• Jan 11, 2011
2011 BMW Z4 sDrive30i – Click above for high-res image gallery

According to a Twitter update from the folks at Automobile, BMW will be ditching the naturally aspirated 3.0-liter inline-six in the base Z4 roadster in favor of a turbocharged four-cylinder powerplant. Big news, yes, but it doesn't come as much of a surprise since BMW has long flirted with the idea of using turbocharged four-pot mills in its base models like the Z4 sDrive30i and even the 328i.

Details are slim (curse you, 140-character limit), but Automobile states that because this new turbo four would replace the naturally aspirated six, at least 200 horsepower should be on tap. We'd expect a slightly higher output, since the current engine cranks out 255 horsepower and 220 pound-feet of torque. We certainly won't mind a turbocharged four-banger with gobs of low-end power under the hood of the Z4, and we'd expect to see this new mill show up within the next year.



[Source: Automobile via Twitter]


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  • 48 Comments
      • 3 Years Ago
      So the engine is basically 2/3 of the N55.
      Since you are giving up the acoustics of the inline 6, this engine had better be faster and return better mileage.
      • 3 Years Ago
      The Z4 is now the nicest BMW in their line up as far as style. This would be a nice edition before whomever is designing their cars now screws it up.

      A turbo for with 220-230 hp and 260 torque at low rpms would move this car quickly. Audi has dropped its 3.2 V6 in favor of a turbo 4 that is just as quick.
        • 3 Years Ago
        "Audi has dropped its 3.2 V6 in favor of a turbo 4 that is just as quick"

        Yes, but the Audi V6 wasn't exactly a great motor. It wasn't very powerful given it's displacement. It was also a bit rough, slow to rev and got fairly poor mileage -- we had one for a few years in my wife's car.

        The 255HP N52 inline 6 is a far, far superior engine to the 255-265HP Audi V6 in every way and I can't think of any 4 cylinder turbo I'd rather have in its place.

        This discussion isn't just about replacing any NA 6 with any turbo 4, it's about tossing a truly great motor for something that's perhaps a bit more efficient, but inferior in every other way. And in a sports coupe?!?! No thanks.
      • 3 Years Ago
      I just started getting interested into cars. And already some cars look very similar to others. This reminds me of the Mercedes Benz F800 concept.
      • 3 Years Ago
      If the horsepower AND the torque curve is the same, no argument against downsizing....
        • 3 Years Ago
        @Scorch: I, along with many Porsche drivers, could debate that point. We might argue that a NA flat six gives the best exhaust note in the world, in the same way that many older guys would say that nothing beats the rumble of a large-block V-8...
        • 3 Years Ago
        Another overlooked point is the driving feel. I've driven many turbo 4s (Subaru WRX, Subaru Legacy, MazdaSpeed 6, Audi A4, Audi A3, Audi A5 and Audi TT) and none of them feel like a good naturally aspirated inline 6 to drive. None are as smooth, none have power delivery aw even and, of course, none sounds as sweet, though I know that's subjective.

        Specs never tell you the story about how a car drives. A hopped up SUV may do 0-60 in 5 seconds and pull 0.90g on a skidpad, but it still won't drive like a sports coupe that has the same paper specs. The same goes for powertrains specs.
        • 3 Years Ago
        Unless you count the engine note. I doubt you could find anyone outside of a Subaru forum that would say a turbo four has a better engine note than an inline six.
        • 3 Years Ago
        @simianspeedster
        None of those turbo'ed cars that you drove had direct injection, so they had very different torque curves. I have not had the pleasure of driving an Ecoboost, but I can imagine that it feels much less like a standard turbo, and more like a big V8.
      • 3 Years Ago
      I think this is good to hear! I wonder if this will lower the price of the Z4? Overall good move on BMW's part!
      • 3 Years Ago
      200 HP from a turbo 4? You've got to be kidding!!

      My 4 year old Solstice makes 290 HP and 340 Torque (with GM Perf. Parts) from a 2L 4cyl. If BMW can't make 300 from a 4 turbo, then why bother?
        • 3 Years Ago
        Hyundai can put out 276? hp from its 4 cyl, and this what BMW offers? 200 or more, thats a far cry from 300, and the Z still isn't cheap. The power will be set low to price in under the 6, which is a shame imo, but lets face it, the Z is a cruiser anymore, always has been really. Women will buy it or lease it, so its sales for BMW.

