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M42 turbo pt 1- it blew up!

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    M42 turbo pt 1- it blew up!

    So wasn't planning a thread until I'd done a few more things, but times change and in addition to looking for some insight, I thought everyone would enjoy the carnage!

    So first up is the car. I've had this particular E30 in ever evolving configurations for 7 or so years.

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    Had an S52 in it for a long time and long story short I got the idea to go BMWCCA club racing, then decided specifically on D-mod with a turbo M42. Out went S52, in went M42. I haven't actually done a club race yet, as we all know life can get in the way so development of the car to get it to a point where I can go racing and be competitive has been slow. But it worked well and I do a lot of HPDEs with it (am instructor with Trillium chapter of BMW CC).

    My goal for the engine was 400-450 hp, ideally using pump gas for the convenience, but ethanol would also be acceptable (and more realistic). Race gas is out of the question (and a big factor in why I chose d-mod and not s54/cmod).

    So for some current specs

    -M42, complete stock internals.
    -Garrett GT3071r 86ar .90 trim
    -MLS gasket (oem thickness), ARP head studs.
    -eBay m44 bottom mount turbo manifold flipped around, modified and pedestal built for fitment.
    -42lbs injectors
    -eBay intercooler, BOV
    -VEMS ecu

    I'm aware that I will not reach my power or reliability goals with what I listed. More on that later.

    So now for the bit that leads this thread. I've been running with setup I listed above for about 2 years. Overall engine has been extremely reliable and very fun. I've never been to a dyno, just "tuned" on the fly with logs and AFRs. Pushing 17lbs of boost, my butt dyno and drag races up the Andretti straight at Mosport tells me I have somewhere between 250 and 300hp.

    Among my many winter projects, I picked a few more upgrades that would inch me ever closer to my goal. I always felt like the intake was a bit restrictive and that stock throttle body was crap so those are what I addressed. Did some maths, decided on a 3" throttle body, and upgraded my intercooler.

    My old intercooler vs the upgrade. Mishimoto says this size is good for up to 350-500hp.

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    So this past weekend had the car out at Mosport for the first time this year. I didn't make any changes to the tuning from last year, but holy crap the car felt amazing, completely different from last year. The throttle response was unbelievable and the lag I used to have at 3500rpm was gone. How much of that was from the less restrictive intake and how much of that was from the getrag 260 to ZF swap I don't know, but man was the car alive!

    As the saying goes, engines always run best before they blow and about 5 minutes into the very first session of the day... KABOOM!
    Last edited by Dissembler; 05-04-2018, 06:20 PM. Reason: BMW CC

    #2
    Full throttle, heading up the hill to turn 4, just shy of 7000 rpm and there is a huge noise. Car loses power, debris is flying everywhere, smoke... all that good stuff when an engine blows. It happened without warning too, no misfires, knocking, loss of power, nothing.

    The engine was still running after it all blew! Actually had to flip the ignition to shut it down lol. So engine is now out of the car, pulled the head off and this what I've found. Cyl 4 decided it no longer want to be part of the engine. the block has holes on both sides, the coolant jackets around the cyl was hit and the oil pan was destroyed.

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    Crazy part is, the cyl head is completely intact, the cylinder bore is completey intact (no scratches or anything), the crank and connecting rod bearings showed zero sign of damage and an inspection of the plug shows no issues or signs of being lean. Connecting rod looks almost like it had a clean break, edges just got smooshed a little from hitting the block. What do you guys think?

    So for now the plan is this: A set of schrick cams (256/256) and valve springs just arrived from VAC. going to swap those into my currently stock spare m42 (plus mls gasket and studs), boost will be turned down to 14psi, then hit the dyno for some proper tuning and enjoy the rest of the year. Got some plans to travel to a few different tracks and don't want to have engine blow away from home. Bought 1000cc injectors and a big fuel pump already, pistons and connecting rods will come next year and then I'll shoot for that 450hp and see what happens!
    Last edited by Dissembler; 05-04-2018, 06:25 PM.

    Comment


      #3
      When you say you revised the intake, are you talking about your pre-turbo inlet? Were you always recirculating the crank case breather to your turbo inlet like that in your previous setup too?

