View Full Version : Yet another fuel economy post

Don Horner
09-04-2008, 05:51 AM
I just returned from an approximately 3,000 mile trip from Florida to Western Pennsylvania and back. The route was varied, some interstate driving, as much side road driving as feasible including small towns and many traffic lights, mountain driving in West Virgina and PA, a fair amount of city driving as we were exploring haunts from our younger years (we were up there for a 50th class reunion).

Some months ago, I posted that I was going to hold to 55 mph for fuel economy reasons. I did that on this trip. I think my total miles above 55 mph might have been 10 to 20 miles, mostly to pass someone going 54 mph.

I have a scan guage and my numbers are as reported by it. I religously enter every fill up and have checked the scan guage against traditional math to figure mileage, and it is very accurate. Mostly I keep the scan guage on the "tank" setting because that is the best indication for overall mileage.

I averaged between 24 and 25 mpg in the mountains, and between 25 and 26 mpg in the flatter Southern states. I saw mileage as high as 27.6 on one fill up where I had only a short, flat ramp from the filling station to the Interstate, and flat terrain for hundreds of miles with no variation in speed.

The Sprinter is an '04 long, tall T1N titled as an '05 Leisure Travel Van, fully loaded as an RV conversion, with more "stuff" than you can imagine tucked into every nook and cranny. I have never weighed it but would not be surprised to see it near 8,000 pounds.

My calculations over the past several months indicate that every 5 mph increase in speed costs me almost 10% reduction in fuel mileage. We had one fairly long interval at a speed limit of 45 mph and the mileage went up to over 28 mpg average for that tank. I switched to "current" view, and saw an approximate average of over 30 mpg.

After one long stretch in southern WVA on I-77, I was enjoying about 27.6 mpg until I had to stop at two toll booths. Traffic wsas heavy and I had to accelerate pretty hard to get bak up to 55 mpg and get out of other people's way. I watched the average for that tank drop quickly to about 25.3 -- a 2.4 mpg drop just from two hard stops.

We had no problems traveling at the reduced speeds -- I just drove my "race" and let everyone else worry about how to get around me. They all managed to do so with no apparent problems. There were a few idiotic drivers who tucked in behind me and tailgated me so closely I thought they were hooked to my tow bar; apparently they thought they could intimidate my cruise control into going faster...:crazy:

The bottom line is I thought the results were cool enough that I have no plans to drive any faster.

Altered Sprinter
09-04-2008, 07:15 AM
Well Don you actually got to see the scenery and I guess Bonus! You enjoyed it. Your fuel average seems OK for an RV loaded but surprised you managed 30 MPG at the lowercase end of 45 MPH :clapping:
considering your at least running 7000LBs without additional add-on's like the DW:smilewink: food water etc. Congratulations it's nice to see a positive happy post,and a happy camper too.

09-04-2008, 02:53 PM
I run max 60 indicated (56 actual) and have installed a small Xenon strobe on the back door (off the license plate bracket) to warn all that I'm going slow. This gives everyone plenty of warning and they pull out to pass much earlier than without it.

09-04-2008, 05:30 PM
.... and have installed a small Xenon strobe on the back door (off the license plate bracket) to warn all that I'm going slow.
Cool ...... I love it :thumbup:

Great post on the mileage info BTW. :clapping:

09-04-2008, 05:37 PM
Talkinghorse43's original posting with the strobe link is here (http://sprinter-source.com/forum/showpost.php?p=23012&postcount=15).

The website's been reorganized since then.

This is the strobe (I believe, but I'm sure talkinghorse43 will correct if I'm mistaken).



Don Horner
09-05-2008, 02:56 AM
I hadn't thought of a strobe; sounds like a good idea. I do wish there was some way I could hook up my scan guage to a larger LED read-out in or on the rear window, showing the mileage I'm getting. That way, not only would people not be angry with me, but would probably give me a thumbs up! Or, maybe I'm mistaking some other digit for a thumb?

I also thought about a simple sign for the back, something like,

"I'm getting
more than
25 MPG
by driving
no more than
55 MPH"

By the way, I set the cruise control at an actual speed of 55 mph as indicated by the GPS. It's an indicated speed of about 58 mph.

It's very relaxing. I got shot by radar 3 times that I know of, each time by an officer standing outside his car and aiming the radar gun at me. Two of them had looks of frustration, the other waved.

09-05-2008, 05:42 AM
I also thought about a simple sign for the back, something like .......
Heheheh ...... I love that one too ! :cheers:

This isn't exactly related to staying safe while driving at 55 mph, but it is a safety accessory that I added after a friend who has it on his Sprinter told me about it - I think it's a great idea:

Brake Light Flasher (http://www.signalz4u.com/)

It's a simple little electronic device (three wires) that you hook to your center high-mounted stop light - when you step on your brakes it flashes the center high-mounted stop lamp 3 times at 1 second intervals ..... before allowing it to illuminate steady/solid. The cost is like $22 and the install can be done in about 10 or 15 minutes. Legal in all 50 states.