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    • VAC Motorsports builds a 300+ horsepower naturally aspirated S14B27 - 2.7 liter, 2.5 liter, and 2.3 liter S14 dyno overlay

      The S14 engine gained notoriety as the motor under the hood of the E30 M3 along with its victories in Motorsport which include DTM racing, endurance racing, and hill climb events. The version the E30 M3 originally was released with was a 2.3 liter S14B23 motor with an output of 192 horsepower. Now, that's almost 100 horsepower per liter from a design conceived in the mid 1980's and even today the motor fairs well against modern naturally aspirated four-cylinder designs.


      The S14 has seen various iterations from BMW M such as the S14B23 EVO 2 with 217 horsepower (with no cats) and the S14B25 EVO 3 with 238 horsepower. Compare this to the Honda F20C that came with 240 horsepower from the 2.0 liter four-cylinder and also modern technology such as variable valve timing and the S14 look even more impressive.

      People still race the S14 in various series and competitions today and VAC Motorsports gets customers all over the world asking for builds. What you see below is essentially an S14B27 which means a 2.7 liter version of the motor. It also features Schrick cams and a VIPEC ECU. This is a pump gas build so it is hardly the extreme side and still streetable.

      The dyno overlay below shows the difference in output between 2.7 liter S14 with Schrick 284/276 cams and 50/50 header, a 2.5 liter S14 with the same cams and DTM header, and a 2.3 liter S14 with the same Schrick cams and a 50/50 header.

      Peak output between the 2.5 and 2.7 liter only differ by 3 wheel horsepower. Fortunately the Mustang dynograph shows average horsepower and torque and the 2.7 liter shows an average gain of 16 wheel horsepower over the 2.5. The torque figures shows an average gain of 18 pound-feet at the wheels. Comparing the 2.7 liter to the 2.3 liter shows average horsepower gains of 37 wheel horsepower and 36 pound-feet of torque. Not bad for a naturally aspirated four-cylinder from the 1980's right?

      Keep in mind this is a Mustang dyno and VAC does not play with the numbers so on a Dynojet output would rise close to 250 wheel horsepower naturally aspirated on pump fuel. The S14 continues to show it is a hell of a motor and VAC certainly can help you get big power and torque out of it.


      This article was originally published in forum thread: 300+ horsepower naturally aspirated S14B27? started by Sticky View original post
      Comments 24 Comments
      1. Mike@VAC's Avatar
        Mike@VAC -
        Note: We calculate approx 25% loss on our stingy Mustang. Stock S65s dyno at 310-315 or so.

        Our dyno vs. a local Dynojet - same car: http://www.porscheboost.com/content....-E92-M3-S65-V8

        Keep in mind, this is a pump gas, smooth like stock engine build designed to last. In all out racing trim we make quite a bit more power Click here to enlarge

        If the weather ever breaks, I want to drag race this against my stock E46M3. I may be embarrassed by the result - haha.
      1. 135pats's Avatar
        135pats -
        More pics of the intake mani please...Looks beautiful.

        Nice numbers!
      1. Sticky's Avatar
        Sticky -
        I guessed around 250 on a Dynojet but it might even hit 260. Looks like about a 15% penalty on your Mustang versus Dynojet.
      1. Mike@VAC's Avatar
        Mike@VAC -
        Click here to enlarge

        Click here to enlarge
      1. Sticky's Avatar
        Sticky -
        Now that's a sexy picture.

        I wish you guys sent me more dynos and picture of your builds. You seriously do some ridiculously awesome engine builds.
      1. Mike@VAC's Avatar
        Mike@VAC -
        A good % of our clients want to keep stuff under wraps. Not surprising as they are racers. Thanks though!
      1. onisyndicate's Avatar
        onisyndicate -
        I had a chance to get an E30 m3 for 8500$ when I fist got back from Afghanistan in 2009. If it wasn't for the damn divorce i'd defiantly be rocking a 2.7 liter E30 m3 from vac.

        Great stuff though that kind of power band in a 2800lb car from the 80s it puts alot of newer cars to shame!
      1. Group.america's Avatar
        Group.america -
        Great build, thanks for posting VAC
      1. Imran@Evolve's Avatar
        Imran@Evolve -
        Nice work VAC. Thats a serious amount of power from that lump.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by onisyndicate Click here to enlarge
        I had a chance to get an E30 m3 for 8500$ when I fist got back from Afghanistan in 2009. If it wasn't for the damn divorce i'd defiantly be rocking a 2.7 liter E30 m3 from vac.

        Great stuff though that kind of power band in a 2800lb car from the 80s it puts alot of newer cars to shame!
        Need to get myself an E30 M3 at some point as well.
      1. andrew20195's Avatar
        andrew20195 -
        Very nice build and great numbers. 2.7 liters is quite large for an inline 4 cylinder. I'm not terribly familiar with the S14. Does it use balance shafts? If so, does this build retain them?
      1. leveraged sellout's Avatar
        leveraged sellout -
        Beautiful. Still a great design all these years later. I'm having dirty thoughts imagining that scaled up to a 3.8 liter S38 Click here to enlarge
      1. Group.america's Avatar
        Group.america -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        Need to get myself an E30 M3 at some point as well.

        Compelling with that low weight and a built engine like this mate
      1. digger's Avatar
        digger -
        if people want dynojet numbers then you really need to take it to a dynojet, otherwise its purely speculation based off a completely different vehicle tested across almost 3 months. you could spend your whole life arguing over dyno numbers drivetrain losses etc on forums..lol


        what are specs on the engine(s) i suspect the head was not ported to suit the bigger engine same with intake not changed hence no peak hp gain?
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by digger Click here to enlarge
        if people want dynojet numbers then you really need to take it to a dynojet, otherwise its purely speculation based off a completely different vehicle tested across almost 3 months. you could spend your whole life arguing over dyno numbers drivetrain losses etc on forums..lol


        what are specs on the engine(s) i suspect the head was not ported to suit the bigger engine same with intake not changed hence no peak hp gain?
        We have enough of an idea of VAC's Mustang that an educated guess can be made. The reason Dynojet's are mentioned is because they read higher and are popular so they serve as sort of a wheel horsepower standard.
      1. digger's Avatar
        digger -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        We have enough of an idea of VAC's Mustang that an educated guess can be made. The reason Dynojet's are mentioned is because they read higher and are popular so they serve as sort of a wheel horsepower standard.
        yeah, but there is an easier way to get numbers with less speculation that's all.

        i'm more interested in the specs of the engine though and what potential the s14 head has in general for making power. is headflow CFM comparable to the S50B32/S54B32 which stock are around 260 but can be massaged to over 300? it has a alot bigger bore than the older brothers and sisters so theoretically can fit bigger valves but never seen much info on the cylinder head development
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by digger Click here to enlarge
        yeah, but there is an easier way to get numbers with less speculation that's all.
        I'm happy to have any numbers period on a built motor S14.
      1. digger's Avatar
        digger -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        I'm happy to have any numbers period on a built motor S14.
        in isolation they mean nothing the good aspect is the overlay to give some meaning
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by digger Click here to enlarge
        in isolation they mean nothing the good aspect is the overlay to give some meaning
        They mean plenty considering how many stock S14 runs there are to compare to. There is plenty of useful data here so...
      1. digger's Avatar
        digger -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        They mean plenty considering how many stock S14 runs there are to compare to. There is plenty of useful data here so...
        any on the same dyno thought?