Engine Performance

Your asking for the impossible. Adding power requires more fuel. More fuel equals worse MPG. Your best bet is be sure the air filter is clean, there are no restrictions in the intake or exhaust. New plugs and plug wires might not hurt either depending on the miles.

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Look up "Ultra Power" On IRV2 website. Brazels in Washington And Redlands in California install these kits. Bill

donn0128 wrote:
Your asking for the impossible. Adding power requires more fuel. More fuel equals worse MPG. Your best bet is be sure the air filter is clean, there are no restrictions in the intake or exhaust. New plugs and plug wires might not hurt either depending on the miles.

I'm with donn. It's one or the other, performance or mpg. Anyone telling you any different is lying or trying to sell you something.

The most effective way to increase milage, assuming nothing is in need of repair, is to slow down. You're battling a whole lot of air resistance, and that increases with something like the cube or the fourth power of speed. (Of course, there does come a point where slowing down more does not improve mileage. At the extreme, your mileage is zero if you aren't moving.)

If there is something in need of repair or replacement, fixing that is of course a no-brainer.

The best you will do is slight. However, keep things CLEAN. Oil, air filter, good plugs - will do you very well. Tire pressures correct will also do you well. I prefer to run a bit of Marvel Mystery Oil in my fuel to clean/lube the upper cylinders valves. Also remove dead weight (keep things physically clean and remove items unused).

Headers, FF muffler, CAI, advancing the timing, computer mods like Ultra power will all increase performance but unlikely to increase MPG. Headers, FF muffler, CAI, advancing the timing increased my performance as measured from 40-60 mph. As others have said wires, plugs, and general tuneups help also. My baseline performance when I first bought the MH was 22 secs. After tuneup it dropped to 19 secs. Headers, FF muffler, CAI, advancing the timing further reduced the time to 12 secs and added about 80 hp. An 8.1 engine is more efficient the the older 454 so you will likely get about half the increase of HP and performance with these mods. The only increase of MPG that I saw was adding a vacuum gauge. By trying to keep the gauge above 10 ins of mg, I saw an increase of MPG from 8.5 to 8.7. Good luck in what ever you decide to do.

Drive slower will improve performance and efficiency.