If You Were Going To Build A 200mpg Car..

[trautotuning]

Originally Posted by DRW

Here's one that's not quite finished http://www.jalopnik.com/cars/alterna...own-335325.php
It's a DIY lightweight 3 wheeled diesel-electric hybrid. Even if you don't buy the plans for this one it'll still give you some ideas.

Something exactly like this is what I plan to build, exactly like it. (well more or less)

But I dont get one thing guys, I was looking at mpg of motorcycles and looked at;
-Ninja 500 50avg mpg
- Hayabusa 1300 50avg mpg

How can they be the same when one puts three times more power and weights more? (It is more aerodynamic, but is that all?) It got me to thinking why would I sacrifice power when I can get the same fuel economy...? Or am I wrong?

[dkjones96]

Wow, 50mpg for a Hayabusa? that's pretty good considering what I hear people saying they get.

When choosing an engine you should choose one that just meets your needs. We know an engine is most efficient when it's just under max torque demand at it's torque peak.

If I was going to build a MPG monster I'd use a Microsquirt system on a small 5hp engine with a very small turbo on it and a billet rod, forged crank and piston for when I need power. Fuel of choice for me would be propane.

I'd build a small direct injection system for it along with removing the magneto and running electronic ignition.

There is the problem of air cooling limiting you as far as power goes but if your needing power just richen it up. It's EFI you could do whatever you want. You could even make it where the engine is only really good for good power as long as it doesn't heat up to a point that heat in the engine starts to causes it to start knocking and your timing starts to retard a lot.

[GasSavers_Ryland]

about 9 years back I built a vehicle for the super mileage vehicle competition, it had a 3.5hp briggs and straton engine that was left 100% stock, the top designed speed was around 45mph because the competition had a track speed limit of 30mph, so that is the speed that it was tested at, no pulse and glide, no fancy driving of any sort other then maintaining a consistant speed of 30mph and in a single afternoon of the competition it reached 245mpg, of course I have photos and design drawings.

of course a vehicle like that would have to be lisenced as a moped or scooter, and I've thought about doing exactly that, getting a scooter frame with a title and building a vehicle like that around the rear end of the scooter, I think I would either stick with a 50cc honda scooter engine, a honda dirt bike with a 250cc water cooled single cylender engine, or a Vespa scooter with the 250cc fuel injected engine, and I think it's water cooled as well, the only draw back of the vespa engine is that it's hooked to a cvc belt tranny, very inefficent, but they do that for simplicity, it still gives the scooter a 80mph top speed, and is reasonably light weight.

[VetteOwner]

id try like a 5hp lawnmower engine with LOTS of gears. you can move a semi with a weed whacker engine if you have the proper gearing.

[GasSavers_Erik]

Ryland- wow, that was a great project- thanks for the pics and info

In the pics, it looks like the engine has a centrifugal clutch and then the honda clutch was also in there on an intermediate shaft. I am curious- why did you use two clutches?

[Big Dave]

If I were gonna build a 200 MPG car...

It has to have a roughly 10 HP diesel engine.
It is a narrowed four wheel car - three wheelers are wrecks waiting to happen
It uses tandem seating - one behind the other.
It has to have slicker aerodynamics than basjoos' Civic.
It has to be very, very light.

Every time I run this exercise, I come up with the overgrown sex toy that VW built. Yes, it looks obscene, but it gets 240+ MPG and keeps up on the Autobahn.

Could it be improved on? Yes. Lay the driver back even more. The optimum MPG shape for a land vehicle carrying a human being is a powered street luge with a fairing.

[usedgeo]

Ryland- You should have had Somender's grooves in that BS head. You might have done a bit better.

[VetteOwner]

Originally Posted by Big Dave

If I were gonna build a 200 MPG car...

It has to have a roughly 10 HP diesel engine.
It is a narrowed four wheel car - three wheelers are wrecks waiting to happen
It uses tandem seating - one behind the other.
It has to have slicker aerodynamics than basjoos' Civic.
It has to be very, very light.

Every time I run this exercise, I come up with the overgrown sex toy that VW built. Yes, it looks obscene, but it gets 240+ MPG and keeps up on the Autobahn.

Could it be improved on? Yes. Lay the driver back even more. The optimum MPG shape for a land vehicle carrying a human being is a powered street luge with a fairing.

so essentially a closed bobsled with wheels

[JanGeo]

Some numbers to think about . . .

200mpg converts to 0.005 gallons per mile about 0.02 L/Mile

My engine burning at idle 0.1 gph when it is warrmed up would have to be moving the car at 20 mph for it to be getting 200mpg. Usually I can only get about 60mpg at 20mph.

My electric scooter - powerful as it is, uses about 25wh per mile and to get the equilivalent gas mileage at 200mpg would be 45wh per mile. So my electric Scooter is getting about 360mpg. Based on 9kwh per gallon assuming 25% ICE efficiency.

Now you can understand why I don't think building electric cars it a good idea - better to build an electric motorcycle or trike.

[DRW]

How about a drop tank with wheels, a window to see out of, and a small diesel tractor engine?