        Thank god for the Boxster - at least you can still buy a fun roadster from Germany.
        • 3 Years Ago
        who said they can't? it says "at LEAST 200"... i think that means its probably higher.
        • 3 Years Ago
        I agree with you 100% but that does seem to be about the norm for the 2 liter turbo engines out there right now. Besides, they probably want to leave a big enough gap to make people want to upgrade to the bigger engine.
        • 3 Years Ago
        I'm fairly confident it will be in the same area as the inline 6 now. How can they LOWER the HP? They wouldn't.

        They may try to just leave room for BMW performance parts. So i'm thinking:

        250hp / 250 torque. With a Dinan Chip it would easily produce 300/300 just like the tt6.

        i'm hoping it can somehow loose about 75-100lbs but I know that's wishful thinking.
      • 3 Years Ago
      Exactly -- see my post below.

      Maybe those of us who care about inline 6s are a dying breed, but I'll take a naturally aspirated inline 6 over a V6, V8 or turbo anything. I6s are naturally balanced in a way that few engines (aside from a V12, of course) can match.
        • 3 Years Ago
        Agreed. My point was that naturally balanced engines are almost always smoother than the the more common imbalanced engines that need engineering assistance like counter-rotating balance shafts, etc. That's why I compared the inline 6 favorably to any V6, V8 or turbo 4 -- they're by far the most common options these days. Sadly, inline 6s are becoming almost as rare as flat 6s...

        I've never driven a Subaru flat 6, but I've ridden in one crazy 911 turbo from the late 1970s (tuned like crazy) and briefly driven a mid 2000s Carerra S. Both were a bit rougher than a stock inline 6, but that was probably a function of their high tune and stiff engine mounts.
        • 3 Years Ago
        My daily driver was a Subaru SVX with a flat six. It had suspension subframes and a stiff chassis, very sophisticated NVH management. *Great* highway cruiser.
      • 3 Years Ago
      Awesome... More turbos in anything is a plus for the world in its entirety
        • 3 Years Ago
        A straight-6 isn't too difficult to produce - and easier than a V-6, because you don't need to go through various contortions to balance an inherently unbalanced engine. It's why the straight-6 engine predates the V-6 by several decades and is used in very large (e.g. industrial / naval / generator) applications.

        The only real advantage of the V-6 is that it is a very compact only 3 cylinders long. That allows for easier transverse packaging over a pretty much anything else one might use.

        For BMW, they design the car with a north-south longitudinal FR drivetrain, and space for a straight 6, so it's not an issue for them.
        • 3 Years Ago
        It's not. At least not if you like N/A I6 (particularly in a bimmer) and V8 engines these seem to be the first endangered by all the turbo hype.
        • 3 Years Ago
        The weight of the shorter block is offset partly by the turbo.

        The real advantage here is in packaging a shorter, more compact 4-cylinder engine, rather than a longer 6-cylinder engine.
        • 3 Years Ago
        Don't forget the lower weight that comes with it!
      • 3 Years Ago
      Since the 3-series started out with four bangers as their base engines I see no problems on that end. Nor do I have complaints about power. A turbo four or V6 will provide plenty of power.

      I just have two problems, more like worries. The first is that this heralds the death of the V8. The second is that the quest for tighter packaging creates stubby cars with little of the long nose/short deck/cokebottle shape that I so love in an automobile. I realize that this is a personal preference, but I'd miss V8s and classical looking cars even if they were replaced by something more efficient.
      • 3 Years Ago
      Well, I hope you're right and I wouldn;t object to adding a lower cost Z4 option, but that's definitely not what the article says. It says BMW is planning to replace the N52 with a turbo 4, and that's a whole different discussion than adding a turbo 4 option.
      • 3 Years Ago
      Would it come with any drop in price?
        • 3 Years Ago
        i doubt it would. I also doubt a new 4cylinder turbo would have any less power than the outgoing i-6. it wouldn't make sense to offer less power unless the weight of the car was dramatically changed, and we all know weight loss in anything nowadays is almost the way of the dinosaurs.

      • 3 Years Ago
      This makes sense. BMW should have brought back the 4-banger a while ago.
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