      I think it's rad that you're tracking a turbo m42. Props!
      You have more courage making power on an m42 than I have on my m20 turbo since I'll be tracking it soon lol.

      1991 325iS turbo

      Comment


        #4
        Holy crap two years running 17 psi on that GT3071R?!?! That's a pretty big turbo and a decent amount of air in that engine. I'm impressed it has lasted so long. I personally had detonation issues on my stock M42 with a small T25 turbo on track probably due to intake temperatures and too much ignition timing. But all that seemed to happen to my engine is probably a cracked piston ring, small detonation marks on the pistons, and lots of engine blow by.

        If I were you I would be trying to drop the compression a bit on the engine maybe even down to 9:1 I find it hard to believe you weren't having detonation problems with such high boost on a decently sized turbo on pump gas with 10:1 compression.

        I think you should toss another stock engine in and run lower boost this year. Then start to build a forged bottom end rods, low compression pistons, ect. build a nice head with those valve springs and cams then shoot for a 400whp M42 I think that'll be super rad.
        -Dee
        5-lugged turbo 318is Barn car
        IG: @deebelmont

        Comment


          #5
          That's incredible! How did a stock M42 survive that?! I'm working on a much more modest build, but I'm also dropping the CR to around 9:1. What's your cooling system setup?

          Comment


            #6
            Thanks for the props! I get a lot of people asking me what I have in it and they are always very surprised to learn its wee little four banger lol

            Originally posted by ak- View Post
            When you say you revised the intake, are you talking about your pre-turbo inlet? Were you always recirculating the crank case breather to your turbo inlet like that in your previous setup too?
            Crank breather was always like that. The changes to my intake were the new intercooler and bigger throttle body. The ebay intercooler only had 2" in/out, the new mishimoto has 2.5" in/out. Then the 3" throttle body has an area of 7" vs under 5" for the stock throttle body.

            Originally posted by ccsdo5 View Post
            Holy crap two years running 17 psi on that GT3071R?!?! That's a pretty big turbo and a decent amount of air in that engine. I'm impressed it has lasted so long. I personally had detonation issues on my stock M42 with a small T25 turbo on track probably due to intake temperatures and too much ignition timing. But all that seemed to happen to my engine is probably a cracked piston ring, small detonation marks on the pistons, and lots of engine blow by.
            So for the first bit of 2016, I only ran 8psi while I figured out VEMS and got the fuel and igniton tables sorted out. My ignition advance is very conservative, only 22deg IIRC. Once I got the engine running good after the first few times out I bumped the boost to 12psi. Winter 2017, I befriended someone who knows a lot more about tuning than I do. We turned the boost up to 17psi and corrected some issues with my maps. I didn't change much after that except play with the waste gate solenoid to get quicker spooling. In total I think I had about 70 or 80 hours of on-track time for 2017.

            The engine has never knocked or misfired. I think one of the big factors in it running so well is that it stays very cool. Even on 35C (95F), intake temps would never get over 50C and coolant temps never over 95C. For reference, the s52 would regularly run around 115C.

            I'll be able to post some more pictures of various things tomorrow

            Comment


              #7
              Originally posted by jwal View Post
              That's incredible! How did a stock M42 survive that?! I'm working on a much more modest build, but I'm also dropping the CR to around 9:1. What's your cooling system setup?
              It is a stout little motor, I think if I'd gotten to the dyno before this happened it never would have happened at all but thems the breaks.

              So the rad is an E36 mishimoto, I got rid of the stock oil filter, fitted a BAT motorsports take off plate. Remote mounted a pf16 type oil filter and have a 25000btu oil cooler. Everything is mounted as far forward as it can go and the setup is ducted right through the hood (see the big hole in the first pic with car)

              Comment


                #8
                Preignition probably. No idea how loud your exhaust is but the appearance of the car screams "I'm really loud" and you even if you hear it you may be too late. Sure it's a fairly strong engine when everything is right but a couple of enormous cylinder pressure spikes due to preignition will crush that stock bottom end like nothing. Running hard on a track, big turbo, everything in the combustion chambers getting very hot, revving to 7,000rpm, not really a big surprise that it let go.

