76 Dodge 440 model 821F ---mileage

Although I have had my engine tuned up (about 80K miles on it), and the thermo-quad rebuilt I am still only getting about 5-6 miles/gallon.  Is there a way to get above 10 somehow?  In Montana I can hardly get between gas stations on the 36 gallon tank.

I read about a lot of the owners having an ONAN generator.  Where is this unit usually being carried on the vehicle?
Chris #3564

[susan-y]

Chris, 7.3 mpg on my rebuild, that was with some hills, freeway and back roads  (when I keep off the throttle).  Good luck in Montana with your  "miles of miles".  Couple of gas cans on the back bumper... :wink:  Sue

Thanks Sue,
Chris[/quote]

[skyloop]

Hi Chris, I hope you see this posting. I've been off line for a while. 5 & 6 miles to thr gal. seems a little poor. You did not say how fast you were driving. Milage drops very fast after 55 mph. That good looking cab overhang is one of the worlds best wind brakes.I keep hoping someone will design a snap on boot with a good airo frame under it to help that problem......My milage is a little better then yours about 8.5 at 60 to 65. I have a 440 {new} with a G V. overdrive. I just did a test myself last week. At 40 to 45 for 200 miles it was 10.5 mpg., at 45 t0 50 it was 10mpg, at a stedy 55 it was 9 mpg. As you can see wind resistance is the problem along with very poor fuel. this test was doon on flat ground with no head wind,and all tires at 65psi. Hope this helps. ....David/ Skyloop #3485   OH yes I did drive just under 700 miles!![/b]

[Horst]

the old mileage post - nowadays a VERY relevant topc!

I haven't bored you all in a while - so here it goes......

For all of us  - here are a few options cheap/easy tricks.
1) Slow down - as noted on a previous post - mileage drops dramatically after 55mph -  (0ne of the reasosn they lowered the speed limt to 55 back in the day)
As an example - at just under 55mph, in my 360, with 4 barrell Edelbrock carb and intake, with Flowmasters - I get about 9.5mpg, flat road, no wind, cool air, medium load. Best I ever got was 10.4 on Interstate 5 on a cold winter night - going to LA - pretty sure I had a good tail wind though! - and I was driving under 55. At 65mph I'm at about 7.6mpg!

2) If you can - drive at late night or super early am
cooler air=better mileage
less traffic = the opportunity to drive 55 without people crawling up your a$$!

3) Stay as "light" as you can - if you're going to a campground with hook-ups - why carry 50 gallons of water in your fresh water tank? (which weights 400 lbs) - you get the idea.

4) Keep your rig tuned well - and if you know what you are doing - fine tune the timing - you might not pass smog - but your mileage will improve

5) Keep your rig waxed and clean - air drag is reduced over a well waxed surface and ...................................I wish! - but it's good to have a clean Clipper!

Another option that costs money.......
1) Gear splitter - lots of arguments here - using an aftermarket unit (Gear Vendors or US Gear) - or finding a different rear end for your rig.
I once calculated the ROI on getting a gear vendors - and figured it wasnt' worth it to me - but I think that was when gas was still just UNDER $2.00/gal. At $4.00/gal - this option needs a serious second look - I think mileage should improve by almost 2mpg.
Note there are some pretty smart engineer types who question the actual benefit of a gear splitter - has to do with torque curves, engine strain, etc. A google search in the UseNet Groups returns lots of interesting posts.
For us - gas costs have severely crippled our Clippering  :-(

If I lived in an area where I had to climb lots of hills - I'd probably get a splitter. If I lived in a flat area and drove my Clipper more than 20,000 miles a year - I'd get a splitter.

Horst,
Thanks for the good info.  I think a new rear end is beyond my reach unless I just stop eating so much pizza.
Chris

[alhnelson]

I've got a rebuilt 440 in my Clipper and have a quadrajet carb slightly leaned out, Thorley headers, and improved exhaust - all to try to improve mileage and add a little power. I also live at 8500' elevation and typically drive between 5000' and 12,000' elevation, with constant hills here in Colorado. Just returned from a 1500 mile RT to Canyonlands, the Grand Canyon, and back through Southern Colorado climbine about a half-dozen high altitude Mt. passes. Driving speed averaged around 50 mph. I use a tach and vacumn gauge to try to optimize fuel economy but the steep climbs usually negate that effort. I had one stretch on I-70 where I got close to 10 MPG, but the overall average for the entire trip with all the climbing was 8.5 MPG. We are really enjoying traveling with the Clipper and my only wish would be to have all as is but with 15 to 20 MPG but that's not going to happen. Based on most comments, probably 8 to  10 mpg is about the best you can do depending on your location and terrain. If you are driving on relative flat roads, it's easier to slow down to reduce wind drag and still run at a good power level. This is more difficult with steep climbs as I need to try to keep the RPMs at a good point. Good luck.
Al
Member #3401