Sequential multi port injection9/1/2023 ![]() ![]() Trey was right, these motors are very, very impressive. It is no wonder a good friend of mine, Trey Thurman from PCM, told me a year ago that PCM had something special coming for 2016 and that I would love it. The best part though was that these new engines are up to 27% more fuel efficient than last year’s comparable engines. The New PCM Direct Injection H5 and H6 are 33% faster 0 to 23 mph than last year’s PCM ZR409 & ZR450. Needless to say that after our personal experience, we weren’t terribly surprised when we received the engine comparison specs from PCM. We tested them side by side, and the difference was negligible. We were really surprised because that is the max amount of weight that we could get to wakeboard speed with my 2015 supercharged 550 hp PCM XR7. total weight) up to wakeboard speed at Deer Creek. We were able to get a fully ballasted Ri237 (10,500 lbs. But the really big surprise happened when we tested the new PCM H6 engine here at altitude in Utah. I can tell you from personal experience that the new H5 just plain stomps the last year’s PCM ZR409 out of the hole on a Centurion FS33 with max ballast. Well, enough of all that tech stuff – So what does direct injection mean for you? It means you can have an engine that has more torque (low end power) than a sequential fuel injection system has, and you get that extra power while burning less fuel. This so-called ultra-lean burn mode sacrifices a bit of outright power but greatly reduces the amount of fuel used during times when the (boat) requires very little grunt (idling, decelerating, etc.). For example, some GDI engines can adjust the timing so that a lesser amount of fuel is injected during the compression stroke, creating a much smaller, controlled explosion in the cylinder. MPFI systems can only add fuel during the intake stroke of the piston, when the intake valve is open. ![]() By moving the injector into the combustion chamber, GDI (gasoline direct injection) gains a few advantages over the previously discussed systems.īy putting the injector inside the cylinder, the engine’s computer gains even more precision control over the amount of fuel injected during the intake stroke, further optimizing the air/fuel mixture to create a clean burning explosion with very little wasted fuel and increased power delivery.Ī GDI system also has more flexibility regarding when in the combustion cycle the fuel is added. Direct injection takes this evolution to the next level by placing the injector inside the combustion chamber. What are the advantages DI of over the old SFI system? Antuan Goodwin (engine writer for Cnet) said that readers may have noticed that during the jumps from carburetion to SPFI (single port) to MPFI (multi-port), the point at which fuel is added to the intake charge, has moved from before the throttle to the intake manifold and onward to the individual intake runners - closer and closer to the combustion chamber. Sequential fuel injection has been used in marine engines for several years and is the system that is currently used in most new towboats and the system PCM used on engines until 2016.ĭI (Direct Injection) is the next evolution of fuel injection where the fuel is injected after the intake valve directly into each cylinder at over 3000 psi. This system was way more fuel efficient and created way more power than the carburation systems it replaced. This air/fuel mixture is pulled into the cylinder past the intake valve on the intake stroke of the piston and is then compressed and ignited. Each of these injectors puts fuel into the system at 30-40 PSI before the intake valve. Here is some basic information about injection systems.īasically, a SFI (sequential fuel injection) system has a fuel injector for each cylinder. Sequential Fuel InjectionĮver since PCM came out with the new direct injection H5 and H6 engines, we have been asked what the difference is between direct and sequential injection and if PCM is the only company using direct injection. ![]()
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