Can I join your club?The only filter that matters is the oil filter. Starting a new anti air filter group. So far one member. My evidence is my air filter doesn't even look dirty after 50k so how much dirt is really going in per mile, and my platform is most of that is blown out by the exhaust stroke.
Those air filters in the engine bay behind the radiator, what is the science behind improving power with hot air intake versus cold?
Hot air intakes....a common discussion topic on many enthusiast forums. On my platform, the MK7 VW Golf and all it's variations (GTI, R, Sportwagen, Alltrack, blah blah blah), there is a gentleman that has tested the $hit out of intakes, OE intake mods, and intercoolers w/r to flow and air temp. Great data set. With a modified turbo engine, you have other things going on beyond intake air temp to the turbo, you have flow as well and you have to keep both in mind...it's a balance. Yes, colder air is always better than hotter air but keep in mind the turbo heats this air A LOT and then you have an intercooler to deal with that to bring the temps to the throttle body back down. A larger flowing open-intake vs. stock will pull in warmer air especially around town (on the highway, it's not much different due to flow through the engine bay of outside air through the grille). However, it also flows much more air (keep in mind these are modified/tuned so 2x+ the amount of stock boost). When you run a larger aftermarket intercooler, you can deal with this relatively small amount of extra heat introduced from the engine bay. And you are also forgetting all that glorious turbo noise you get with an open intake!