Quote:
Originally Posted by ChazInMT
3% improvement based on "I'm getting better mileage."
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Sure, why not ?
If you change something and you get better FE, see previously impossible MPG values, then the change has had some effect. Like it or not.
Is it 3% ?
Probably not - that'd mean about 6% drag reduction, which is fairly massive.
But it's clear that the flow pattern HAS been changed by adding the VGs.
It's at the rear, so it'll likely bring something, too.
I've had tiny VGs on Hägar - mirror and A-pillar.
Merely 1mm or 1/25th of an inch high, but they also changed the flow pattern on the side windows and quietened the A pillar noise .
Nothing quantifiable in the MPG department though.
They were too small to do anything at the rear end though - where I had them around the entire rear hatch (station wagon).
VGs work.
They wouldn't be on gliders if they didn't.
It's just a bit tough to get them positioned so they really work for you, and to quantify it.
The traditional spots to put them obviously didn't work here.
Moving them to be a tad ahead of the separation point did work - which is exactly where they are on gliders ...