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Originally Posted by ZX-12R  I'm curious why this wouldn't be a sport riding issue. In the example, the amount of fuel required to get a certain torque output was reduced but the engine is still capable of buring that larger amount of fuel. This is where you get into jetting and fuel remapping to take advantage of the efficiency gains of the new exhaust system. By increasing the amount of fuel at that given throttle input you can increase the power of the engine over stock (a sportrider's or HP nut's goal). This also means you can have power gains all throughout the RPM and throttle range as opposed to WOT only. |
There's a couple of things going on here. I am trying to consider the pipe alone only. I know it's multi factorial but for the purposes of this discussion assume that the hypothetical bike in question is properly fuel mapped with and without a pipe. If we start adding other things we might as well add cams and raise compression too.
It's true, at say 25% throttle rotation you can have a gain, but how could that matter if you could have that same gain at 27% throttle rotation without the pipe?
If you accept that it's pulse timing (do you?) that makes power in an after market exhaust and not a reduction in back pressure then you have to ask if logically part throttle will effect pulse timing.
If it does effect pulse timing, and I don't see how it couldn't if air intake is radically changed because the butterfly is closed, pressure in the cylinder is reduced etc.
I totally agree that after market exhausts can increase performance under some conditions, those conditions are the ones the exhaust was designed to exploit, namely high gas escape velocity from the cylinder e.g. WOT.
I just think that by definition people don't ride at WOT if they are rolling on the throttle. Where is it being rolled on from? Part throttle.