Lightweight Fusion

[cRiPpLe_rOoStEr]

Originally Posted by Old Tele man

Maybe, but welding does not ADD weight to what already exists; applied adhesives however DO gradually ADD-up, increasing weight...albeit not much.

Welding does add a little weight too, due to that alloy used to join the metal pieces.

[oldtamiyaphile]

Originally Posted by cRiPpLe_rOoStEr

Welding does add a little weight too, due to that alloy used to join the metal pieces.

Cars are almost entirely spot welded, no material is added at all. I can't think of many places I've seen seam welding on a modern unibody car.

[cRiPpLe_rOoStEr]

Originally Posted by oldtamiyaphile

Cars are almost entirely spot welded, no material is added at all. I can't think of many places I've seen seam welding on a modern unibody car.

You probably never seen a Brazilian modern car

[oldtamiyaphile]

Originally Posted by kir_kenix

Imagine what a Fiesta or Chevy Spark would end up weighing...a very light and inexpensive .5L turbo would be adequate and return amazing MPG.

I have a 900kg (OK not super light for it's size but lighter than Fiesta/Spark etc), 2 cyl 875cc turbo that gets terrible economy, ~45MPG US. It's also impossible to beat the EPA figures with. Of course, the small turbo twin is more expensive than the standard 'four'.

There seems to be a limit to how small you can go.

[cRiPpLe_rOoStEr]

Just downsizing the engine is not a miraculous solution regarding fuel-savings, we may also consider the tuning set at the downsized engine...

[kir_kenix]

I agree that downsizing the engine does not automatically increase the fuel economy. The new engine and transmission would have to be set up to return better economy as well. It does however take less materials to build a smaller engine, which lowers the weight further. Reducing the weight also means that it takes less HP to get that vehicle moving, and less HP (assuming aerodynamics are the same) to keep that vehicle cruising on the highway.

If set up correctly, a lighter vehicle with an adequate engine will return better fuel economy than a heavier vehicle requiring a bigger/more powerful/heavier engine that performs as well on the road.

[cRiPpLe_rOoStEr]

Originally Posted by kir_kenix

It does however take less materials to build a smaller engine, which lowers the weight further. Reducing the weight also means that it takes less HP to get that vehicle moving, and less HP (assuming aerodynamics are the same) to keep that vehicle cruising on the highway.

That's one of the reasons why I'm even favorable to the 2-stroke engines

[kir_kenix]

I don't have any experience with 2 stroke automobiles, but I've ridden my fair share of 2 stroke motorcycles and 4 wheelers. My only complaint with the 2 strokes I've ridden is the complete lack of low end grunt they possessed. Maybe its only the examples I've been on, but they made crazy power really high in the RPM range vs conventional 4 strokers.

I rode a 500cc Kawasaki that had been made street legal (thank you SD for your ridiculously lax licencing requirements) from Sioux City to Michigan once. It was probably the worst ride of my entire life, but it was filled with plenty of smiles when I got on it.

If they could be made emission complaint and paired to the right transmission, a very light 2 stroke automobile would be alot of fun while remaining economical.

[cRiPpLe_rOoStEr]

Nowadays that direct injection is getting widespread in marine 2-stroke engines, both the emissions issue and low-end throttle response are getting addressed. Regarding higher RPM, they also have an advantage because they'll never have valve floating like some 4-stroke engines...

[gone-ot]

Whatever happened to that PLASTIC engine that was developed years ago ?