[mechman600]

What a great website...so much info.
I have a 2001 Civic LX, non-VTEC, automatic (for the wife). It's my wife's car...my vehicle is a bicycle 1/2 the time, and a Yamaha scooter the other 1/2. I'm currently building a hydrogen generator for the Civic in my spare time just to see what happens.

I have a thought. Toyota's basic VVT-i system changes the timing of the intake camshaft. For low rpm it advances it, for high rpm it retards it. BMW's Vanos system (of the mid 90's to very recently, if not currently) changes the timing of both exhaust and intake cams and even uses this system to allow some in cylinder EGR action.

My question is: why not put an adjustable cam pulley on my engine and advance it incrementally until I get the best mileage possible. I've heard that this will work, but has anyone on this forum tried it?

Another thought: decreasing valve overlap/int&exh duration/lift with promote a power band much lower in the rpm range. On an engine with mechanical valve lash adjustment like mine, why not back the lash adjusters off to get the desired effect of a more economical camshaft? Like instead of my current 0.008"/0.010 lash (int/exh), try 0.015/0.017 or 0.020/0.022 or 0.025/0.027? You could even vary between pairs on a single cylinder to achieve a "dual cam pattern" effect. Yeah, I know my valve train would make a racket, but with some slick 50 (or whatever) and keeping the rpms down, maybe it would be tolerable.

The problem we (car users) have is that the engines have too much power. What I mean is that my Civic does NOT need 115HP to get the job done. 50 HP would probably do. So if i can change the engine to make it's peak volumetric efficiency at 2500 RPM instead of 5000 RPM, which in turn will lower my horsepower considerably, will not ridiculously better economy be a nice side effect?

One more idea: How about removing one intake and one exhaust rocker from each cylinder to make it an 8-valve engine instead of 16? It is possible, I checked it out when doing my valve lash adjustment. Or just the intake ones to make it a 12-valve? That would cause a major reduction in volumetric efficiency, and as a result, exponentially higher intake charge speeds. Besides, that's what a VTEC is doing at low rpm anyway.

I should stop thinking out loud now. I'm starting to scare even myself.

James