 Dual-wielding, dual-exhaust, dual-turbos. I do remember some of the basics of CQC. And of course, dual injection. No matter what you do with your car, it needs the right amount of fuel at the right time to get the job done. But sometimes one set of injectors isn't enough. Luckily, there's a solution for that. It seems each car community has a different name for that solution, whether it's secondary injection, auxiliary injection, dual injection, or MPI. But ultimately, the motivation is the same. It's about having the ability to greater supply and more dynamically control fuel injection in order to overcome the limitations of a single set of injectors by installing an additional set. Those limitations come in various forms as well. So the design and application of each dual injection system is just as varied. On one extreme, you've got massive power builds like this GTR. The VR38 is port injected, meaning it's easy to simply replace the stock injectors with much larger aftermarket injectors in the stock location to greatly increase fuel supply and make a lot more power. But even injectors that are over double the original flow rate still can't always reach the potential of many built GTR engines. So the only option is to install a custom intake manifold that supports an additional fuel rate, allowing you to add an entire second set of big old port injectors to dump and bucket loads of fuel into the thirsty engine. Another benefit of this kind of setup is the ability to control each set independently. The bigger port injectors get, the more you potentially sacrifice things like easy startup, smooth idle, and steady cruising. With this type of setup, you can implement more reasonably sized injectors as your primary set for street driving and then go as big as you need on your secondary set for achieving your max power loss. It's a bit complicated, but it's a highly modular option for advanced builds. But not everybody needs this kind of craziness. In fact, on the other end of the spectrum, some cars actually come right from the factory with dual injection like on this second generation Raptor. But the main difference is that instead of controlling a dozen port injectors, it has one set of direct injectors and a second set of port injectors. The processes and designs of an OEM direct plus port injection system are a topic that I could talk about for hours. But the Cliftonauts version is that with modern engine management, the ability to use both at the same time allows for the benefit of both while overcoming many of the weaknesses of each. This truck can use each set of injectors in varying percentages depending on the operating conditions of the engine. For example, fuel is delivered exclusively by the port injectors at idle, but at cruising nearly all of the fueling is delivered by the direct injectors. At wide open throttle, we can tune the proportional split to make efficient use of both systems. Ford could have just used a larger single set of either type of injector and made the same power, but that would introduce the same limitations that dual injection avoids. So don't be surprised to see more and more OEM systems just like this one in the future. And lastly, if you have cars like this Mark 7. For Volkswagen, this engine has a single set of direct injectors. They're more than big enough to handle stock power and have enough headroom to tune up quite a bit. But eventually they do run out of flow. Larger aftermarket direct injectors are super expensive, offer minimal improvement. And for a lot of platforms, they don't even exist. Plus, they still have the same problems you find on all direct injected engines like a limited injection window and carbon buildup on the valves. So for those looking to make big power with a significantly larger turbo or an alternate fuel type, the best option is to add a second fuel rail and a set of port injectors to supplement the stock direct injectors at high load. Naturally, once installed, they don't just work automatically, you have to tune for your bonus injectors. Luckily custom tuning on an access port allows a pro tuner to make use of that extra go fast juice to make as much power as the engine or you can handle.