MPG Gauge

[LSC9901]

I am somewhat interested in getting a MPG gauge for my RV. In my search here I have found a system that will work on 1996 and newer RV's. Mine is a 1984 so that system is out. Many have stated that the pencil and paper method works just fine. My main interest is determining the optimal speed at any given time to get the best MPG's. Yes for the most part it'll be a toy but since having a built in one in my car I have seen a change in my personal driving habits. Does anyone have any recommendations for a value priced gauge that will work in my "Vintage" RV?

Thanks

[baraff]

Most of the 1996 and newer vehicles use OBDII, earlier vehicles do have the computerized electronics capable of supporting a mileage computer. However a search on the J.C. Whitney site turned up this: Digital Fuel Mizer - JCWhitney
Maybe this would work for you?

[Lokahi117]

Worked great and I got fairly scientific about it.
I filled my gas tank up til the pump stopped. Then recorded my mileage (since my old girl lacks a trip odometer, though you could use a GPS ). Then I drive on this trip about 120 miles going 55, stopped, filled up, then divided the miles I drove by the gallons it took to fill me back to full. The resulting number was my mpg going 55. I repeated this for each speed sixty, sixty five, seventy, and so on. It was really helpful.

[bicklebok]

Quote:

Originally Posted by Lokahi117 Worked great and I got fairly scientific about it. I filled my gas tank up til the pump stopped. Then recorded my mileage (since my old girl lacks a trip odometer, though you could use a GPS ). Then I drive on this trip about 120 miles going 55, stopped, filled up, then divided the miles I drove by the gallons it took to fill me back to full. The resulting number was my mpg going 55. I repeated this for each speed sixty, sixty five, seventy, and so on. It was really helpful.

Which speed did the best for you?

[Lokahi117]

It was as follows (though this is my 79 Chevy Scottsdale not my RV)
But it was and still is
55= 17.38mpg
60= 15.61
65= 14.49
70= 13.72
75= 12.8
This is a half ton Chevy with 350, 4 barrel edelbrock carb model 1806 jetted for maximum fuel efficiency, th400 3 speed automatic transmission
But I do find with carbureted engines 55 seems to be the sweet spot for fuel as the coefficient of drag increases exponentially as you increase speed.

[Nick-B]

That JC Whitney thingy is interesting but only monitors acceleration and deceleration forces which would be sorta-kinda helpful in maximizing fuel economy.

Your Class C Ford is an "old school" chassis so why not use an "old school" tool - the Vacuum Gauge. That used to be the main add-on people would use to help with maximizing fuel economy. Probably find one at your local auto parts store.

Don't forget to keep your eyes on the road!

[GOLDWINGER2]

Vacuum gauge and tachometer. Pencil and paper.
J

[Possum]

My unity has a chev small block 400 and it gets its best mileage at 55 per. I can seriously say that at 70 per you can watch the fuel gauge dropping quickly.

I should also note the vacuum gauge make it much easier to see where I was getting better economy driving the old girl. It slowed climbing hills but saved me gallons as I progressed.

Dennis

[Ragingbull]

Can't beat a vacuum gauge. Any other electronic device might give you a rate of miles per gallon (or in my case gallons per mile) but I've yet to see any that are accurate for older vehicles. Miles per tank full are about the only way I know of to gauge overall mileage.

[tekrsq]

Somebody explain the vacuum gauge. Looking for low pressure ? Where's the best place to hook it up ?

[awarnes]

Don't waste your money. Use the old paper and pencil. I have a vacumn gauge on my 87 Allegro and it isn't even close. Anything that is added (gauges, especially to an older vehicle) is a waste of money. Go fill up and drive it in some different environments and then track you mileage. Its how we did it before computers. Still works today. Even though my SUV has all the bells and whistles I use the math.

Good Luck
Arnold

[GOLDWINGER2]

Quote:

Originally Posted by tekrsq Somebody explain the vacuum gauge. Looking for low pressure ? Where's the best place to hook it up ?

You want to maintain the highest vacuum reading possible.
Hook it up to manfold vacuum outlet.
J

[Possum]

Quote:

Originally Posted by tekrsq Somebody explain the vacuum gauge. Looking for low pressure ? Where's the best place to hook it up ?

My unit ($10.00 at wreckers) is sitting on my dash right in front of me so I just glance down to see whereb the needle is indicating. The gauge has a white area, (Idle) a green area, (best mileage) a blue area, (not so good mileage) and a black area. (terrible mileage) The idea is to attempt to keep the needle in the green area. I noticed when I hooked mine up (rubber hose through dash to vacuum manifold near carburetor) I was consistently in the blue area which indicated I was not getting good mileage. After about an hour driving through our mountainous terrain I can now keep the indicator either in the green or if in the blue close to the green. It does slow you down a tad as speed doesn't necessarily equate to great mileage. I am tending to get about an extra 20?? miles to the tank and as we keep better records I will know better how successful I am. DW loves to calculate mileage as we go and she agrees that we have improved since the installation of the vacuum gauge.

[LSC9901]

Ahhhh yes. This what I was looking for. I knew something like this used to exist but I just couldn't remember what I was looking for. I guess my brain is now in the "Vintage" category also. I will just assume that the installation instructions a relatively clear. I'm not much of a mechanic although I'm always more than willing to jump in. Obviously with an '84 RV I've been initiated into the world of mechanics.

I've found all the parts needed at Advance Auto Parts for about $30. This includes the gauge, 6' of tubing and connectors and a gauge mount. It is the SunPro model. Has anyone else seen it for less anywhere? After all .... this whole thing is about conservation !!!

Thanks again for all the help ... as usual, everyone here is just fantastic.