On Wed, Jun 11, 2008 at 9:46 PM, Von Fugal <[EMAIL PROTECTED]> wrote: > Just a note, turbo chargers and superchargers do NOT increase > efficiency, only power. *charged vehicles generally get lower mpg.
Not true. Power and efficiency are the same thing in a different context. When you have a charger making a bunch of boost and the pedal is all the way to the floor you are definitely making more power than if the same engine was naturally aspirated (NA). In this case the fact that you are getting more boom for the same amount of gas is academic because you're basically pouring gas out on the ground. The reason charged vehicles get lower mpg is _not_ because they are less efficient. It's because the people who drive them have heavy feet. More air means bigger boom. I'm sure we all agree on that by now. Bigger boom means less gas for the same amount of power. So when your foot is not all the way to the floor you do indeed get better efficiency and therefore mileage. More power == more efficient if you're not pouring gas out on the ground. My Honda Fit, which gets better mileage on the freeway than my old Civic did, gets significantly worse mileage around town. Why? Because it has less power. Less power == more effort to do the same amount of work. Stick anything on my car to increase it's power and my in-town mileage will go up (to a point) because it takes less effort to do the work. It takes less effort for me to lift 50 pounds than it takes my wife. Because my muscles are larger and generate more power than hers, that same 50 pounds is less of an obstacle and I can lift it and put it back down many more times than she can. I'm sure I could come up with more examples, but I hope we're all getting the point. I spent a good portion of my younger days as a mechanic, both in the Army and the civilian world and believe me, I have played around with _lots_ of engines. There is a reason that nearly all military diesel engines have a turbo attached to them, and that reason is not solely for max power. Our ambulance HMMVs (had turbos) when I was in the Army had a larger "effective range" than the NA HMMVs did. One last time, more power == more efficiency. -- Alex Esplin /* PLUG: http://plug.org, #utah on irc.freenode.net Unsubscribe: http://plug.org/mailman/options/plug Don't fear the penguin. */
