• PPM-Racing (Pure Performance Motorsport) 4.2 liter S38 inline-6 stroker kit - $6900

      The BMW S38 is one of (if not arguably the best) the most impressive inline-6 cylinder motors ever produced by BMW. We will leave that debate for another article however and instead give you the details on the PPM-Racing 4.2 liter stroker kit. It includes forged pistons, H-Beam connecting rods, and a billet 4340 crankshaft. It is applicable to either 3.6 or 3.8 liter S38 motors from the BMW E28 M5 and BMW E34 BMW M5 respectively.

      The kit can be customized and accommodate naturally aspirated or boosted builds with compression ratio choices for the pistons including 8.0:1, 8.5:1, 10.0:1, 11.5:1, or 12.0:1. Piston sizes are either 94.5 or 95.0 mm. The kit is designed to use a 1x compression ring. Awesome? Yes, awesome.

      Pricing: $6900

      Included:

      - 6x forged pistons
      - Rings, pins, locks
      - 6x H-Beam connecting rods
      - ARP2000 rod bolts
      - 98mm Billet 4340 crankshaft





      This article was originally published in forum thread: PPM-Racing (Pure Performance Motorsport) 4.2 liter S38 inline-6 stroker kit - $6900 started by Sticky View original post
      Comments 60 Comments
      1. fundahl's Avatar
        fundahl -
        Click here to enlarge Originally Posted by GG///M3 Click here to enlarge
        I vote 8.5.1 turbo setup with a gtx42 turbo redline at a safe 8200 rpms. That thing would have a monster powerband.
        I'm right there with you brotha! None of this weak NA nonsense. Click here to enlarge
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by Tom S85B58 Click here to enlarge
        Yes i am sure with billet crank and ppm custom S38 balancer the problem was fixedClick here to enlarge

        S85B58? You have a stroker or just a fan?

        How do you know this does not have high RPM issues?
      1. radasaurus's Avatar
        radasaurus -
        Click here to enlarge Originally Posted by Tom S85B58 Click here to enlarge
        Yes i am sure with billet crank and ppm custom S38 balancer the problem was fixedClick here to enlarge
        I doubt the problem is fixed...it is a matter mostly of the geometry of the crank, not so much the material it's made from. A custom damper would help, but it would probably not solve the "problem".
        I don't think its too much of a problem though, monster torque with a redline 7-7.5k should provide a pretty awesome power band and longevity.
      1. DBFIU's Avatar
        DBFIU -
        You are all wrong and my opinion is better.
      1. GG///M3's Avatar
        GG///M3 -
        Click here to enlarge Originally Posted by SlicktopTTZ Click here to enlarge
        I'm right there with you brotha! None of this weak NA nonsense. Click here to enlarge
        Yes who gives a crap about N/A? Not even BMW any more. Click here to enlarge
      1. fundahl's Avatar
        fundahl -
        Click here to enlarge Originally Posted by GG///M3 Click here to enlarge
        Yes who gives a crap about N/A? Not even BMW any more. Click here to enlarge
        Click here to enlarge
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by GG///M3 Click here to enlarge
        Yes who gives a crap about N/A? Not even BMW any more. Click here to enlarge
        That does not mean NA is bad.

        A stroked s38 like this fits the e30 character more. The chassis doesn't need 1000 whp.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by LostMarine Click here to enlarge
        Any power figures?
        It depends on the chosen setup...
      1. GG///M3's Avatar
        GG///M3 -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        That does not mean NA is bad.

        A stroked s38 like this fits the e30 character more. The chassis doesn't need 1000 whp.
        E30 is played in my eyes. There are a million people who have done the e30 thing
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by GG///M3 Click here to enlarge
        E30 is played in my eyes. There are a million people who have done the e30 thing
        Who cares? The point is some cars don't need some absurd amount of turbo power. The E30 is one of them IMO. It would be plenty entertaining with an NA motor like this S38 at 4.2 with 12.0:1 comp pistons.
      1. fundahl's Avatar
        fundahl -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        Who cares? The point is some cars don't need some absurd amount of turbo power. The E30 is one of them IMO. It would be plenty entertaining with an NA motor like this S38 at 4.2 with 12.0:1 comp pistons.
        I still like the turbo S14 idea for the e30 M3. Would love that. Otherwise a fully opened up S85 would be insane in that thing.... that would be great NA power! Wonder how much of the M5 drive-train you could stuff in there....
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by SlicktopTTZ Click here to enlarge
        I still like the turbo S14 idea for the e30 M3. Would love that. Otherwise a fully opened up S85 would be insane in that thing.... that would be great NA power! Wonder how much of the M5 drive-train you could stuff in there....
        @Apex Speed Technology did the V10 in an E30... Here: http://www.vwboost.com/showthread.ph...ed-Technology!
      1. fundahl's Avatar
        fundahl -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        That's just exactly what I wanted to see. So much Win!
      1. dreikraft's Avatar
        dreikraft -
        you got the wheels turning.

