Honda's vtec-e eliminates 4 of the 8 intake valves on a 16 valve 4 cylinder, I don't see why you couldn't just grind off a few lobes to do this to any other engine. I mean, there would be obvious flow issues and such, *shrug* I'm not smart enough to say at this point.
I'm still worried that friction in the deactivated cyclinders would be too great to see fuel economy gain. Piston rings are the biggest source of drag in the engine. What about removing the piston rings in the deactivated cyclinders, but leaving in the rods and pistons?
Actually, this depends on the cylinders sealing well. It turns into an air spring, and with a modern design is pretty efficient. If there are no rings, it will continually force air past the piston, loosing a lot of energy.
I think the cam grinding idea is pretty good. The honda VTEC-e's do have a little lift on the non-working intake to prevent fuel pooling. I bet there are cam profiles that are more efficient even in a working cylinder. For example, the Prius has that special cycle where the exhaust is longer than the intake.
It is true that the 4 intake valves are not completely shut off, I didn't know that until about a month ago, but it makes complete sense. There are lots of people that do custom cam grinds for everything. It's just a matter of testing it out and see if it works, I guess.
Eureka! I've been interested m interested in building a two cylinder car. Converting an inline four isn't terribly practical because of balance problems. But a boxer engine would work super, since the cylinders fire evenly, and piston inertia tends to cancel.
I found a company that converts VW 4 cylinder engines into 2 cylinder engines for airplane/ultralight usage. I'll wager that if this engine was installed in an old Kharman Ghia, you could get 70-80 mpg.
I wonder if there is one on Ebay.
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