Hi Y'all,
I don't recall when or how I ran across this site, but I've lurked for a while and finally decided to join yesterday.
I have been tinkering since I was in grade school -- I'd play with my toys, then take them apart, as that was usually more fun! I was a plastic modeler (mostly 1/48 WWII-era aircraft) until I started driving my '57 Chevy in high school, at which point I went into gearhead mode! My grandparents were the original owners of the '57 and it's still in my garage. I won't list the plethora of performance mods, but I will say that it can twist driveshafts and shatter differential gears but still get 18 MPG on the highway. Yeah, that ain't great, but...
The 2nd car I modded was a '72 Porsche 914, which I no longer have. Even with larger pistons (1.9L), a 270-degree cam, and dual 36mm 2-bbl Dellortos, it got 45 MPG on the highway from Sacramento, Ca to Spokane, WA. Some of that great MPG was probably due it following my '57 Chevy which was pulling a medium-sized trailer (not drafting, though, as that made my ex nervous).
The two cars I have in my stable now are an '84 Mercedes 300td wagon and an '86 BMW 535i, both of which are at 340,000 miles and get 28 MPG and 21 MPG in Atlanta-area commuting conditions, respectively. The Mercedes, which I've had for about a year and a half, is pretty much stock, except for an electric fan/pulse-width fan controller in place of the clutch fan. I did cut one coil off the front springs and install thinner spring pads, but that was not for aero -- I got tired of folks asking why it was as high as a truck! My driveway was clean until I got the Mercedes, and now it looks like a Dalmatian.
The BMW, which I've had for sixteen years, has been changed from an automatic to a 5-speed, the diff is now a 3.46 limited slip (was a 3.25 open), has a chip, plus many suspension mods and larger brakes. Both of my sets of wheels for the BMW (street and track) are lightweight, but that is mainly for performance and handling, not economy.
Interestingly, changing the tranny, chip, and diff had no noticeable effect on MPG.
I've never checked my MPG when doing this, but it can't be good...
I obtain most of my MPG gains by driving technique. I'm able to pace lights pretty well and know which lanes to be in (and not to be in) at various intersections so I can stay moving. I also don't use A/C too much, either. It also helps to leave home early in the morning and avoid the stop-and-go on the highway.
Finally, I'm an Aerospace Engineer by degree and am a Systems Engineer/Operations Analyst at a defense contractor. Besides inhabiting vehicular message boards, I like photography and drinking beer!
Regards,
Shawn