A picture of a fuel injector (above), a few facts and a lot of supposition is all we know about the fifth-generation small-block engine on its way from General Motors. It is expected to debut sometime shortly in the C7 Chevrolet Corvette and be rolled out with the next-generation full-size pickup trucks, but no one is exactly sure what it will be.

What we do know is that it will have a cast aluminum block, direct injection, variable valve timing, a higher compression ratio and 4.4-inch bore centers, flex-fuel capability and it will be more fuel efficient. From there, the site EngineLabs.com runs through the rest of the rumors and the odds of them becoming reality. In the "Sure Bet" column, EL figures a more aggressive system of Active Fuel Management will be introduced for even greater efficiencies.

A surprising prediction to which EL gives a 98-percent chance regards displacement: several outlets have talked of a "base" 5.5-liter model with 440 horsepower that mimicked the numbers of the 2010 Corvette Racing C6.R, but EL expects a 6.2-liter and 5.3-liter V8 and a 4.3-liter small block that it thinks could be a V6. Engineers have already said that the 5.5-liter (or 5.3-liter if EL is correct) will not go into the Corvette. The site also thinks the C7 will be introduced with at least 450 hp. Lower down in the 90th percentile odds are innovations like a raised camshaft tunnel, dry-sump oiling for performance variants and eAssist.

After that, things get rather cloudy. A concentric camshaft only gets even odds, there's just a 20-percent chance of three valves per cylinder, and a mere 10-percent chance of an active intake manifold. As for that "advanced combustion system" that we know is coming, EL wonders if it will be genuinely all new, or a new variation on the Otto cycle. Head on over to Engine Labs to get all the insight and their rationales.


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  • 63 Comments
      carguy1701
      • 2 Years Ago
      >4.3-liter small block that it thinks could be a V6 lol no. They already have a V6 engine family for the base truck engine: the High Feature V6. I remember hearing/reading something on I think GMInsideNews about how they'd looked into that already, and that simulations showed it wasn't worth the effort to build.
      Ron
      • 2 Years Ago
      I am pretty excited about the Gen V's.... N/A direct injected motors easily hit 100+ hp per liter, so if they in fact retain the 6.2L it should easily push 500-600 hp. in any case, a direct inject flex fuel engine will make the tuners happy....
      MONTEGOD7SS
      • 2 Years Ago
      Direct injection is far from perfect at the moment. Hopefully this will be a dual injector setup so the backs of the intake valves can be flushed to remove carbon. BMW and VW have horrible carbon buildup, and on my MS3 it's something I'll have to keep an eye on. There are dual injection systems out there like Lexus, or Nissan with a small injector in each port for two injectors per cylinder.
        Nathan Loiselle
        • 2 Years Ago
        @MONTEGOD7SS
        What you describe as a small injector in each port is multi-port injection. It's not direct injection. Direct injection has an injector that pumps fuel directly into the cylinder after the valve structure. Like a diesel engine would. However BMW's do inject the fuel into the incoming intake stream which can cause fuel to be blown back onto the top of the valves.
          MONTEGOD7SS
          • 2 Years Ago
          @Nathan Loiselle
          Apparently your reading comprehension is lacking. I am well away that having an injector in a port is multi port injection, and the Lexus version that I referenced has those, as well as direct injectors. BMWs do not inject fuel into the intake on their direct injection systems, that's why they are called direct injection. They have the same problem as everyone else, the EGR sends fuel into an intake tract that has no liquid fuel to clean the back of the injectors. It has nothing to do with reversion.
        Julius
        • 2 Years Ago
        @MONTEGOD7SS
        But GM has been using direct injection for years... and I'd think they would know how to work out the kinks by now (including adjusting EGR and intake valve timing to avoid buildup)
      protovici
      • 2 Years Ago
      Welcome to the 21st centruy GM. Lets go talk to Chrysler about producing more efficient V8's. I dont want to see a 20 speed transmission in a truck with 19th Century thinking (figure of speech here). Push rods are a thing of the past, but fun!
        Serge
        • 2 Years Ago
        @protovici
        That shows how much you know about engines and the possible applications of the different technologies. Nothing wrong with push-rod engines, I would say they're better than DOHC in a lot of cases. A GM LS engine is smaller and much lighter than most DOHC V8 that make similar power and are around the same class, no flat-plane crank Ferrari or sleeveless M3 engines. You argue about efficiency, take these real world examples into account (taken from fueleconomy.gov): 2012 Camaro - 6.2L V8 425hp 6speed - 15/24mpg 2012 M56 - 5.6L V8 420hp 7speed - 16/24mpg 2011 E550 - 5.5L V8 382hp 7speed - 15/23mpg 2012 IS-F - 5.0L V8 416hp 8speed - 16/23mpg 2011 M3 - 4.0L V8 414hp 7speed - 14/20mpg (completely different engine, normally wouldn't compare... but it still proves my point) Not bad for an ancient engine using less gears in a less aerodynamic car...
