident in the numbers, but they do give me an idea what power I was making.

            I also have a G-Tech that can estimate horsepower. This unit isn't perfect, but I think it is good enough to do before and after comparisons, caveats being that you do numerous runs and that you take the results with a grain of salt. Well you'd also need to only compare runs from days with similar weather and all the other normal dyno comparison caveats.
            A dynojet, if kept in good condition and well maintained will give you pretty consistent readings and takes into account temperature, humidity and barometer pressure. I'd recommend finding a good one that you can use as a tool to determine the effects of the various changes. I've done this and it has helped me to assess the benefits or lack thereof with changes to the motor.

            A G-tech is or butt dyno is not really a good tool if you want to quantify the results. Especially when you're looking for overall improvements, not just peak HP gains.
            Several E30 M3's.

            More than I need but not as many as I want....

            Comment


            • #7
              sell the 48s, save the $$ from the head job and use it all for track days and beer lol ........ then build from there.

              a M3 with your engine specs ALREADY seems like one beastly machine. I know because my megasquirt unleashed the devil inside that S14 and im just at 2.3 with a 264.

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