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  1. #33
    Fuel Injected!
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    Quote Originally Posted by steveo View Post
    what works for one engine won’t necessarily work for another. comparing this airplane engine to an lt1 highlights the total absurdity of your generalizations both here and elsewhere. combustion chambers flame fronts and air fuel charge dynamics are an insanely complex thing with so many inputs and outputs and that’s why tuning is required in the first place. lots of engines melt down when lean, and lots can run 25:1+. lots of factors involved.
    A V8 engine is not going to melt down making the 40-50 hp it takes to cruise. Even at 80-100 hp its not going to melt down. I don't care if you were to run it lean enough to cause misfire. You will melt the cats from misfiring before you hurt the valves or pistons. The only way you will melt it down is to run it lean at high rpm and high throttle. You are actually more likely to destroy it at long periods of stoichiometric air/fuel at WOT as the combustion temps are hottest.

    Its actually not absurd at all. It was also a proof of concept not execution. The principle does work and I have applied it to Chevy V8s. Keep in mind that engine was running at a lower rpm than most of our vehicles and also running at about 30 in/hg manifold pressure. That is WOT for a non supercharged car at sea level.

    Also having a couple of EGT probes and a gauge that monitors both has taught me a thing or two. Under sustained WOT with an air/fuel ratio of around 12.5:1 my EGTs will rise to about 1,350°F. In stoich cruise at 70 mph the EGTs run around 850. In lean cruise they drop to 775. The excess air is cooling the combustion process. The oil temps also drop. With both EGT and Oil Temps lower that means the pistons are running cooler and so are the valves.
    Last edited by Fast355; 12-03-2019 at 08:42 AM.

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