Aftermarket parts in releation to MPG?

[4MPG]

Has anyone done a before/after of MPG after doing some of the simpler performance mods (CAI, NST pulleys, etc)? How about any cars setup kind of like the "richard holdner" car?

I would think at least the CAI/Pulleys would actually help, and maybe even the exhaust/intake parts as well?

[1NZYaris1]

From the mod's i have done. Yes i can say i have seen a increase in MPG .
So far the only real engine mod i have done is the full set of NST pullies
which lifted my KM's per tank by about 50KM's (from 610 too 660- on average)
my next mod is going to be an AFE intake (which should show another small increase) depending if i can stop myself from stomping on the gas to here that harsh intake sound.
The biggest thing about these mod's is justifying the exspense for the small
gains in HP and economy .
But any gain has to be an improvement .It's just a matter of time before it pays for it self.

[cali yaris]

most MPG gains are offset by more spirited driving behaviors.

[richardholdener]

We have done extensive R&D on mileage gains-oddly enough the most popualr mod (CAI) actually tends to reduce mileage. Hotter induction air improves mileage (but hurts power). U-Pulleys will increase mileage, long-tube headers tend to increase power but larger diameter exhuast systems tend to reduce mileage (I am speaking about cruise fuel economy as measured steady state on the freeway for instance). Light weight or synthetic oil improves mileage, a hotter thermostat improves mileage, larger diameter (or heavier) wheels and tires reduce mileage (and power). As indicated by cali-the single largest difference in fuel economy is driving style. Basically, the less you step on the gas (or change throttle angle), the better your mileage (ditto fro slower vehicle speeds)

Originally Posted by 4MPG

Has anyone done a before/after of MPG after doing some of the simpler performance mods (CAI, NST pulleys, etc)? How about any cars setup kind of like the "richard holdner" car?

I would think at least the CAI/Pulleys would actually help, and maybe even the exhaust/intake parts as well?

[Loren]

Richard pretty much said it all there.

I'll state that my lightweight crank pulley may have gained me 1-2 mpg if that. I don't think my DC header improved gas mileage any (haven't tested enough to be sure), but it doesn't seem to have cost me any, either.

[thebarber]

got 35mpg all city with the stock intake box and filter, and was consistently getting 36mpg this past summer with my intake....i dont generally drive with economy in mind...