| [GMCnet] 15.875 MPG [message #246027] |
Tue, 01 April 2014 11:59  |
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ljdavick
Messages: 3548
Registered: March 2007
Location: Fremont, CA
Karma:
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Senior Member |
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I've been tinkering with the coach to try and maximize efficiency. Here is what I've done, and the measurements from our trip to So. Cal today.
- 16.5" Firestone Transfoce tires have been likened to wagon wheels so I thought why not go to maximum inflation pressure. My Harbor Freight compressor won't go past 95psi, so that's where I have all six tires set.
- removed spare tire as the added weight is unnecessary. I have AAA.
- fuel delivery - it dawns on me that very little fuel is burned during periods of vapor lock. I have coiled a length of PolyArmor around the exhaust pipe and then to the carburetor.
- the carburetor is the single biggest fuel waster. It allows too much fuel to go into the engine. I disconnected any linkage to the secondaries and goobered a liberal amount of silicone around the butterflies to seal them off.
- I've eliminated 2nd gear.
- with both hatches open and both roof fans on high I have the cockpit windows open for airflow. The woosh of air is positive proof that this is the future of efficiency. When I return home I will affix a whole house fan in place of the rear window.
- airflow through the radiator has been a big topic here. Baffles and air dams help, but really it's the radiator that is the problem. I've blocked it off entirely.
- Rain-X also reduces friction over the road. I applied 4 coats to the entire coach. FYI - don't put it on the entry step or the toilet seat.
- it is a fact that air is thinner, less dense, at altitude. I've inflated my rear bags to maximum.
- it's a small step towards a hybrid but I connected the Onan 110v to the alternator and starter motors through a switch. This way I was able to gain horsepower by running them as motors to add power to the 455.
With all of these improvements the coach is a dream. I liken it to the feeling man had when he first flew, skated on ice, or skied on water. The coach had abundant power and though I tried to keep it under 70mph I wasn't always able to do so. Fuel economy is nearly 16mpg, which is the theoretical maximum for a 455 at idle going 60 mph.
I'll mark this historic day on my calendar and expect that forever April 1st will be celebrated as, oh, you've already figured it out…
Sorry.
Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, CA
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Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, Ca
Howell EFI + EBL + Electronic Dizzy
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