Aerodynamics acording to Myth Busters!

Bill Daniels wrote:
You guys haven't mentioned the biggie - roof racks. Removing the cross bars
from my Grand Cherokee added 2MPG. Glider pilots look at roof racks and see
open air brakes. I can't believe the number of vehicles I see in Denver
with ski racks in July.

Then, of course, you can park the truck. I understand that trucks have very
low drag when parked.

If the vehicle has a MPG computer, you can see what speed does to MPG. At
65, my Jeep gets 19MPG. At 55, it gets 24MPG. At 45, it gets 36MPG. If
you do the numbers, saving two minutes by driving fast costs big time.
Those are REALLY expensive minutes - more than the rental on some airplanes.

Bill Daniels


Can't argue against the open drag brake idea.

I have a nice pair on my Blazer.
My impression is that they are there to enhance roll-over protection.

I don't have the MPG computer, but I just drove down to Centerville
last weekend. 120 miles alnost exactly.

V6 4 speed automatic - with highay gearing, it's NOT a tow truck.
(and when I hook the boat on the back the Blazer whines and whimpers)

22 MPG going down at 75-85 mph.
26 coming back ar 65.

But about 18 around town...

Bringing the boat home from Khema - in stop and go Houston traffic -
climbing the ovepasses from a standing stop -
first 100 miles at 10 to 25 MPH took 10 gallons.

After that, at about 50 MPH I got more like 15-16 MPG.

(The boat is 18 ft long, but over 1500 pounds - plus a heavy trailer)

As they say, YMMV.

Sometimes a LOT...

Richard