I know this is a topic that won't die
but it caught my attention, so here goes... After spending a few quality hours reading up on the topic,
here's what I gathered:
Despite some amazing efforts to test it out (props to everyone doing the work!!), no one really knows if it's effective. However from the little data that I came across and the anecdotal evidence I saw, it seems to me that
hatchbacks (or any rather boxy shaped tailend for that matter) do not profit from VGs and may even lose FE. On the other hand, cars with a tail-end that is just a bit to steep to keep the flow attached -
such as a lot of sedans - can benefit from the right kind/type of VG.
In
evaluating the case for/against VGs on my Lancer, the Mitsubishi reserach was of course a tremendous help as they were basically doing their research on 'my car' with only the rear spoiler being a significant difference.
At the end I decided to go ahead and order a set of
Vortekz for my Lancer. Here's my reasoning:
- As the Mitsubishi research showed, there can be a drag reduction.
- The Evo wing that was in use in their testing is meant to increase downforce (which it did, as the testing showed increased downforce from the smoother flow). The spoiler on my OZ however is an optical gimmick, not a working wing, thus smoother airflow around it shouldn't increase drag.
- Even if they don't work, they don't do any FE harm either, at least I have not seen anything that would indicate that.
- At the very least I will have better visibility during rain as I have no rear wiper. Worst case scenario, I will see a small advantage even if they don't do anything for FE. And I rather like the look
I did have one question:
Vortekz.com
recommends installing some of the VGs at an angle, can anyone fathom why? I could not find any good information on this topic and from the Mitsu reserach it seems to me that the ideal VG is a delta shape parallel to the airflow
(I did e-mail them about that but have no answer yet)
On another note, I would love to do some
A-B-A testing if I can find the time, however I do not know of any flat and straight highways in the Baltimore/Washington area that would lend themselves to do the testing. So if anyone familiar with the area can recommend a spot (within a reasonable driving distance) I would be very grateful.