• 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. Torgus's Avatar
        Torgus -
        It will be interesting to watch the aftermarket adopt this engine.

        Really wished they had bumped the displacement up. I wonder what turbos it has...
      1. andrew20195's Avatar
        andrew20195 -
        Click here to enlarge Originally Posted by maxnix Click here to enlarge
        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.
        So, basically tuners need to figure out the back door that the NSA convinced RSA to put in all their encryption algorithms?

        Although I see elsewhere that these ECMs can still be "bench flashed".
      1. bobS's Avatar
        bobS -
        I was reading on N54tech that rob from RB was saying these turbos should yield power/boost "in-between" the size of stock n54 and a RB upgrade. Basically this car is a little stronger than a pump FBO n54 .... stock, IMO.
      1. VargasTurboTech's Avatar
        VargasTurboTech -
        Click here to enlarge Originally Posted by bobS Click here to enlarge
        I was reading on N54tech that rob from RB was saying these turbos should yield power/boost "in-between" the size of stock n54 and a RB upgrade. Basically this car is a little stronger than a pump FBO n54 .... stock, IMO.
        Rob knows his stuff, but no real sizing has been given at least not that I have seen. A lot of speculating goes on before a car like this is released, most of it ends up falling by the wayside after not too long.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by Flinchy Click here to enlarge
        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
        15.8 gallons is freaking tiny...
      1. bobS's Avatar
        bobS -
        Click here to enlarge

        Here's a pic......
      1. Flinchy's Avatar
        Flinchy -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        15.8 gallons is freaking tiny...

        compared to a truck?

        it's got a more than large enough range for performance petrol car imo lol.

        you don't want it full to race on anyway.. unless you want to endurance or something maybe.
      1. benzy89's Avatar
        benzy89 -
        Click here to enlarge Originally Posted by spool twice Click here to enlarge
        also...bring on BMS and e85 files Click here to enlarge I smell 500rwhp with just a stage 2 + e85 with stock exhaust.
        Let's hope.... The F1x M5/M6 still doesn't have E85 support and probably won't until someone unlocks the DME to adjust the fueling tables. Honestly I won't be too surprised if the power hungry go with an Motec M1 from the get go since it supports DI fueling.

        Click here to enlarge Originally Posted by Flinchy Click here to enlarge
        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
        15.8 gallons isn't enough when you get like 4 MPG on that gas guzzling 4L V8/YSI setup Click here to enlarge

        And the real bet is how long until a quality, fair priced Intercooler upgrade comes out? Since it's Air/Water, it's def not gonna be something you can do 1/2 way. Dinan sells an Air/Water upgrade for the 550 (Nothing for the M5/M6), only $2.7k.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by Flinchy Click here to enlarge
        compared to a truck?

        it's got a more than large enough range for performance petrol car imo lol.

        you don't want it full to race on anyway.. unless you want to endurance or something maybe.
        Compared to anything. I remember the e92 and e46 tanks being way too small as well and they were bigger than this off the top of my head. Yes I know this car is more fuel efficient but still.
      1. Flinchy's Avatar
        Flinchy -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        Compared to anything. I remember the e92 and e46 tanks being way too small as well and they were bigger than this off the top of my head. Yes I know this car is more fuel efficient but still.
        16.6gal for the E9x.. wow jealous, mines only like 14gal stated (14.5 in reality)
      1. Flinchy's Avatar
        Flinchy -
        Click here to enlarge Originally Posted by benzy89 Click here to enlarge
        Let's hope.... The F1x M5/M6 still doesn't have E85 support and probably won't until someone unlocks the DME to adjust the fueling tables. Honestly I won't be too surprised if the power hungry go with an Motec M1 from the get go since it supports DI fueling.


        15.8 gallons isn't enough when you get like 4 MPG on that gas guzzling 4L V8/YSI setup Click here to enlarge

        And the real bet is how long until a quality, fair priced Intercooler upgrade comes out? Since it's Air/Water, it's def not gonna be something you can do 1/2 way. Dinan sells an Air/Water upgrade for the 550 (Nothing for the M5/M6), only $2.7k.
        LOL good point, very good point Click here to enlarge

        I'm sure some would want to just ditch the A2W and go A2A? sure, A2W has some benefits, whatever.. the A2A is simple and cheaper.. and not sitting on top of the engine

        surely there has to be enough room for a large enough one in the front bumper to overcome efficiency to make the A2A a better long term option. Once you get an A2A core larger (well, larger enough) than you can get the A2W, it'd be better. And lighter.

