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    • 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 -
        Click here to enlarge Originally Posted by andrew20195 Click here to enlarge
        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.
        I was joking but it would be a cruel twist.

        BMW has not exactly been mod friendly. Always amuses me how they push their most hardcore fans away.
      1. BuraQ's Avatar
        BuraQ -
        Click here to enlarge Originally Posted by VargasTurboTech Click here to enlarge
        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.
        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.
        The AWIC of the S55 is on the top of Engine with barely any room. Yea sure you can upgrade to the "heat exchanger" but trying to upgrade to a bigger AWIC how do you suppose it will fit without altering the hood ?

        I am talking about a direct replacement without having to do any replumbing
      1. benzy89's Avatar
        benzy89 -
        The fact that this is the first M3 to come FI from the factory will definitely bring a LOT of high profile aftermarket tuners that the M3 did not previously have. Besides the wide selection of established BMW tuners (Active Autowerke, BMS, COBB, Evolve, ESS, Gintani), I'd expect some well known (and respected) turbo tuners like AMS + Switzer to both dump a TON of R&D into this car.


        Expect a similar progression/growth that the N54 and S63 Tu are going through.... It'll start with basic piggyback boost modifiers, bolt-ons, and then after cracking the DME slowly easy it's way into flash tuning, turbo upgrades, etc etc.
      1. BuraQ's Avatar
        BuraQ -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        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.
        LMAO ! Damn bro you spoke what is pondering in my mind.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by BuraQ Click here to enlarge
        The AWIC of the S55 is on the top of Engine with barely any room.
        Why can't you move it?

        Also, I believe the hood bulge serves a function this time around as far as clearance for the IC. There is no reason you can't upgrade it.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by benzy89 Click here to enlarge
        The fact that this is the first M3 to come FI from the factory will definitely bring a LOT of high profile aftermarket tuners that the M3 did not previously have. Besides the wide selection of established BMW tuners (Active Autowerke, BMS, COBB, Evolve, ESS, Gintani), I'd expect some well known (and respected) turbo tuners like AMS + Switzer to both dump a TON of R&D into this car.


        Expect a similar progression/growth that the N54 and S63 Tu are going through.... It'll start with basic piggyback boost modifiers, bolt-ons, and then after cracking the DME slowly easy it's way into flash tuning, turbo upgrades, etc etc.
        Good. The more the merrier.
      1. BuraQ's Avatar
        BuraQ -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        Why can't you move it?

        Also, I believe the hood bulge serves a function this time around as far as clearance for the IC. There is no reason you can't upgrade it.
        Never said you couldn't, it just would not be a direct replacement. As for the hood hump, hopefully the factory didn't rob that space completely
      1. Ging's Avatar
        Ging -
        anyone else see it looks like a 8 rib belt running the A/C and Alt. Why so much belt??
      1. rt turbo's Avatar
        rt turbo -
        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.
        Right, agreed. I was meaning its own cooling setup and heat exchanger.
      1. Mr.335's Avatar
        Mr.335 -
        For the amount of money this car will cost, why did they chose to go with a plastic IM not understanding the reasoning behind this.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by Mr.335 Click here to enlarge
        For the amount of money this car will cost, why did they chose to go with a plastic IM not understanding the reasoning behind this.
        BMW would make plastic pistons if they could get away with it.
      1. IMHOWTFFTW's Avatar
        IMHOWTFFTW -
        Yep, just read this. http://www.tcbmw.com/wp-content/uplo...-M4-Retail.pdf . If I packaged a M3/4 equal to my 2010 or 2013 E92 the F8x is over $100k! Vette.....
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by IMHOWTFFTW Click here to enlarge
        Yep, just read this. http://www.tcbmw.com/wp-content/uplo...-M4-Retail.pdf . If I packaged a M3/4 equal to my 2010 or 2013 E92 the F8x is over $100k! Vette.....
        Canadian pricing about $10k higher than US.
      1. Mr.335's Avatar
        Mr.335 -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        BMW would make plastic pistons if they could get away with it.
        LOL..such a shame.
      1. fastgti69's Avatar
        fastgti69 -
        Click here to enlarge Originally Posted by Mr.335 Click here to enlarge
        For the amount of money this car will cost, why did they chose to go with a plastic IM not understanding the reasoning behind this.
        I remember asking Arin@APR this about 5 years ago with my GTI engine. On why they'd never come out with an aluminum Intake mani instead of plastic cheap etc.

        His response obviously not verbatim but still made a good point was that plastic is much better with heat. There is no heat soak in plastic like there is with aluminum. Then there are the cons that it is cheap, and can break easier than aluminum of course.

        I haven't really seen them break at all really, (VW intake manifolds or even our own N54 intake manifolds). Most things that break are plastic chargepipes and plastic end tanks on the intercooler.
      1. Flinchy's Avatar
        Flinchy -
        somehow this whole time i missed that they didn't bump it up to 3.2L

        this makes me super sad.

        and 15.8 gallons of fuel is small on what planet?

        60 liters is HUGE. highway cruising that's gotta be a near 500 mile range.

        ED: and bets on how long before the first FMIC kit comes out? lol
      1. spool twice's Avatar
        spool twice -
        first M3 engine since the usdm S50/s52 that doesnt have fine detailing, looks like a bunch of ugly black plastic, where previous ones at least had nicer detailed plastics. other than that, bring on them turbos! im ready for the change, even if it doesnt have the s65 passionate howl.
      1. spool twice's Avatar
        spool twice -
        also...bring on BMS and e85 files Click here to enlarge I smell 500rwhp with just a stage 2 + e85 with stock exhaust.
      1. maxnix's Avatar
        maxnix -
        Click here to enlarge Originally Posted by andrew20195 Click here to enlarge
        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.
        The current N55 DME is 1024 bit RSA encrypted. Pretty tough to crack.

        Only Cobb and Dinan(?) cracked the previous 256 bit encryption scheme on the previous N55 DME.
      1. maxnix's Avatar
        maxnix -
        An oversquare design also allows larger size valves.

        So far no one has reported the diameters of the S55 valves.