• BMW puts the S55B30 motor on display in Detroit - 425 horsepower, 406 pound-feet of torque plus compression ratio, redline, boost, bore x stroke specifications

      Ok BMW, this was pretty cool of you to do at the NAIAS (North American International Auto Show). Say hello to the S55B30, the motor that will be powering the upcoming F80 M3 and F82 M4. BMW already showed many of these details in a press release on the engine last year but real life photos of a motor that will be a staple in BMW tuning for years to come and specifications never hurt. As a reminder, the 3.0 liter direct injected twin turbo inline-6 has 430 horsepower and 406 pound-feet of torque (more than the previously reported 369).


      The engine is also 22 pounds lighter than the S65 V8 and this is with fluids. The total engine weight is 452 pounds. The engine also revs to 7600 rpm. The compression ratio is a fairly high 10.2:1 and the same as the N55 inline-6 that sees duty in the 335i.

      It is interesting to note that the bore and stroke are 89.6mm and 84.0mm respectively. Compare this to the bore and stroke of the N55 inline-6 which is at 84.0mm and 89.6mm respectively. That is not a typo, the N55 and S55 share the exact same 2,979 cc displacement although their bore and stroke figures are reversed.

      BMW designed the S55 oversquare giving a bore to stroke ratio that is greater than 1:1. This allows for lower piston speeds at higher revs. The S55 develops its peak torque as early as 1850 rpm and maintains it until 5500 rpm meaning the oversquare design has not hurt the low end much (although the N55 hits peak torque earlier) and BMW has done a good job balancing high RPM power and low end punch.

      BMW's turbochargers are produced by Honeywell and generate 1.25 bar (18.12 psi) of boost. Will there be room to push the turbos past this level? Most certainly. The question will be by how much.

      The downsides? The fuel tank is only 15.8 gallons. Why BMW continues to give their M3's such small fuel tanks is anyone's guess.

      Enjoy the photos below.

      S55B30
      DISPLACEMENT (CC): 2,979
      BLOCK/HEAD MATERIAL: ALUMINUM/ALUMINUM
      BORE STROKE (MM): 89.6mm 84.0mm
      HORSEPOWER (SAE NET): 425 @ 7,300 RPM
      TORQUE: 406 LB.-FT. @ 1,850 - 5,500 RPM
      SPECIFIC OUTPUT: 141.6 HP/L
      COMPRESSION RATIO: 10.2:1

























      This article was originally published in forum thread: BMW puts the S55B30 motor on display in Detroit - 425 horsepower, 406 pound-feet of torque plus compression ratio, redline, boost, bore x stroke specifications started by Sticky View original post
      Comments 83 Comments
      1. Sticky's Avatar
        Sticky -
        Holy crap it's 6 AM. I didn't even finish everything I wanted to write...
      1. Itsbrokeagain's Avatar
        Itsbrokeagain -
        Love it. Have high expectations for this one. Cast exhaust manifolds?
      1. mjmarovi's Avatar
        mjmarovi -
        2jzClick here to enlarge
      1. lulz_m3's Avatar
        lulz_m3 -
        I wonder if that front turbo inlet tube would fit the N54...
      1. MisterEm's Avatar
        MisterEm -
        Yum.

        Should be a fun run with this M model.
      1. 5soko's Avatar
        5soko -
        Hope the fuel pump and direct fuel injectors have been worked out well on this engine.
      1. mjmarovi's Avatar
        mjmarovi -
        Click here to enlarge Originally Posted by 5soko Click here to enlarge
        Hope the fuel pump and direct fuel injectors have been worked out well on this engine.
        With any luck BMW fixed N54 HPFP issue for us...but I doubt it....
      1. BuraQ's Avatar
        BuraQ -
        Good luck trying to upgrade that AWIC or even doing a turbo upgrade on this thing. Looks like Dinan will more likely be the first vendor to come out with a AWIC upgrade for the S55 though, pretty sure about that. However, for a little bigger core, they are going to rape you like hell on the price tag.

        I think the M235i will be mush more mod friendly than the M3/M4
      1. BMWJunkie's Avatar
        BMWJunkie -
        Nice to see they ditched the electric water pump.

        Lets see some pics of the hpfp.
      1. VargasTurboTech's Avatar
        VargasTurboTech -
        Click here to enlarge Originally Posted by BMWJunkie Click here to enlarge
        Nice to see they ditched the electric water pump.

        Lets see some pics of the hpfp.
        Already know what the HPFP looks like. Just look at the latest N55 pump. They converted the housing that used the rotational pump so it would accept a traditional style cam driven pump. All those parts are available right now if you want to give them a shot, we almost did it, but decided against it.
      1. VargasTurboTech's Avatar
        VargasTurboTech -
        Click here to enlarge Originally Posted by BuraQ Click here to enlarge
        Good luck trying to upgrade that AWIC or even doing a turbo upgrade on this thing. Looks like Dinan will more likely be the first vendor to come out with a AWIC upgrade for the S55 though, pretty sure about that. However, for a little bigger core, they are going to rape you like hell on the price tag.

