ok so i was reading on the o2 sim for adding headers and cameacross this thread. http://forums.maxima.org/5th-generat...wn-o2-sim.html

carrrnuttt pasted a site (below) that states using non foulers to up your mpg while adding performance by leaning out your fuel mixture. now i can build an engine and all but ecu's, o2, and electrical work is more greek to me. so i was wondering.. with stock ex manifolds would this increase mpg and add a bit of power to the engine. discuss..

http://www.energeticforum.com/renewa...n-foulers.html

edit: ok im gonna brainstorm this and this is what i came up wit hbut not sure if it makes sense.
With the o2 spacedout it will read less oxygen, thus fooling the ecu to thinking it is not getting as much oxygen as it really is, this in turn would make the ecu dump less fuel in which in turn would advance timing as well inducing a better mpg and more hp and tq... am i correct on this or am i way off..?

running lean would make the engine runs very hot and possibly melt the valves.
even so your MAF would get the air volume value for the ECU to derermine how much gas it needs.

ah MAF, i didnt think of him. so the fouler is basically junk then. i knew it was to good to be true or it would be all over the forum

its meant for the downstream O2 which does not really regulate the A/F ratio, just monitors catalytic efficiency

That would probably make the engine run leaner but that is not always good. During closed loop, the ecu is keeping the AFR at the optimum level.

Also, those anti foulers will not affect the WOT performance because the ecu uses the MAF for open loop readings.