• 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. inlineS54B32's Avatar
        inlineS54B32 -
        Click here to enlarge Originally Posted by vasillalov Click here to enlarge
        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.
        Can you enlighten me on how you can crack a 4096-bit RSA key with a consumer grade laptop? I am a computer scientist, and would love to hear how this is possible, much less without parallelization (e.g. on a laptop without any hardware/fast GPUs/etc.). Unless you are talking about a FLAW in a SPECIFIC implementation, it's unrealistic to think this has been done - ever - much less on a single machine.

        I will give you my public PGP key (@4096 bit) - you give me yours, I will send you a message, and you derive my private key. Deal?
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by inlineS54B32 Click here to enlarge
        Can you enlighten me on how you can crack a 4096-bit RSA key with a consumer grade laptop? I am a computer scientist, and would love to hear how this is possible, much less without parallelization (e.g. on a laptop without any hardware/fast GPUs/etc.). Unless you are talking about a FLAW in a SPECIFIC implementation, it's unrealistic to think this has been done - ever - much less on a single machine.

        I will give you my public PGP key (@4096 bit) - you give me yours, I will send you a message, and you derive my private key. Deal?
        I think I know which side I'm learning towards here.
      1. VargasTurboTech's Avatar
        VargasTurboTech -
        Love it when someone who actually knows there $#@! calls
        someone to the carpet.
      1. Sered's Avatar
        Sered -
        Click here to enlarge Originally Posted by inlineS54B32 Click here to enlarge
        Can you enlighten me on how you can crack a 4096-bit RSA key with a consumer grade laptop? I am a computer scientist, and would love to hear how this is possible, much less without parallelization (e.g. on a laptop without any hardware/fast GPUs/etc.). Unless you are talking about a FLAW in a SPECIFIC implementation, it's unrealistic to think this has been done - ever - much less on a single machine.

        I will give you my public PGP key (@4096 bit) - you give me yours, I will send you a message, and you derive my private key. Deal?
        Completely in agreement here. I've been on a few projects dealing with crypto. 1024bit RSA CAN be broken with a MiM attack (as can nearly all). But that's not being done here. There's no $#@!ing way you're going to break a 4096bit RSA key using brute force. And trying to beat it with an algorithm is probably even harder. Discrete logarithms are a mother $#@!er.
      1. bobS's Avatar
        bobS -
        I know nothing about hacking ecu's but it seems there is a lot of talk about how hard this one will be. I can only hope it's achievable and not like the Lexus ISF....for the sake of future BMW tuning
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by bobS Click here to enlarge
        I know nothing about hacking ecu's but it seems there is a lot of talk about how hard this one will be. I can only hope it's achievable and not like the Lexus ISF....for the sake of future BMW tuning
        It will be achievable. One way or another it will happen. People are going to buy this car with the intention of tuning. The IS-F isn't nearly as popular of a car and it has nowhere near the following of the M3 and it never will.
      1. bobS's Avatar
        bobS -
        I sure hope so....

        I plan to have my e92 m3 for a longggg time but maybe one day I'll get this car and I'm sure the tuning will be well sorted out by then
      1. TheDeliverator's Avatar
        TheDeliverator -
        Any ideas why M division wouldn't have gone from 3.0 L to 3.2 or 3.3 L?

        Hope it's not fuel economy... This is an M engine damnitalltohell!

        It's not like e9x M's weren't selling in the last year of production due to fuel economy.
      1. inlineS54B32's Avatar
        inlineS54B32 -
        Click here to enlarge Originally Posted by TheDeliverator Click here to enlarge
        Any ideas why M division wouldn't have gone from 3.0 L to 3.2 or 3.3 L?

        Hope it's not fuel economy... This is an M engine damnitalltohell!

        It's not like e9x M's weren't selling in the last year of production due to fuel economy.
        My understanding is that the company as a whole are using a "common theme" (for efficiency/price) for their motors. Some engineers say that 500cc is the optimal volume of a cylinder, and BMW seems to agree: http://www.bimmerboost.com/content.p...rs-same-blocks

        I think what we are seeing is that this motor is based on the N54/55 "design" - and is no longer a bespoke/ground-up design from BMW M GmbH - if it were up to them, who knows what we would see.

        Don't get me wrong, with the weight savings, and the power/torque coupled with a DCT? This thing is going to FLY. However, take an M5 and compare it's throttle response to a e9x M3 - no comparison. That's what's missing (along with dethrottling), but that's another topic.