        I think the M235i will be mush more mod friendly than the M3/M4
        Why do you say that? AWIC's are super common and easy to upgrade we have been running them for decades, spearco prob has a much better flowing core that will fit right in there, get some better flowing ends either cast or fabricated and you have an upgraded AWIC.
      1. rt turbo's Avatar
        rt turbo -
        has anyone seen anything more specific on the internal metalurgy specifications? Are pistons/rods/crank all forged? Also, never understood why so many oems put plastic end tanks on intercoolers. I wasnt expecting an air to water intercooler though.
      1. rt turbo's Avatar
        rt turbo -
        Click here to enlarge Originally Posted by BuraQ Click here to enlarge
        Good luck trying to upgrade that AWIC or even doing a turbo upgrade on this thing. Looks like Dinan will more likely be the first vendor to come out with a AWIC upgrade for the S55 though, pretty sure about that. However, for a little bigger core, they are going to rape you like hell on the price tag.

        I think the M235i will be mush more mod friendly than the M3/M4
        I dont think that upgrade will be a bad one. You can get almost any size awic now days and BMW has done the hard part of integrating it into the coolant system.
      1. VargasTurboTech's Avatar
        VargasTurboTech -
        Click here to enlarge Originally Posted by rt turbo Click here to enlarge
        I dont think that upgrade will be a bad one. You can get almost any size awic now days and BMW has done the hard part of integrating it into the coolant system.
        I think running the engine coolant through it is also part of the what needs to be changed, these engines run very high water temps, and getting rid of that and running a dedicated coolant supply for the AWIC will net much lower IAT's. What good is running 210 degree water through a heat exchanger thats trying to cool off a less than 200 degree Air temps. I think there was a MB platform running an AWIC and this was part of the upgrade, getting it out of the cooling system loop.

        Edit: The more I look the more it appears BMW was smarter than running the coolant through the AWIC. That coolant tank the IC is connected to near the firewall looks much too small for the entire engine, the IC system most likely has its own coolant system, including heat exchanger, and pump.
      1. Eleventeen's Avatar
        Eleventeen -
        Click here to enlarge Originally Posted by VargasTurboTech Click here to enlarge
        I think running the engine coolant through it is also part of the what needs to be changed, these engines run very high water temps, and getting rid of that and running a dedicated coolant supply for the AWIC will net much lower IAT's. What good is running 210 degree water through a heat exchanger thats trying to cool off a less than 200 degree Air temps. I think there was a MB platform running an AWIC and this was part of the upgrade, getting it out of the cooling system loop.

        Edit: The more I look the more it appears BMW was smarter than running the coolant through the AWIC. That coolant tank the IC is connected to near the firewall looks much too small for the entire engine, the IC system most likely has its own coolant system, including heat exchanger, and pump.
        Yes, all fo the 32 and 55 series Kompressor motors circulate the same engine coolant throught the AWIC. However, they did at least have a separate heat exchanger that the water flowed through before going to the AWIC (from the factory). That brought the water temp way down compared to the ECT.

        On my C32 AMG I took that a step further. I moved my battery to the trunk and replaced it with a water tank that mounted in the battery tray, then separated the water circuit. It was made to fit an 03-04 Cobra, but I adapted it to work.
      1. Eleventeen's Avatar
        Eleventeen -
        Shhhhh, if you listen really closely, you can hear the wastegates rattling in picture #2 .
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by rt turbo Click here to enlarge
        has anyone seen anything more specific on the internal metalurgy specifications? Are pistons/rods/crank all forged? Also, never understood why so many oems put plastic end tanks on intercoolers. I wasnt expecting an air to water intercooler though.
        The crank is forged. The cylinders are lined.

        Check this link out: http://www.bimmerboost.com/content.p...l-transmission

        I don't know about the pistons or rods. I think the rods are forged and the pistons are likely cast with a coating of some sort.

        This is the piston. I can't tell if it's forged or not but some guys here can:

        Click here to enlarge
      1. THATDONFC's Avatar
        THATDONFC -
        It makes sense BMW went with A2L coolers. They're dual pass too. Looks like a promising platform. I'd be interested in seeing the heat exchanger(s).
      1. Sticky's Avatar
        Sticky -
        Watch BMW fixes absolutely everything that anyone could possibly want with the direct injected turbo motors and gives the turbos plenty of headroom but makes the ECU uncrackable. It would be such a cruel joke.
      1. andrew20195's Avatar
        andrew20195 -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        makes the ECU uncrackable
        No such thing. All it takes is talent, or the money to hire it. And I'm willing to bet there will be plenty of money in that market.

        Interesting to note, it looks like the wastegates are purely electronic. No vacuum connections. Aside from allowing BMW complete control over when and how much they open, I assume it will also allow them more data on wastegate performance and mod detection.