Uses for a small Kubota diesel?

[Gasoline Fumes]

I have a 4.5 HP Kubota diesel engine (EL300-AR). It was originally from one of those flashing highway arrows. What should I do with it? I saw it on craigslist earlier this year and couldn't say no. I was thinking bike or trike, but that might never happen. I could make a generator, but that's no fun to ride.

It's tempting to run it on WVO, but I'm not sure how tolerant it is of that stuff.

[Piwoslaw]

If it's not too big or heavy, maybe a range-extending generator for an EV or hybrid? Assuming you already have one, of course

[bestclimb]

aux power for a small sailboat?

[RobertSmalls]

Here's a half-baked idea for a 15HP diesel engine: you could do a gasoline/diesel hybrid. Have the engine drive a fifth wheel located beneath the cargo floor of your Civic wagon. Use the gas engine when you need to go 0-60 in less than a minute, and use the diesel for cruising. It's a poor man's cylinder deactivation / bi-fuel scheme.

However, 4.5HP will give NEV-like performance in any road car. 40mph, tops. 0-30, eventually.

In order to achieve highway speeds, you're going to need a streamlined, two- or three-wheeled vehicle, preferably under 500lbs.

[dcb]

It would be killer on my moped

[Gasoline Fumes]

Originally Posted by dcb

It would be killer on my moped

It's 2 feet long and weighs 100 lbs.

[Gasoline Fumes]

One of the reasons I might not build a trike is the difficulty of finding a suitable transmission. With a max RPM of 2000, it's going to need multiple gears to acheive a respectable cruising speed and still be able to accelerate. I have a 3-speed lawnmower gearbox that would be OK, but it's designed for a vertical shaft engine and is grease-lubed. My other concern is MPG. I'd hate to go through the trouble of building something and then find out it gets only 61 MPG and has a top speed of 34 MPH. It would have to get about 100 MPG and go 50 MPH for me to build it.

[Doofus McFancypants]

i would second the WVO generator setup for range extender.
At that RPM you are not going to get much direct drive applications without some customer parts.

[Frank Lee]

It would be the ultimate "cruise engine"- get up to cruise speed, activate Kubota, shut down regular engine, sip! (might need a sub-Metro sized vehicle to do that on though)

[Christ]

Originally Posted by Gasoline Fumes

One of the reasons I might not build a trike is the difficulty of finding a suitable transmission. With a max RPM of 2000, it's going to need multiple gears to acheive a respectable cruising speed and still be able to accelerate. I have a 3-speed lawnmower gearbox that would be OK, but it's designed for a vertical shaft engine and is grease-lubed. My other concern is MPG. I'd hate to go through the trouble of building something and then find out it gets only 61 MPG and has a top speed of 34 MPH. It would have to get about 100 MPG and go 50 MPH for me to build it.

Why such high expectations? What do you have that even comes close to rivaling that now?

Being more realistic, 61MPG on diesel which is basically free (if you make it yourself) is still a sight better than 100 MPG on $3.00 a gallon gasoline.

Average cost of BD when you make it at home, and using free WVO to make it, is about 90 cents a gallon, last I heard. At the price of the gas station next door, $2.70 a gallon for gasoline, I'd have to get 90MPG gasoline to match 30MPG diesel.

Your speed limitation isn't really all that realistic, either, I think. How many days do you really HAVE to go 50 MPH? Could you not suffice with 35-40 MPH?

Beyond that, there are many things you can do to increase the power output once you've built the project and gotten it working. Later on, you can streamline it, change gear ratios, increase output and efficiency with a small turbo, etc.

Build it, then worry about the details. Very few peopele actually stick to all of their goals when building something one-off. Compromise is necessary until the thing can be considered "tangible".