When you understand the basic design differences between a powerful car and an efficient car you will understand my statements.

A good example is a 94 Honda Civic VX and the same 94 Honda Civic SI. One is designed for power and the other is designed for efficiency. Compare the differences in fuel economy.

In 1950 Alfa Romeo built a 1.5 liter engine that produced 390 HP at two miles per gallon in racing trim, same displacement as my VX.

Now consider the NASCAR restrictor plate engine getting 6 MPG at 180 MPH, three times the fuel mileage on the 1950 Alfa engine. The resitrictor plate reduces the power available while increasing the fuel economy, of an engine design that has changed little in 40 years.

The lust for more power has cost us dearly in terms of oil imports, when we could have solved the imported oil problems a long time ago.

regards
gary

For a beautiful example of high speed efficiency look at the aerodynamics of Basjoos Civic CX (about 76 HP).

This is a perfect example of the solution to high speed travel with great mileage.

You can bet that the new 35 MPG requirements will place a large focus on aerodynamics as a key component to achieving the new fuel economy. requirements.

I am not an advocate of lowering speed limits. This would increase congestion on roads that are already at capacity in many urban areas. It would also increase driving time behind the wheel and more people would get in trouble because they would be falling asleep at the wheel.

The increased congestion would be directly proportionate to the increased time necessary for the same trip distance. My daughter drove from DC to Nags head once, a trip that would normally take 5.5 hours. It took 14 hours, and would have taken several more hours if the traffic was moving at no more than 55 MPH, when it was moving at all.

The days of large displacement engines are numbered, as it should be.

regards
gary

Noticed this morning that I wasn't "finding the notch" then realised I didn't have my rear vent windows cranked open... They are front hinged and stick out about 2.5 inches, leaving about 6 inches behind them in the width of the D pillar and hatch. This appears to "round off" the air path and get more behind.

Are you saying you get better economy with the rear window vents open?

Any chance you could do an A-B-A test of that?

The first vehicle I rebuilt was a 66 Chevy van. I put rear windows in it that were hinged to open out towards the side of the van.

When you opened them up and rolled down the drivers door window you got about a 20 MPH wind past you from the rear and out the window. Flick your cigarette in front of your face and it just blew the ashes right out the drivers window opening. It was almost like being in a wind tunnel.

regards
gary

Only in as far as they make that "notch" in the drag envelope at about 65mph. A-B-A is hard to do, since I only get direct mpg results per full tank and I need them for flow-through ventilation, there's no way I'm leaving them closed for a week. Owners manual recommends using flow through ventilation rather than opening front windows on highway or using A/C for economy. (Also relieves pressure at base of windshield)