        This is discounting those that drag race and will fill it with ice. Not really possible to keep the tank full of ice lap after lap on the circuit Click here to enlarge

        and $2.7k OUCH... i'm sure someone could make a A2A FMIC kit for much less and still rake it in lol.
      1. benzy89's Avatar
        benzy89 -
        Click here to enlarge Originally Posted by Flinchy Click here to enlarge
        I'm sure some would want to just ditch the A2W and go A2A? sure, A2W has some benefits, whatever.. the A2A is simple and cheaper.. and not sitting on top of the engine
        I'm there with you, that A/A > A/W, especially for a car that is marketed as a street legal road course monster.

        I guess an A/A conversion is plausible, but it all depends on the routing of the pipes. Space shouldn't be an issue since you have the air/water cores on top of the engine & I'm guessing there's a heat exchanger up in front (similar to an E9x M3 supercharger setup, Air/Water mani on top, heat exchanger up in front).
      1. Flinchy's Avatar
        Flinchy -
        Click here to enlarge Originally Posted by benzy89 Click here to enlarge
        I'm there with you, that A/A > A/W, especially for a car that is marketed as a street legal road course monster.

        I guess an A/A conversion is plausible, but it all depends on the routing of the pipes. Space shouldn't be an issue since you have the air/water cores on top of the engine & I'm guessing there's a heat exchanger up in front (similar to an E9x M3 supercharger setup, Air/Water mani on top, heat exchanger up in front).
        on second thought... it probably wouldn't be super cheap

        all new charge piping both hot and cold side as well being mandatory, and likely a new BoV/recirc valve being mandatory due to positioning of the factory stuff..that's .. well cold side + BoV is $400-$500 on N54 lol.

        still should be made for those that want if it fits, and would have to be cheaper than the expensive A>W's
      1. spool twice's Avatar
        spool twice -
        can't wait to see dyno results, or even drag results with the 7-DCT. I'm willing to bet wheel HP-to-weight ratio will be similar to an F10 M5. Crossing my fingers for the first 11 second stock M3 @ 120-122mph range Click here to enlarge
      1. Sticky's Avatar
        Sticky -
        Stock 120? I mean that would be awesome but sounds too optimistic. I think 118 sounds about right. BMW usually gets the M3 close to the M5 in ET but never gives it the same trap speed.
      1. maxnix's Avatar
        maxnix -
        Click here to enlarge Originally Posted by andrew20195 Click here to enlarge
        So, basically tuners need to figure out the back door that the NSA convinced RSA to put in all their encryption algorithms?

        Although I see elsewhere that these ECMs can still be "bench flashed".
        They can, but the bench is not consumer device and getting the DME in and out is at least time consuming.
      1. vasillalov's Avatar
        vasillalov -
        I am curious to find out what they did with the oil cooling and the oil pan. I hope they put a massive oil cooler and would really really love to see a dry oil sump, but I doubt it.

        I definitely see myself in a M4 in the next 2-3 years.

        ...as for the 1024-bit RSA encryption being uncrackable... Is this some sort of a joke? We were hacking 4096-bit RSA encrypted SSL certificates with consumer grade laptops two years ago.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by vasillalov Click here to enlarge
        I hope they put a massive oil cooler and would really really love to see a dry oil sump, but I doubt it.
        I don't think it's a dry sump but the cooling seems to be serious.

        Click here to enlarge Originally Posted by vasillalov Click here to enlarge
        ...as for the 1024-bit RSA encryption being uncrackable... Is this some sort of a joke? We were hacking 4096-bit RSA encrypted SSL certificates with consumer grade laptops two years ago.
        Go for it and corner the tuning market. Dinan has a set of super computers working on cracking code 24/7...
      1. vasillalov's Avatar
        vasillalov -
        ^ I have no way of obtaining an ECU dump file. Otherwise I could help.
      1. 3000gt MR's Avatar
        3000gt MR -
        Looks like another Sparkplug option too. They look like Platnums. Hopefully they are 2 colder than stock N54/N55. I hate iridums and preffer coppers.