Originally Posted by ringer4x4
how much of a gain is expected on a 4.o with just a free flow air filter? wish there was one that just controlled the engine....most of the them change shift points, i have a manual trans so paying for a major feature/ selling point that i cannot use, which is why i am looking for a more cost effective alternative
It's actually a fallacy that manual transmission owners have no use for a tuner. Tunes are written quite predominately to improve the air-fuel ratio across the ENTIRE RPM range to a point of optimal consistency. THAT is the major feature / "selling point." ATX vehicles simply benefit from changed shift points and shift hardness.
I should add that I have learned these things while hosting/joining Doug from BamaChips at multiple dyno days as I watched him alter tunes after each pull to meet optimal A/F levels, as well as several other engine performance aspects.