Tandem Tadpole Car

[BLSTIC]

Given that we can't buy these yet FuelVapor Technologies - fuel efficient vehicle automobile high mileage I was thinking about building a similar thing.

Although perhaps with a 2.2 Prelude motor in it instead, but the concept is the same.

Has anyone done this before?

[jamesqf]

Originally Posted by BLSTIC

Has anyone done this before?

See the XR3 thread in the "Hybrids" section for something similar: http://ecomodder.com/forum/showthrea...one-12251.html

[Daox]

The Prelude engine would be huge for a tadpole car. Think more like a 250-500cc motorcycle engine.

[AJI]

Agreed, the absolute most you'd want is about a one-litre unit, and depending on the weight of the car, something smaller would be enough. I reckon any of the engines from the Smart range, whether it's one of the 1.0 naturally aspirated ones or one of the older 6-700cc versions, would be just right for such a car. Actually, Smart's 3-cyl turbodiesel would be excellent in such an application too.

[BLSTIC]

Ahh but I'm also interested in the needlessly fast. Simply getting rid of the surface area, drag, and mass associated with a 4-wheel car would be enough of an economy boost for me.

If it was to be a commuter car, I would probably choose a 660cc Kei class car as a base. With a respectable 47kw and peak torque around 3-4000rpm (redline around 8000) it would be a driveable, economic unit.

But seeing as I want to go needlessly fast too. Maybe a 1.3-1.5 turbo motor would be a good mix of both (say a Yaris RS turbo).

Also, for simplicity I would use the ENTIRE front end of the car. This makes it heavier though, but all the components are guaranteed to fit, over-rated for their new use, and anything you bend is easily sourced at a junkyard (if you bend the back end, well, **** happens). It also means that the complicated end of the car is already built.

[jamesqf]

That's my fallback plan for when some idiot rear-ends the Insight :-)

[zoltanbod]

Originally Posted by BLSTIC

Given that we can't buy these yet FuelVapor Technologies - fuel efficient vehicle automobile high mileage I was thinking about building a similar thing.

Although perhaps with a 2.2 Prelude motor in it instead, but the concept is the same.

Has anyone done this before?

Hello, from Canada.I have been working on my concept tadpole front wheel drive turbocharged 3cyl 3 wheeled car now for just over 2 years.You can look at my album here or check out my videos on Youtube.It is called the Zoleco.Some details about the car have been discussed in previous posts.

[The Toecutter]

I'd recommend looking to motorcycle engines then, if you want needlessly fast. Some of them on the market, stock, are showing impressive figures of over 150 HP per liter of displacement. Modified, the numbers can get into the 400+ HP per liter range...

Top speeds of over 270 mph, engine outputs of over 700 horsepower, and performances in the standing quarter mile as quick as 7.125 seconds and as fast as 209.14 mph have been recorded by street registered Hayabusa motorcycles using standard-width (190mm) DOT-approved street-legal rear tires.

http://en.wikipedia.org/wiki/Suzuki_Hayabusa

*drool*

[BLSTIC]

No, no motorcycle engines for me. 150hp per litre might sound good, but they do that at sky high revs, have wild camshafts, and get worse highway economy then a lot of cars. A 6spd sequential box would be cool though

Some of you also seem to be missing the point that if I start with a FWD car there are an awful lot of things that are already done for me. Front suspension, brakes, all the wiring except the rear lights (which can be salvaged bike units hooked up to stock wiring), a road legal lighting system, the basis of the front end body work, the cooling system, it's all there.

If I start with a bike, I need to make all of that from scratch, along with modify the bikes rear end to cope with the much increased side loads. The only advantage I end up with is a tachometer that goes to 12,000rpm, a 6 speed sequential box (which I need to somehow get reverse out of), awesome noise, and probably an overall lighter vehicle. RWD does not concern me in a 3 wheeler, and is potentially far more dangerous in a low grip situation.

I am prepared to sacrifice 200kg and a dozen or so MPG to not have to make a lot of that stuff. And car engines are generally capable of a lot more power if I do end up wanting more speed. To get 500hp out of a B18C/H22A/SR20/4A-GE is a known thing. Trying to screw that much out of a bike (and it's specific and not very interchangeable gearbox) would be quite the engineering feat.

Economy is important, but so is ease of construction, and I'm thinking of making something that has more than one purpose. An economical commuter that can lay waste to everything at a track day. Normally those two goals would be at odds with eachother, but a race car without downforce and a single person commuter don't have to be that different.

[The Toecutter]

I know you discounted the use of motorcycle engines, but it is not impossible to rig them up for FWD; there are also small diesel engines used for motorcycles that have impressive efficiency numbers, if you don't wish to go with an inefficient 12,000+ rpm engine(Although if you did, given motorcycles using them can get 35+ mpg hwy, it is not unreasonable for a car with half the drag to get double that, although you may want more mpgs than that. You did mention performance... lol).

I like the idea of using the diesel engine from the smart ForTwo. With a few modifications, getting 120 hp out of one shouldn't be too expensive, and for a streamliner with a frontal area of 9 sq ft or less, insane top speeds would still be possible. A few hundred pounds of weight won't make a huge difference in highway fuel economy, although it will make a substantial difference with regard to acceleration and city fuel economy.