                What was your injector duty cycle at full boost? 42lb seems too small to me. I was running 60lb injectors in my turbo M42, and pushing 18psi (T3/T04E 50 trim).
                Last edited by varg; 05-06-2018, 07:07 PM.
                @turbovarg
                '91 318is, M20B25, T3/T04E 60 trim (18psi), megasquirt, coilovers, Z3 rack, cold AC
                [b u i l d]
                [Car of the month: April 2018]

                0c8b7c9527af628a346878feb14bf757

                Comment


                  #9
                  Sweet build, any more detail on the throttle body and where you got that adapter piece?

                  In works on my own turbo m42 (bottom mount)
                  318iS Track Rat :nice: www.drive4corners.com
                  '86 325iX 3.1 Stroker Turbo '86 S38B36 325

                  No one makes this car anymore. The government won't allow them, normal people won't buy them. So it's up to us: the freaks, the weirdos, the informed. To buy them, to appreciate them, and most importantly, to drive them.

                  Comment


                    #10
                    I'm interested in that as well. I don't think the M42 TB is good for much past stock. Couldn't an M50/52 TB be used with an adapter?

                    Comment


                      #11
                      nice carnage op. for those interested in a Tb alternative m50 single plate body plugs right in and all you need is to fabricate an adapter.

                      Turbo M42 Build Thread :Here
                      Ig:ryno_pzk
                      I like the tuna here.
                      Originally posted by lambo
                      Buttchug. The official poster child of r3v.

                      Comment


                        #12
                        Originally posted by downforce22 View Post
                        Sweet build, any more detail on the throttle body and where you got that adapter piece?

                        In works on my own turbo m42 (bottom mount)
                        Got the throttle body from the wreckers, its a 75mm unit that comes on all Ford 4.6Ls. The adapter is just something I made. I had 1/4" steel plate lying around. Traced the gaskets as a template to make flanges and used the plasma cutter to cut it out. Then took some 3" exhaust pipe, cut it open, welded it to the flanges than made pieces that filled in the gaps. Stock throttle cables works with it too, just have to cut a small slot for the end of it and I made a bracket to support the cable relative to the throttle body. There is a hole drilled in the throttle plate for idle which actually works nearly perfectly. I don't have an idle air controller and it idled around 950rpm.
                        Last edited by Dissembler; 05-07-2018, 07:03 PM.

                        Comment


                          #13
                          Originally posted by varg View Post
                          Preignition probably. No idea how loud your exhaust is but the appearance of the car screams "I'm really loud" and you even if you hear it you may be too late. Sure it's a fairly strong engine when everything is right but a couple of enormous cylinder pressure spikes due to preignition will crush that stock bottom end like nothing. Running hard on a track, big turbo, everything in the combustion chambers getting very hot, revving to 7,000rpm, not really a big surprise that it let go.

                          What was your injector duty cycle at full boost? 42lb seems too small to me. I was running 60lb injectors in my turbo M42, and pushing 18psi (T3/T04E 50 trim).
                          Surprisingly not as loud as you'd imagine. 3" exhaust, single borla muffler at the back that does quite a bit to quiet things down. Calabogie and Tremblant have very strict dba limits and I haven't had to add a second muffler to meet them.

                          Maybe pre ignition, but you'd think with enough preignition to crack a piston/break a con rod into 3 pieces there would be signs of it elsewhere?

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                          I should add that white lines that look like cracks is actually dog hair lol. Have 2 huskies and that stuff gets everywhere even when they're no where around!

                          In other news, got another engine and am prepping it to go in

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                          and finally got these away from UPS... stupid UPS. I ordered these back in end of february from VAC and they just arrived because the keepers were back ordered. Was supposed to have them in march and they were what I was waiting for before taking the car to they dyno. Got 1000cc injector clinic injectors and a FiTech surge tank/pump combo that will be going in too.

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                          Last edited by Dissembler; 05-07-2018, 07:13 PM. Reason: moar information

                          Comment


                            #14
                            OP, are you using only original early M42 parts or do you mix and match with e36 components?

                            I'm trying to build my motor with the best of both worlds, and I still haven't determined which platform would be best for cost effective tuning. I have one of every form of the M4x motors. E30 M42, E36 M42, and M44.

                            Comment


                              #15
                              The engines I have are E30. If I could find a few M44s I would probably go that route because of of the knock sensors and the chain idler is replaced with a rail

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