Tuning for fuel milage? Options

[AWD DSM 1]

Hypothetically, would it be possible to tune a car to get better milage than what it came with from the factory? Lower the boost, take out some fuel?

[NOMIEZVR4]

Since we are on the topic of gas mileage, I may as well ask a question. I have a mildly modded 1g DSM.

-K&N
-Intake/UICP
-Spearco SMIC
-MBC
-Walbro-255
-Exhaust-not installed
-DIY ported 14b/mani/o2 housing


I will swap out the 255 with a 190 sometime in the near future because I dont have the $$$ for an AFPR and I dont plan on getting any major mods other than a mild set of cams. When that is done, I want to throw on a 2g fpr to get the most out of the 450cc injectors.

Now here is my question. I know that by increasing the base fuel pressure a rich condition will exist at WOT because the 1g ECU still thinks the base FP is at 38.5psi when it will be 43.5. But while cruising, will the ECU be able to compensate for the higher pressure via the 02 sensor? I really would like to raise the pressure, but I dont want to do it at the expense of gas mileage. What do you guys think?

Also, while im at it, since the fp will be higher, I will hack the MAS to lean out the mixture some more and have better combustion

Nomie