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Old 12-25-2014, 02:11 PM   #1 (permalink)
Alternative Fuels Addict
Join Date: Nov 2014
Location: Arkansas
Posts: 38
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Efficiency nut for 35 years, now into biofuels as well

Long time lurker, first time post. As a matter of introduction, I've been into fuel efficiency since the late '70s and the second oil embargo. My first vehicle was a '69 Ford van. I converted the 240 inline six with 3 on the tree to a 302 V-8 and a C-4 auto. When oil prices skyrocketed in '79 while I was in college, I started looking at ways to increase efficiency. I was running longhand cost-benefit analysis of modifying for economy. Intake, 4bbl carb, headers, larger duals... yes, more performance but better economy when drive correctly. My goal was and still is a 36 month payback.

Back then I had added a vacuum gauge and drove by it religiously. In '80 or so, I even added an aftermarket computer that was supposed to give instant and average mileage. High tech for back then! It looked neat with the blue LED readout and backlit numeric keypad... but didn't work that well.

Now, my main ride is an '02 F-250 with the 7.3 and 3.73 rear end. New, I got 19.5 to 20 mpg with a high of 23. These days, even with 335,000 miles on the clock, I still can touch 20 mpg if the conditions are just right but average about 18- 18.5. Even running on free fuel, I check my fuel mileage every tank.

For over a decade I've been running used cooking oil (heated two tank system) as well as some biodiesel and veg oil blends. I hope to regain some of that fuel efficiency loss when I replace the exhaust up-pipes, rebuild the turbo and install a turbo back 4" exhaust. No chip... but someday. Living in the south, I'm going to delete the EBPV (Exhaust Back Pressure Valve) which closes off the exhaust at idle to warm up the engine when cold. Will switch to synthetic in the diff, too. Parts bought, just waiting on me to start wrenching.

Next in line is my '95 F-150, 4.9l six, 5-speed OD Mazda trans and a high 2.xx ratio rear end. I have no idea how many miles are on this truck but I get 15 mpg around town and 19 if I behave on the highway. For contrast, my brother drives it and it gets 15 mpg on the highway. The nut behind the steering wheel is the biggest variable.

My plans for this truck include a wood gasifier and rebuilding the engine for higher compression. The mods needed to optimize running woodgas are the same for straight alcohol... raise the compression and bump the timing. My goal is to have this truck run exclusively on fuels that I can make, namely wood and straight alcohol. Just for the record, I detest E-10.

While my brother needed to use my F-150, I bought a "beater" that has turned out to be a keeper: '82 VW Rabbit diesel, 1.6l, 5 speed, naturally aspirated. 145,000 miles but it hasn't been driven much in the past decade. Slowly but surely, I'm seeing the economy come back from the high 30's to 45 mpg on the last tank.

I run my company off the grid using a diesel generator for power. I have a small amount of solar power but find it doesn't meet my 36 month ROI mindset. I have an '85 F-350 flatbed with the 6.9 diesel, 4 speed and what must be a 4.xx rear end. No tach but that thing is screaming at 65 mph.

Just recently, I was given a Perkins 4.236 diesel that for the past 30 years was in a late '70s Ford F-100 4x4. It came out of a mid-'60s vintage Massey Ferguson combine. Top end in the pickup wasn't much but it got 26 mpg. The owner swapped the 236 cubic inch/3.9 liter 4 cylinder diesel back to a gas burner 300 six cylinder and gave me everything related to the Perkins... radiator, cross member, bell housing and adapters to run a Ford transmission. I'm toying with putting that diesel in the F-350 (with a body swap for something out of the '40s or '50s). The mpg-nut in me is thinking about a Ford Ranger, Explorer or Bronco II.

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