        Sir Duke
        • 2 Years Ago
        @protovici
        Push-rods are not a thing of the past. " A thing of the past", is something that is extinct. Like the 5.0 Liter V10 that BMW once produced, oh so long ago. Push rods are still evolving, making excellent horsepower and kicking much ass.
          Sir Duke
          • 2 Years Ago
          @Sir Duke
          You act as if GM has never had a DOHC V8. The NorthStar, C4 ZR1, Aurora V8. Packaging wise, it's limited as to how/where you can deploy it. Anyone who tries at this point to get into the push-rod game today, would be a a severe disadvantage. GM & Chrysler enjoy such a huge lead in that technology.
        RodRAEG
        • 2 Years Ago
        @protovici
        Both pushrods and dual-overhead cams are ancient considering both originated in the early 20th century. Either you're just ignorant and don't know your history, or you're a hypocrite for criticizing a company for innovating one ancient valvetrain design over another.
          Rick Cavaretti
          • 2 Years Ago
          @RodRAEG
          Yes, a few OHC designs predate other tech, but that certainly doesnt make it more primitive than a push rod design. But consider this. H.G. Wells described lasers in his books in the late 19th century, but we didn't get the technology to make them work until 60 years later. OHC designs were simply ahead of their time.
          mark and connie
          • 2 Years Ago
          @RodRAEG
          Sir duke, You are absolutly correct, But did you know John Delorean had a Pontiac 428 ohc ready for market around 1965? Then GM said Pontiac couldn't because they were afraid that motor may end up in a GTO or the car Delorean wanted to produce the Banshee 2 seater. But GM wanted no internal competition for Corvette. GM was scared to death of Pontiac.... PMD should still be alive today instead of Buick.. Itiot GM
          protovici
          • 2 Years Ago
          @RodRAEG
          Both are correct and incorrect. Both designs are old technology, hell, internal combustion engines are a thing of the past, but have yet to decide to move from them. Im speaking in terms of quantitative science. You peoples must be having a bad day or cant understand forward thinking. lol
      Beardinals
      • 2 Years Ago
      I see them hitting 30mpg Hwy in a Vette.
        QCRamAir
        • 2 Years Ago
        @Beardinals
        Corvettes have been capable of 30+ mpg on the highway since '97 with the LS1 coupled with the double overdrive 6-speed. They may not have been rated 30 HWY by the EPA, but many owners have seen 30+ on the highway on a regular basis.
        AXEL
        • 2 Years Ago
        @Beardinals
        Highway miles is all down to the final drive of the transmission. GM has usually had a lower final drive to make it seem like a more economically sound manufacturer, whether its engines were actually greener is another argument. But the MPG's are attainable so I guess its a legit practice.
          Julius
          • 2 Years Ago
          @AXEL
          Well, the fact that the Corvette makes better.mileage than a comparably-powered 911 (read turbo)...
          Justin
          • 2 Years Ago
          @AXEL
          It also depends on the engine. He didn't say that was the only variable.
        The Wasp
        • 2 Years Ago
        @Beardinals
        It's also a 2400-pound car, so 30mpg in a Vette [which isn't really that impressive] would mean nothing for the rest of their lineup.
          QCRamAir
          • 2 Years Ago
          @The Wasp
          Considering the C6's weight ranged from 3150 - 3350, depending on trim, I'd be quite surprised to see the C7 weigh anything under 3000 lbs. Don't get me wrong: It'd be terrific to see an already incredibly-light car (for what it is) get even lighter, but I wouldn't hold my breath on a drastic diet.
          Justin
          • 2 Years Ago
          @The Wasp
          It still means a lot improvement-wise, if they can up the mpg in the Corvette while getting more performance. Other vehicles with the engine will likely see similar improvements over Gen IV.
          The Wasp
          • 2 Years Ago
          @The Wasp
          Well...it seems I was a bit hasty in stating the Corvette's weight -- it's quite a bit heavier than 2400 pounds. In any case, it's much lighter and more aerodynamic than GM's other vehicles, so fuel efficiency is not comparable to the higher volume models.
        Thipps
        • 2 Years Ago
        @Beardinals
        with our 2002 six speed we get 35mpg at 70mph....its our economy car for long trips
      RodRAEG
      • 2 Years Ago
      Kudos to GM for bringing direct injection and variable valve timing to their small block V8s. Cue the morons who will chime in that pushrods are an old design without realizing their own hypocrisy.
