Quote:
Originally Posted by MetroMPG
I'd argue that tank to tank testing is madness! Way too many variables.
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? I'm not saying tank to tank; I'm saying over a few to many tankfuls, say 400+ miles. I don't know what variables you'd be worried about, and of couse it would matter what you are testing and how large a delta change.
For something as substantial as the huge cardboard airdam results would be concrete; A B A tests work well here. If you are trying to measure something down in the noise, well, I'd argue you would have a hard time telling on the street anyways, and long-term averages are the only thing trustworthy without sufficient environment control.
Testing is tough to pull off. Cars have a crapload of variables. Maybe I'm spoiled with southern California sea level flat highways and narrow temperature and humidity range.
I wouldn't attempt to measure (random example) with/without side mirrors Cd; it's too small. Big airdam and tail? I better see a measurable result. Talking street car; if I was racing with a super slick car and a budget, more is possible obviously.
I see a lot of threads on this board making claims that I don't see evidence for. When you're measuring incremental changes that amount to a few bare percent, yeah, it's truly tough. But we need some sort of reliable -- if insufficient resolution -- tests to back up claims.