        Point is - that's where the 3.0 liter came in. If it were up to me, I would have taken the S54B32 and redesigned it - turbo it if they have to for efficiency, but hopefully just a NA 400 HP 3.2 liter ala VAC motor straight from the showroom. Click here to enlarge
      1. TheDeliverator's Avatar
        TheDeliverator -
        Click here to enlarge Originally Posted by inlineS54B32 Click here to enlarge
        My understanding is that the company as a whole are using a "common theme" (for efficiency/price) for their motors. Some engineers say that 500cc is the optimal volume of a cylinder, and BMW seems to agree: http://www.bimmerboost.com/content.p...rs-same-blocks
        Thanks...

        Click here to enlarge Originally Posted by inlineS54B32 Click here to enlarge
        I think what we are seeing is that this motor is based on the N54/55 "design" - and is no longer a bespoke/ground-up design from BMW M GmbH - if it were up to them, who knows what we would see.
        Yeah, I keep forgetting (blocking it out on purpose), that the S55 is not a bespoke M engine... You're right. Different topic Click here to enlarge
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by inlineS54B32 Click here to enlarge
        My understanding is that the company as a whole are using a "common theme" (for efficiency/price) for their motors. Some engineers say that 500cc is the optimal volume of a cylinder, and BMW seems to agree: http://www.bimmerboost.com/content.p...rs-same-blocks

        I think what we are seeing is that this motor is based on the N54/55 "design" - and is no longer a bespoke/ground-up design from BMW M GmbH - if it were up to them, who knows what we would see.

        Don't get me wrong, with the weight savings, and the power/torque coupled with a DCT? This thing is going to FLY. However, take an M5 and compare it's throttle response to a e9x M3 - no comparison. That's what's missing (along with dethrottling), but that's another topic.

        Point is - that's where the 3.0 liter came in. If it were up to me, I would have taken the S54B32 and redesigned it - turbo it if they have to for efficiency, but hopefully just a NA 400 HP 3.2 liter ala VAC motor straight from the showroom. Click here to enlarge
        There are certain carry overs but this is a fairly ground up design. The bore x stroke figures are reversed for this versus the N55. It also has its own block.

        They kept it at 3.0 liters for whatever reason.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by TheDeliverator Click here to enlarge
        that the S55 is not a bespoke M engine
        No... it is a bespoke M engine.
      1. inlineS54B32's Avatar
        inlineS54B32 -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        No... it is a bespoke M engine.
        Ahh, I am losing it... You are right - forgot that article. I could have swore that I read that this motor isn't made by the M division anymore, but if the block is different - that wouldn't make sense...
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by inlineS54B32 Click here to enlarge
        Ahh, I am losing it... You are right - forgot that article. I could have swore that I read that this motor isn't made by the M division anymore, but if the block is different - that wouldn't make sense...
        It's ok. This is a proper M motor not just an N55 with a different tune.
      1. ChuckD05's Avatar
        ChuckD05 -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        It's ok. This is a proper M motor not just an N55 with a different tune.
        good to see you approve this... i know you were skeptical as were many others... I am just pumped to know e90 m3 will be 25k soon lol ... than ill ditch my e92 335 for one...
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by ChuckD05 Click here to enlarge
        good to see you approve this... i know you were skeptical as were many others... I am just pumped to know e90 m3 will be 25k soon lol ... than ill ditch my e92 335 for one...
        The E9X will drop but not as hard as people think.
      1. 135idct's Avatar
        135idct -
        I think it comes with iridium spark plugs from factory
      1. digger's Avatar
        digger -
        Click here to enlarge Originally Posted by TheDeliverator Click here to enlarge
        Any ideas why M division wouldn't have gone from 3.0 L to 3.2 or 3.3 L?

        Hope it's not fuel economy... This is an M engine damnitalltohell!

        It's not like e9x M's weren't selling in the last year of production due to fuel economy.
        they used a bigger cylinder spacing to be able to use a bigger bore and shorter crank. no doubt to give themselves room to increase the size in due course. the factory wont want to be upping boost too much so cubic inches will probably increase at some point
      1. Dietcoke's Avatar
        Dietcoke -
        Click here to enlarge Originally Posted by TheDeliverator Click here to enlarge
        Any ideas why M division wouldn't have gone from 3.0 L to 3.2 or 3.3 L?
        Because power output wouldn't change, it could actually even decrease. Less displacement lets the turbos work more efficiently, increase it, and they will run out of breath as they have to push more air to reach the same equilibrium pressure as they're filling a larger volume.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by Dietcoke Click here to enlarge
        Because power output wouldn't change, it could actually even decrease. Less displacement lets the turbos work more efficiently, increase it, and they will run out of breath as they have to push more air to reach the same equilibrium pressure as they're filling a larger volume.
        Your premise is working on the assumption that the same size turbos would be used for any displacement and therefore is flawed.