[RedDevil]

I see a problem here.

I did not add vortex generators to my car, but I did get a better mileage quite suddenly. See my record.
Part of it may be explained by better use (or rather, disuse) of the hybrid system, though some other member here on ecomodder is adamant it can't be proven like that.
Other factors like weather - no, was consistently cooler than usual for the time of year for the last 4 months. Spring is late over here.

If a 3% improvement in fuel economy goes as proof, then it seems I have carte blanche to claim whatever I like to have a positive effect on FE.
Now what did I change to my car and habits those last 3 months?
I changed location at my office. I replaced my wife's Ipod with her music by a 32GB USB stick with mine. I got several dents and some glass damage from stone chips from our frost damaged roads. The car steadily got dirtier. I installed some LEDs, and do in fact use the headlights less now.

The gain from the LEDS is easy to calculate; it is about 1% at most. So if you want good FE, take my advice and move that office chair, enjoy your music, stone your car and whatever you do don't wash it!

I'm not saying vortex generators don't work. In fact I hope they do. But variations like these can have so many reasons that it becomes impossible to prove it with just 1 car by just keeping fuel records.
If they do work, they deserve proof that goes beyond this, and a nice picture.
This one goes without words.


(ps. did I mention change the interior? This one is bound to have some effect on FE, for better or for worse...)