        been a while since i played with NA....
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by radasaurus Click here to enlarge
        Even the s54, which was designed for high rpms, suffers when pushed much beyond its stock redline. The s38's harmonic damper is not as robust (especially in the b35 and b36 versions) nor is it designed for the same rpm range.
        Click here to enlarge Originally Posted by radasaurus Click here to enlarge
        Even the s54, which was designed for high rpms, suffers when pushed much beyond its stock redline. The s38's harmonic damper is not as robust (especially in the b35 and b36 versions) nor is it designed for the same rpm range.
        You are right, and the long cams pose a problem at high RPM but from what I know about the S38 it is regularly revved to 7500 with mild tunes stock without issue and has seen 8k. This is all stock internals. So is 8500 on aftermarkets all that big of an issue considering BMW made the S14 crank capable of 10000 rpm and kept it at 7000?
      1. JAWS Motorsport's Avatar
        JAWS Motorsport -
        I hope you did the new stroker crank like the S38B38 and not the S38B36, since the B36 and all B30 for that mather had problems on revs...loosing that 410Nm crank bolt allt the time, it didnt get better when boosted! , S38 crank is MUCH better designed with its hub/damper.

        Attachment 17669
      1. Tom S85B58's Avatar
        Tom S85B58 -
        Click here to enlarge Originally Posted by JAWS Motorsport Click here to enlarge
        I hope you did the new stroker crank like the S38B38 and not the S38B36, since the B36 and all B30 for that mather had problems on revs...loosing that 410Nm crank bolt allt the time, it didnt get better when boosted! , S38 crank is MUCH better designed with its hub/damper.

        Attachment 17669


        Hmm this is the first i ever heard of this problem, I know many guys with S38B36 race engines and i ask them about this, and they all said the same thing newer had issues with the Long Bolt set up in the S38B36. Maybe it was the case on few engines due to wrongly torqued bolt?

        Also all S14B25 Evo's use this long bolt set up and they turn their Race Engines to 9400RPM without any problems.
      1. Tom S85B58's Avatar
        Tom S85B58 -
        Click here to enlarge Originally Posted by radasaurus Click here to enlarge
        what the $#@! is that supposed to mean? The fact is its a VERY long stroke crank on a straight six that has harmonic issues past 7k with the stock crank. I am not denigrating the kit or the idea of an 8.5k rpm 4.2L s38 screamer (which would be awesome), but it's a pipe dream.

        I did some digging Click here to enlarge PPM 95/98mm 4.2l Stroker kit is much lighter then the OEM S38B36 crankshaft,rods,pistons! So the reciprocating weight is less then OEM S38B36 with the huge extra stroke!
        Also the Crankshaft is Billet, Rods are forged,Pistons are forged so the kit is more durable then OEM parts. PPM Looked at the harmonics as well, and Ross/PPM Balancer was designed and made to tangle this issue as well. So what i can see all the possible problems where take into-count when this kit was designed for the passionate N/A RacersClick here to enlarge
      1. JAWS Motorsport's Avatar
        JAWS Motorsport -
        Click here to enlarge Originally Posted by Tom S85B58 Click here to enlarge
        Hmm this is the first i ever heard of this problem, I know many guys with S38B36 race engines and i ask them about this, and they all said the same thing newer had issues with the Long Bolt set up in the S38B36. Maybe it was the case on few engines due to wrongly torqued bolt?

        Also all S14B25 Evo's use this long bolt set up and they turn their Race Engines to 9400RPM without any problems.
        Its actually the hub that walks on the crank, finally it damages the "woodruf key" that locks the hub in position, my experience are on turbocharged high tourqe engines, but i guess BMW re-designed when making the B38 of a reason? I hope PPMīs stuff works good bcs its a nice upgrade to a super nice engine.

        Attachment 17721
      1. Sticky's Avatar
        Sticky -
        Sounds like starting with a B38 is the best way to go.