Quote:
Originally Posted by MetroMPG
It may be "real", but it's less of a "test" (less validity). I'm not sure why you would want to do this, given your understanding that "controlled as possible" testing resulted in nearly insignificant changes in rolling performance at the highest pressures. Actively driving a test route will be vastly less controlled than a coast down test, wouldn't you say?
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I'm not so sure about that, like much of what we amateur engineers do. I test fuel economy by the long course method because it has worked for me personally.
Because my test course is long, fairly flat, constant averge speed, constant driving style, is a two way course, and I start with the car thoroughly warmed, I can stay in lean burn about 95% of the time, and I get very high consistency of results. It's just a theory, but my therory is that by using a long two way course, many of the smaller errors, which would affect a short test are averaged out and down into the noise. I said it was a theory.
The negatives are that it takes time, puts miles on the car, and wastes fuel.
Here again are my mpg numbers for a recent test of some aero effects:
Baseline: 93mpg, 93.7mpg, 93.6mpg
Test results: 98.3mpg, 99.4mpg, 99.8mpg, and 99.6mpg.
I won't mention the test, I think you might remember it.
