[jcp123]

I had been driving my Mustang for a year, getting disappointing numbers. I always keep track of fuel economy, even though I am resigned to the fact that you don't drive what I do for fuel economy. Still, a few things helped me along.

1. The carburetor. It was tuned on the safe (rich) side when installed. The black soot that collected at an alarming rate on my tailpipes was my first indication; carbon holding valves open was the final straw. One stage leaner on my cruise metering rods did the trick, I now have far less soot buildup, no carbon problems, improved FE, and all while retaining driveability. I also reset my lean-best idle, and it's a smidge leaner than before.

2. Driving style. I've hypermiled other cars before, so I'm no stranger to technique, but figured on a carb'd car with no aerodynamics and an auto trans it was a lost cause. I realized I was looking at it the wrong way; poor aerodynamics, for instance, mean that slowing down can net great benefits. My commute consists mostly of 50 mph routes, with one section at 45 and another at 55. I slowed down to 40 and redoubled my efforts to be smooth on the throttle and take advantage of any coasting.

3. Tyres. I had them up to 35 already, which was the sidewall max of my old tyres, and just recently jacked them up to 38psi cold on my new Goodyears with a 44psi sidewall max.

Results? I went from high-13's/mid-14's to over 17. In the last month, every tank has been over 17mpg (except for two tanks, while travelling, with extenuating circumstances - I filled up quickly after so they wouldn't "contaminate" a longer tank), with several over 18 and a first tank over 20mpg. My commuting tanks, the ones that really count, are consistenly in the mid 17's now. Assuming a conservative 3mpg gain (I'd say it's closer to 3,5), that's a 21% improvement. Hooray!