        The Wasp
        • 2 Years Ago
        @RodRAEG
        Does saying that pushrods are old technology make them new technology?
        samagon0
        • 2 Years Ago
        @RodRAEG
        OHV, OHC (D or S) is all 'old' technology. OHV has seen less innovation in the past 20 years or so compared with OHC, which is why it's considered 'old' tech.
      john m
      • 2 Years Ago
      Electromagnetic valves are the future my friends. When they finally perfect them. Pushrods are a very old technology and I'm a quad cam guy myself BUT it is amazing what GM can do with this engine. And there is no doubt that pushrod V8's are smaller, lighter and don't forget cheaper than their quad cam competitors while producing close to the same power.
        BipDBo
        • 2 Years Ago
        @john m
        The last I heard, electromagnetc valves were the theoretical holy grail of engine improvements, but have yet to be anywhere close to feasible. Have there been recent advancements that indicate this might actually one day happen on the mass market?
          Dark Gnat
          • 2 Years Ago
          @BipDBo
          I thought I remember reading something about BMW messing with electromagnetic valves. The hard part is getting them to reliable function in correct timing as the revs change. Plus the solenoids are more complex and fairly bulky.
        carguy1701
        • 2 Years Ago
        @john m
        We're still a few years away from camless engines, and we'll likely see them in diesel form first (the lower engine speeds of a diesel mean less electrical complexity is required).
        Carbon Fibre
        • 2 Years Ago
        @john m
        Wow, not heard of such thing. I will look into it. Eng student.
      lrx301
      • 2 Years Ago
      Just because the push rod engines are still being produced doesn't mean they are modern technology. small block (push rod) engine was an excelent design back in the 1950's. It's simple and cheap to make, perfect for the company whose only specialty is cost-cutting. By blindly saying that the push-rod engine makes same amount of power as OHV engines is ridiculous. Those people should learn the basics of physics. The push-rod engine can't rev really high because its valvetrain is too long, the inertial force is too large for the long valvetrain to handle. Secondly, the modern engine technology is all about control, you have to give the control algorithm something to play with. The pushrod engine does not have the capability to control the phase between intake and exhaust. Its cam phase control is to shift ALL valve openning together. That doesn't mean the OHV engine is hard to make. any OEM can make OHV engines nowadays. However, it only depends on the OEM's priority, if the OEM doesn't want to commit newer technology, doesn't want to handle the product complexities, or just want to make do with mature technology, they are still making the push-rod engines. BTW, the pushrod engine is perfect for pick-up trucks, which doesn't need much power but a lot of torque.
        Julius
        • 2 Years Ago
        @lrx301
        Umm... huh? Here's another screed proclaiming "OHV" engines are superior to "pushrod" engines. Minor points you forgot about: 1) pushrod engines nowadays are ALL OHV. They are not OHC. 2) yes, OHV engines cannot rev as high as OHC ones, but as in anything, the design has to match the application -something you already hint at with trucks. And the typical American buyer doesn't rev their engines anywhere near redline during normal driving, so the benefit of OHC engines are often wasted. Case-in-point is the S2000... later models increased their displacement and lowered the redline to better fit US driving habits. And even with that small-displacement engine, fuel economy was not any better than say a Corvette 3) OHC engines are already physically compact, as evidenced by the many Miata and Rx7 conversions that use GM LS-series engines. 4) Vipers have trialled concentric-lobed cams, which do have the potential to allow independent intake/exhaust variation. Point being, if being able to get power from high revs and small displacement engines constitute your criteria for "modern", then you should be more of an advocate for rotaries instead.
          lrx301
          • 2 Years Ago
          @Julius
          ok,the OHV was a typo, it should be OHC.
        Dark Gnat
        • 2 Years Ago
        @lrx301
        OHC is actually older technology than OHV. OHV gives you a smaller engine in terms of external dimensions that allows it to fit under the sloping hood of a small sports car, such as the Corvette.
        Nathan Loiselle
        • 2 Years Ago
        @lrx301
        I have trouble believing someone who mistakes "push-rod" and "OHV" as being distinctly different as someone who is knowledgable. If you're willing to completely redesign the headers then you can easily introduce electro-hydraulic timing like Fiat's multi-air system. This allows for complete individual timing control of each and every valve. OHV engines also permit cylinder deactivation which OHC engines have a greater issue with. OHV engines tend towards a lower centre of gravity and don't contain particularly greater, or lower, parasitic losses as a result of the cam design. The engines are capable of speeds that OHC engines are capable of in production vehicles and frankly a slower moving crankshaft does tend towards a quieter engine. Companies like Chrysler and GM have proven that "push-rod" engines are capable of the same performance, emissions, control levels, and fuel economy as OHC engines.
        findyourniche
        • 2 Years Ago
        @lrx301
        Too make power you gotta burn fuel. To burn fuel you have to move air. You can use a small pump, and run it at high speed, or use a larger pump and run it slower. You wanna compare two engines, compare the torque curve, that is the true measure of engine output. A large displacement engine does not need to rev high to make power.... it does'nt mean that it can't. Z06 engines run up to around 7k.....nascar engines rev over 10k OHV does not mean pushrod, because even a OHC, SOHC, DOHC has overhead valves. And overhead cam in an older design than pushrod....you sir are a flat earther. There are plenty other mainstream/bandwagon engines out there. Go buy one....and in ten years when your euro-trash sport sedan craps out, and an engine replacement bill is $15k, i'll buy it for pennies on the dollar, swap in a GM truck V8 with some head work and a cam, and it will be faster than you would have ever made it.
