Hi,
Kind of a Looooong Post!
I just joined the site. I have a 21' Class C based on a 1996 Ford E-350. Always been wanting more MPG, just like everyone. Oh, by the way this 1996 was one of Fords "got ya" models because it really a 1995 sold as a 1996. No way to use a scantool program plugged into the under the dash connection for OBD-II fault checking. The connector is there, but the E-350 was made with some OBD-I setups and some OBD-II and I got the one with an OBD-I wiring. So, any check are made the old way, pencil and paper. 351W engine.
Anyway, about the best I've ever gotten for gas mileage was maybe 9 MPG. That was driving on the flat with a good tailwind, something we never seem to encounter. A couple of years ago I started messing around trying to improve the mileage. Like most of the folks have said better mileage comes at a cost. Usually more money than ever saved. But, I bet the first light bulb had to cost a couple million in today's cash. I just like to tinker around and play with some ideas.
I've been messing with the water pump and the fan. Read every thing I could find about electric water pumps, high performance pumps, H-P fans and electric fans. Like everything else there were feeling for, against and not caring if any better mileage could be obtained. So, I got a cheap setup for driving the water pump by electric motor and rigged up an electric fan by just strapping to the radiator. Took it on a little cruse around town, both on the freeways and in city traffic. This was in the Phoenix area, during a mild summers day, which means it was not the normal 115*, but maybe in the high 90's. I got good mileage, but it was not a setup I'd want to head out on a month long across country trip. Fans only work hard a slow vehicle speeds and stock water pumps vary in the GPM supplied. But it was enough to get me to get a better electric pump and make a fan shroud for the fan as well as get all the supporting wiring, fuses and make time to install and test.
The total invested so far is over $500, but I'm having fun and hope my playing around gives others ideas on what to try and the cost. The electric pump will deliver about 50 GPM and the electric fan is about 2500 cubic feet/minute. I drive an 84 mile loop around the area which allows me to drive at the same speed most of the drive, unless there's traffic problems or when I change from one highway to another where I have to slow to 45 mph for about 2 miles total.
I first drove my route with the RV just as I last put it away. My best mileage at 65 mph was about 6.5 mpg. I drove it again another day at 55 mph and got about 7.5 mpg. I then put new plugs, wiring, distributor cap (other was shot), change the synthetic oil/filter and drained the transmission and pumped out as much old as I could and refilled. I also found a vacuum line totally shot and replaced that whole vacuum circuit and then went for a test drive and improved mpg by about 1-2 mpg at 55 mph. I then installed the electric pump and fan/shroud. I controlled the fan to turn on at 180*. I then went on a 55 mph drive and got 12.8 mpg. I later drove the route at 65 mph and got 9.9 mpg. I had a light rigged in to tell me when the fan was switched on also. It stayed off all the time when driving and only came on near the end of the drive when I have three traffic lights, where it cycled on an off until driving again.
Since I've started writing a book, let me give you some of the ways I measure my gas mileage. I don't depend on the gas pump clicking off. I got a hand pump, one with a clear plastic hose and then a hand squeeze bulb and the another clear hose. I put the intake end through a COPPER (no spark from copper) and placed the two ends even with each other and taped the upper end to keep the hose from slipping. I fill the tank until the pump turn off, then check the level by inserting the pipe/hose into the filler until it stops. On mine there is a bend where it stops every time. I pull the setup and check for gas. When I determine the end is in gas, I hang up handle, print out a receipt. I then pump the few amount of gas into a measuring cup and get a reading on the amount, usually 5-10 ozs. I write that on the back of the receipt and pour the gas back into the tank. I write down the mileage. I use both the units mileage reading and I carry a portable GPS too. Then when I get home I do the math.
When gas was $4 to $4.50 a gal. the payback would have been quicker. Gas here today was $2.43/gal. I'm still going work on this and the aerodynamics with maybe an air dam and efforts to place deflectors from the cab to the outside edge of the RV box area. Might try some exhaust stuff, but got to watch for the EPA dogs which I have to go through every year. Gas prices may go up again some day and like I said I have time and like to putts around in the garage. I also have a MAP sensor to play with on the O-scope. Fords have a weird MAP as you can read in the tuning post.
For the guy asking about the torque converter lock-up here's a link that might help:
http://www.fullsizebronco.com/forum/archive/index.php/t-87296.html
Here's the link to the water pump:
http://www.jegs.com/i/Meziere/680/WP312B/10002/-1
Here's some other "mileage" extenders I may look into:
http://www.fuelsaver-mpg.com/tuning-for-mileage
Not the stuff they're trying to sell, but some of the tune-up ideas!
Look here for the MAP sensor info:
http://www.aa1car.com/library/map_sensors.htm
I have other links for MPG monitors (really easy, just have not built mine yet....got the parts) and other sites with regular car mileage postings that can help.
Sorry for such a long post, but hope some may like to read about some of my MILEAGE ADVENTURES.
