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Old 07-10-2014, 02:56 PM   #22 (permalink)
wmjinman
Master EcoModder
 
Join Date: Oct 2012
Location: Carson City, Nevada
Posts: 612

Jimmy - '00 GMC Jimmy SLT
90 day: 21.18 mpg (US)

The White Gnat - '99 Suzuki Swift
Team Suzuki
90 day: 51.87 mpg (US)
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I remember an article a few years ago in Hot Rod magazine where they took their salt flats Camaro to the A-2 wind tunnel and did a bunch of testing. The hood/windshield area was one thing they played with. At one point, in a desperate "hail Mary" attempt, they made a massive fairing out of styrofoam from the front of the hood all the way to the top of the windshield, and that didn't even help.

Their conclusion was similar to what's being said here: that the "high pressure bubble" in front of the windshield seems to streamline the airflow as well as any physical object that can be placed there (besides a curved section that would move the "template" forward, maybe?)

With that being said, I still can't help but wonder if it's true, or if a hood that slopes up higher towards the back might help. I actually tried this with a '73 Riviera I used to use for aerdynamic testing. I made wedges by carving styrofoam, attached them to the hood, then made a top skin with 1/8th inch "Masonite", or "hardboard". As I recall, the back edge was about 6" higher than the hood, and I ran it all the way back to the windshield & sealed it up & smoothed it with duct tape. It was so high, I could just barely see over it.

My testing was to take it up to 110 mph on a remote, lonely road, then let it coast in neutral down to 60, timing with a stopwatch. I went both directions over the same section of road, and think I did 2 "sets", maybe 3. I also did the test without it. Result: no change. - - - damn

I also tried testing the effects of removing the windshield wipers on the "White Gnat" with the ScanGauge using the A-B-A method, and no change there, either.

Even so, I still want to think there's an opportunity to improve things here.
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