Metro XFI Cam Advance Experiment
Well, I just finished with a fairly long experiment. I have been moving the cam timing around on my car to see what effect it has on mileage. Keep in mind that I have shaved the head .040" so the car cannot tolerate as much advance as when it was stock. I have tried from -2 to +11, and for each of them I ran the maximum ignition timing that I could run without knock. I gave up trying to do 2 tanks each due to the weather, and my having to drive less to work means that it takes me 2-3 weeks to run a tank of gas out now so it would be almost a year to do this test the long way. I did short tanks of at least 100 miles and filled the tank to the top with the car sitting at an angle to keep the air bubbles out.