May I suggest that more clean flowing air on a rear spoiler is no necessarily a bad thing. I'm not suggesting that having a spoiler promotes FE in all cases. But rather that a properly designed and fully functional spoiler could potentially reduce turbulence behind the vehicle. Once again, this is something that Mitsu proved in their PDF. I will not deny that the Lancer EVO MRs rear wing is designed primarily for downforce. But there are many other examples of OE spoilers that could truly benefit from Vortekz fins(ie:Honda Civic Hybrid, VW Jetta TDI, BMW M3, ect.)
__________________ 1993 Volvo 240 Wagon - 323k miles (awaiting recommissioning) 1999 Audi A6 Avant Quattro - 149k miles(the NEW daily driver)
Reduced turbulence = reduced drag, so long as airflow is not being turned into down or up force. The question is what happens to the wake behind the car. My bet is that most sedans and coupes with similar rear profiles will benefit from cleaner flow over the rear of the car.
Additionally, I would argue that the spoiler on the rear of the 6 is intended to be marginally functional, but only at higher speeds as seperation off the window tends to increase. So it may actually be of benefit to remove the spoiler. Only testing can really tell there.
so I suspect that yes the Vortekz Generators do help in FE.
Well, if you don't even know what your highway MPG was before the VGs, in a similar condition, with similar driving style, you can't confirm VGs help on your car more than just for cleaning the back window.
The only thing you can conclude is.. you're happy with your MPG the way the car is. (I guess you could check fueleconomy.gov to see what FE people report and see if anyone matches the same driving conditions to get a ballpark idea if aero mods have helped you).
For example, my unmodified del-sol surprised me when I hit 49mpg highway (with a traffic jam in between!) even though there's no aero mods. I attribute this to my changed driving habits.
That's why semi-controlled testing is the best way to see if something works by eliminating some of the variables that can skew results. I do my tests on the same stretch of road, 3x north and 3x south with and without the modification (12 total trials) at the same period of the day after warming up the engine by running a 15+ mile route just for consistency. If I was really serious I would also take into account the amount of gas for weight fluctuations.
With the scangauge I also try to record results at a given TPS (since I don't have cruise control) and at a given MPH on the same stretch of flat road while watching out for other cars to avoid more variability.
I know they work through my own testing . I have been running them on my swift for about a year. Great testing pics I should have sent in pics on how I tested my generators. And yes they do work on hatch back cars they just need different placement on the roof....My testing was done in the car wash like my own wind tunnel.using the water spray as my test just like on the street in the rain..It really worked!!!!!