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Message: [QUOTE="CurtisF, post: 1062118, member: 829"] We're on the same page with injection window. And yes on a PMR motor you aren't using all that much fuel, especially on a bigger injector (i.e. 250cc's, 300cc's, 400cc's, etc). But forget what the injector CC's are claimed to be, and I'm not even starting a pissing contest with vendors about who can more accurately pinpoint their specs. None of that matters unless you are really and truly trying to squeeze out every drop of fuel that they are capable of trying to win a drag race or sled pull. This thread isn't about that. It's about making as much useable power as you can without windowing the block. That won't happen until you focus specifically on what I've already said: amount of fuel injected at a specific time and specific duration. The amount of fuel available and amount of fuel injected are two completely different things. The point when the amount of fuel available becomes a problem is when you don't have enough available to begin with, and you try to get the tuning to squeeze out every last drop to reach your power goal. So if you want 450hp on a PMR motor and you want to achieve it with a 160cc injector, you'd better rethink your build here, because you aren't reaching that 450hp mark. If you come close to 400hp on a 160cc injector, you aren't doing it efficiently enough to make that power useable in the first place. So you go with an injector that is capable of more in order make that power possible, and to make it useable. Time and time again on this forum people say they want "X" horsepower, and time and time again the response is to suggest an injector that will juuuuuuuuuuust baaaaaarely get you there. Ok fine, but can you actually use that peak HP reliably? The answer is no. The other part of the equation is the nozzle size. Again, don't pick nozzles that will juuuuuuuuuuust baaaaaarely get you there. Pick nozzles that will make it easy to reach the power goal. That way you or your tuner have more flexibility in that injection window. But it has to be a careful decision, because like I mentioned already, larger nozzles can be more of a bear to get dialed in. But if you have teeny weenie nozzles to begin with, you've already choked yourself down to a lower useable power limit, and immediately limited what can be accomplished. A longer duration as that injection window shrinks will always equal higher EGT's and more smoke. There's no way around it, and suddenly you reach the tipping point where you no longer have useable and reliable power. That's when you see people reach for band-aids. For example, when I see someone running 160cc injectors and water injection, I immediately see they chose the wrong injector and nozzle size in the first place. In short, get an injector that can easily reach your goal, and one that you can live with as a daily driver. The rest is entirely up to the tuning to achieve it..... and keep the motor alive and happy. [/QUOTE]