What is this witchcraft? What is the purpose of that mod? What was wrong with OEM? Am I correct in understanding that vacuum doesn't CONTROL our throttle, but is a byproduct of twisting the throttle as the butterfly valves open, sucking in more air, venturi effect, etc.???
I bought one of these a few years ago and it's still in a drawer, because I couldn't find a good way to mount it (also physically bigger than I expected). I never thought about doing it this way... sometimes simple is best!