RPM's & MPG

[pesticidal]

I've yet to fill my second tank on my '05 S, but the 1st tank with a lot of spirited driving got my 21+ mpg.

I set the cruise 60 mph with no wind, and re-set the computer. After a couple miles, I was running 29 mpg.

[ProjectM96]

For some reason, when I do lots of spirited highway driving on my 4 hour trips often going what is considered a very unefficient speed, I average 28-29mpg in my tank.

But mixed city/highway spirited I average 21-22mpg.

[Homeboy981]

Originally Posted by ProjectM96

For some reason...often going what is considered a very inefficient speed, I average 28-29mpg in my tank.

But mixed city/highway spirited I average 21-22mpg.

I'm with you almost EXACTLY! I am getting 28 on highway at 70-80+ and in the city it is right around 22 because it is hard to drive like the good doctor ordered in traffic!

All in all….pretty darn good for a sports car! Especially compared to those hungry V-8s.

[southernstar]

One can't expect the gearing on the Boxster to be the same as a Camry for several reasons:

1. The redline on the 2.7, at 7200, must be about 10% higher than the Camry.

2. While 5th gear is, in fact, overdrive, nevertheless the intention on the Boxster (as with any performance car) is to keep the gear ratio spacing closer - ie., 'close ratio', so as to provide more seemless and balanced acceleration through the gears. The Camry, on the other hand, is more concerned with acceptable performance but higher fuel economy numbers on the highway that will appeal to most buyers.

3. In addition, the advertised top speed is more important to many Porsche buyers than the advertised fuel economy numbers. Increased speed increases drag and to achieve higher speeds for a given car, it is critical to have your maximum horsepower on tap as you approach the potential maximum speed. Since peak horsepower on the engine in the Boxster is very high up in the rev range (and drops only marginally thereafter until redline), it has a higher top speed than if the car was turning only about 4800 RPMs at, say 135 MPH. Were that the case, it is likely that the car would not have enough horsepower on tap at 135 MPH to overcome the aerodynamic drag at that speed and higher speeds would likely be impossible.

4. The Boxster engine just sounds so sweet at higher RPM's!

Brad