i have seen this (A'PEXi S-AFC) on a couple guys' lancers on the forums and i dont know what it is, In fact "DJPhatroc" has one on his. unfortunatly i dont have a picture either. But its a rectangular shaped readout....maybe it's a stupid question, i dunno....thanks.

 

It lets you fine tune the fuel/air ratio, which let's you squeeze out more power.

 

Stupid...eh...borderline.

It's an air flow and fuel flow piggyback computer. With better mods you're going to need more of both air and fuel. The AFC piggybacks between the ECU and the engine itself and intercepts the AF ratio signal and has the ECU adjust the mixture of both, dependent on how much of each you need. Things like camshaft upgrades or even timing advances and turbos (useful but not necessary) need the AFC in order to function properly. Not useful until you have mods beyond the basic bolt ons. One more thing to mention: don't tune one of these unless you know what you're doing. With it, you potentially have the ability to cause your car to run uber-lean and turn your multi-piece engine into a slab of iron and aluminum.

 

thanks.

 

It'd be useful to also have a monitoring device such as a exhaust gas temp guage, pocketlogger, or a/f 02 voltage.

 

Yeah well, any lightly modified car surely isn't going to need those things. EGT is also really only useful for a turbo to monitor/avoid a lean situation.