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View Full Version : Thoughts on BioDiesel?



93formulalt1
09-13-2008, 01:23 AM
Well, given the hopelessness of our current fossil fuel situation, I'm seriously considering buying a diesel vehicle and converting it to run on biodiesel. From what I've read about it, it seems that the costs of a decent diesel vehicle to start with and the conversion is initially higher than buying a good beater that gets 30mpg on pump gas, but the fact that I would be able to run used cooking oil from the local greasy spoon is rather appealing.

I've seen people do it to old Cutlass Diesels, Mercedes 300 series Diesels (the 5 cylinder diesels from the late 70's-late 80's), diesel pickups from the 70's to brand new models, and a couple of other interesting vehicles. I have even found some complete vehicles that are already converted selling on eBay.

For those of you who don't know how a biodiesel conversion operates, here is a crash-course based on the internet research I've done. You start with a vehicle that has a diesel engine. It can be anything, from a '86 Ford Escort Cosworth to a full-size Turbo Diesel Dually Pickup, as long as it runs on Diesel fuel, it's a candidate. The first thing to do is boil or replace the fuel tank. This is to remove all of the crud and deposits from the tank. This should be done on any vehicle that isn't brand new. The next thing is to replace the fuel lines (any vehicle made before 1990 requires this, you can get by with stock fuel lines in anything newer than 1990). The older vehicles used rubber fuel lines, which can be destroyed by biodiesel fuel. The next component is going to be a tank heater. This is to make sure the fuel in the tank doesn't solidify. You can get tank heaters that kick on when the temp gets below a certain temp and automatically shut off when the fuel reaches the optimum temperature. Another item that will be needed is a fuel line heater, this is to heat the fuel again before it reaches the injectors. That is basically the gist of a single-tank conversion. There is another option, a dual-tank system, but it's a little more complicated. Basically, it runs like a hybrid vehicle does, when you start the vehicle, it runs on straight pump-diesel. Coolant from the engine is routed through a heating coil in the bio-fuel tank, and when the bio-fuel reaches the optimum temperature, a computer shuts down the diesel pump and starts pumping bio-diesel into the engine. When you shut off the engine, the computer purges the engine and fuel lines of bio-fuel and primes them with straight deisel again. There are additional measures that need to be taken with this kind of setup, as cross-contamination between the two tanks can cause engine issues. There are full conversion kits for this type of setup for many late-model Diesel Trucks, and they include a bed-mounted fuel tank and a filtration system in the tank, as well as all of the computer equipment and wiring you will need.

So, what are your thoughts? I didn't mean to ramble on about it, but I've been tossing this around for quite some time, and I'd really like to get into it, and I wanted to see what my fellow automotive enthusiasts thought as well.

93formulalt1
09-14-2008, 07:15 PM
Well, I've been looking for a candidate for the conversion, and I happened across an '86 Chevy Chevette 4 cylinder diesel/5 speed 2-door for $800. As soon as my truck sells, I'm all over it like a fat kid on a Twinkie. I'll post up a progress thread if and when the project starts. Those cars already get 45mpg running straight diesel. Might be worthwhile to just keep it stock!

krayzie7th
09-14-2008, 07:57 PM
^^keeps us posted.

Holset
09-14-2008, 09:39 PM
B10 is all they even sell around here. A biodiesel blend is a good thing to run now days due to the fact that all pumps offer anymore is ULSD (ultra low sulfur diesel). Sulfur is crucial to lubricity, and without it biodiesel is about the best substitute. Most vehicles will run a low blend without issue, but cummins did put out a TSB for their 5.9s (the ones they put in pickups) saying that they recommend an adittional fuel/water seperater for blends over B5. I run B10 everyday without issue, though.

edit: as for B100, I don't really have any input on that