Blending biodiesel and E85 for nondiesel engines

[Dr. Jerryrigger]

So there may be some major holes in this idea, but I was thinking about this recently. There is a gas station near me that sells E85 and I have some old deep frier oil. I think I'll try it out in my chainsaw first.

The BTU's per gal of biodiesel are slightly higher than that of gasoline, and the opposite is true of E85. The over all blend would work out to be a bit lower than gasoline, but not by much.

E85 has an octane rating of about 105 and biodiesel is at 45-60, so a 60-40% blend would make something my car could theoretically run on.

Any thoughts? I have been unable to pull up anything from google on this subject.

[theholycow]

So are you going to brew your "old deep frier oil" into biodiesel to mix with the E85?

Whether you'll be mixing in biodiesel or unprocessed waste oil, if you're using any significant amount of it I suspect it won't work well. If you're trying it in your chainsaw first then there's less to lose, I guess, as that carburetor should be easy to remove and clean, and the chainsaw is probably much more sensitive than the car.

[Dr. Jerryrigger]

Originally Posted by theholycow

So are you going to brew your "old deep frier oil" into biodiesel to mix with the E85?

Whether you'll be mixing in biodiesel or unprocessed waste oil, if you're using any significant amount of it I suspect it won't work well. If you're trying it in your chainsaw first then there's less to lose, I guess, as that carburetor should be easy to remove and clean, and the chainsaw is probably much more sensitive than the car.

Why do you think it wont work well? I mean, I also have my doubts, but I'm curious if you see any specific problems. And why do you think the chainsaw would be more sensitive? Maybe that was sarcastic?

[theholycow]

I don't think it will work well because there is more to fuel compatibility than BTU content and octane rating.

On further thought I was probably wrong about the chainsaw. Chainsaws, being two stroke, might run pretty decently on that mix. I forgot about that issue and was thinking in a 4-stroke frame of mind. Small engines, in my experience, are much more sensitive to fuel quality than modern car engines. Small engines mostly have simple gravity-fed carburetors, no sensors or feedback systems, etc. They barely manage to run on the fuel they were designed for. Cars have high-pressure computer controlled systems that use sensors to figure out what's going on and compensate. I can put stale gasoline in my truck and it runs fine...put it in my mower and it doesn't run at all.

[Dr. Jerryrigger]

Okay that make scenes. I have an old 4 stroke lawnmower motor kicking around I should also try it on before the car. I should also make sure my gas tank has a drain plug...

[theholycow]

Your car's tank won't have a drain plug, but if you decide to try it you should try low concentrations first...start with some regular gas in the tank and put a small amount of your mix in, if it runs ok (don't forget it might take up to half a gallon of consumption before the new mixture reaches the engine) try a little more of your mix, etc. Don't let the tank get full until you know it'll run on mostly your mix. If it starts running badly try topping off with regular gas to dilute it back to a usable level.

You want to avoid having to remove the contents of the tank. I've been there done that. It was a HUGE pain.

[Dr. Jerryrigger]

Originally Posted by theholycow

You want to avoid having to remove the contents of the tank. I've been there done that. It was a HUGE pain.

Next time that come up; disconnect a fuel line under the hood and put the hose in a gas can. Turn the car to "on" and the fuel pump will do the work for you.

Some cars do have a gas tank drain plug, very few, but some.

[Jay2TheRescue]

I would be concerned in pushing a mixture containing that much oil in it through a modern automobile engine. You could foul the plugs, O2 sensor, and cat converter. This experiment could end up with some costly repairs. The chainsaw on the other hand, is designed to burn a mixture of fuel and oil, and may actually run well with some carb adjustments.

[Dr. Jerryrigger]

Originally Posted by Jay2TheRescue

I would be concerned in pushing a mixture containing that much oil in it through a modern automobile engine. You could foul the plugs, O2 sensor, and cat converter. This experiment could end up with some costly repairs. The chainsaw on the other hand, is designed to burn a mixture of fuel and oil, and may actually run well with some carb adjustments.

Yeah Jay, you summed up the primary concerns I had pretty well. Don't mind fouled plugs so much as the others... $$$.
In a bio diesel I've heard of no problems of cat's dieing faster, but they don't last all that long on a diesel normally.
I'm also worried that the oil will not mix well and the ethanol will rise to the top. But that experiment can be done in a mason jar with my car unharmed.

[theholycow]

Originally Posted by Dr. Jerryrigger

Next time that come up; disconnect a fuel line under the hood and put the hose in a gas can. Turn the car to "on" and the fuel pump will do the work for you.

Some cars do have a gas tank drain plug, very few, but some.

Yup, I did that, but I realized the pump couldn't access all of the liquid and I had to get into the tank anyway. Gas was $4/gallon and I didn't want to risk another $100 finding out that I needed to get those last few gallons and wipe it clean.

Also, it's not enough to turn the car to "on", you have to turn on the fuel pump yourself; it doesn't run continuously with the key "on" and the engine off.