        Carma Racing
        • 2 Years Ago
        @lrx301
        Three nice things on a sports car with a pushrod engine are lighter weight for a given displacement, lower center of gravity and smaller package. DOHC is the best way to get the most power from a given displacement, but there is no displacement limit on road cars.
      pwr2lbs
      • 2 Years Ago
      Direct injection sucks! Ask any Tech out there that is cleaning off intake valves after 20k miles. Its a service interval now.
        Nathan Loiselle
        • 2 Years Ago
        @pwr2lbs
        Hold on. Why would the intake valves need cleaning in a direct injection engine? You do realize that the fuel is added after the valves, right? Anyways, it's not better or worse than manifold injection. It's just different. It's better when accelerating as it allows for a high compression ratio with more power but it pumps out worse emissions when cruising.
          Brian P
          • 2 Years Ago
          @Nathan Loiselle
          The problem is not the fuel building up, the problem is carbon particles from the exhaust and oil mist from the crankcase ventilation system. Almost all gasoline engines have "overlap" - the intake valve starts opening a little before the end of the exhaust stroke and the exhaust valve closes a little into the intake stroke. Under some operating conditions, this can cause a bit of exhaust to backflow into the intake ... and any carbon particles present can collect on the back of the intake valve. With normal port injection, the gasoline washes these particles off. With direct injection, that doesn't happen. Not all direct injection engines have been having trouble. Careful timing of valve events and intake/exhaust tuning can manage this, and also, careful positioning of the injector and injection timing can direct some of the spray past the back of the (opened) intake valve. The other approach is to use both direct and port injection, and use port injection under some conditions when it is either an efficiency benefit to do so, or simply to ensure that the back of the intake valves get washed once in a while.
          Krazeecain
          • 2 Years Ago
          @Nathan Loiselle
          @Brian Having 2 fuel injection systems on one engine seems like overkill for a seemingly simple problem. Isn't there some kind of cleaner you could periodically spray into the intake while the engine is running? Like seafoam?
        cfphelps
        • 2 Years Ago
        @pwr2lbs
        GM's 4 and 6 cylinder engines with direct injection do not exhibit these problems like other makes, so there is no reason to fret over the Gen V having issues, either.
      Mercer
      • 2 Years Ago
      I hope they won't ditch the pushrod design (which I believe they will).
      graphikzking
      • 2 Years Ago
      443hp and then a performance exhaust package for cheap ($500-1200 range) and get me like 455hp. GM could make a lot more profit per car if they did the following: 1. Offered more intake systems as options (even 6 months after purchasing) - 5hp and better intake sound. 2. Exhaust + HF cat = +8-12hp 3. Headers = +3-5hp. +20hp total so like 463hp for a base engine with a few add-ons would be a nice deal. These are just estimates but it would make dealers and Chevy more money if they were reasonable with these add-ons. I really hope they bring the aluminum/carbon fiber to the car in more parts to lose some weight. If they can drop about 30-50lbs and bring in a better interior, crash standards, emissions I'd call it a real win! Customization can make them a lot of money - just like it does at Mini.
        Nathan Loiselle
        • 2 Years Ago
        @graphikzking
        After market, dealer installed parts would be nice. And it would be a nice way to remind people of a more prosperous time for the company.
        Julius
        • 2 Years Ago
        @graphikzking
        Big issue here is if the high-flow cat would remain 50-state legal. And don't forget, certain jurisdictions have exhaust sound limits, too.
      Tam
      • 2 Years Ago
      hopefully this is the ats-v engine
        JJ
        • 2 Years Ago
        @Tam
        in the ats they will use a twin turbo v6
          Tam
          • 2 Years Ago
          @JJ
          i guess a guy can hope until it gets confirmed
          Sir Duke
          • 2 Years Ago
          @JJ
          says who?
          icon149
          • 2 Years Ago
          @JJ
          @Sir Duke, I don't know who says, but i hope JJ is right, and i hope they use the same engine in a Camaro Z28, along with a diet and serious track chops.
          carguy1701
          • 2 Years Ago
          @JJ
          That hasn't been confirmed.
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