Not by myself, but I know that Vesa Mikkonen http://ekomobiili.fi/Tekstit/english_etusivu.htm in Finland has much less emissions on woodgas compared to petrol (with carburetor and without catalytic converter).
Try the water drip. According to Don Mannes, it is a remarkable plus in power.
Also Johan Linell in Sweden did tests on his old Volvo with good results. Test results are shown 8:00 minutes into the video.
Oh, and don’t forget about Wayne’s results from Auburn university.