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Old 03-02-2023, 06:16 AM   #19 (permalink)
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Originally Posted by Isaac Zachary View Post
The rotational mass or inertia is only part of the total inertial mass. So if you lower the rotational inertia by 10%, but rotational inetia is only, say, 20% of total inertia, then you only saved 1%.

The drive shaft also doesn't have a lot of inertia, even if it has a lot of mass. That's because 1. it usually spins slower than the engine, at least when starting out and 2. its mass has a small diameter, not a large one like the flywheel or the wheels.

I could be wrong, but I read somewhere that around 80% of the rotational inertia is in the flywheel. That's why you usually start there before reducing other things.

Aluminum also doesn't fatigue well.

But yes, every little thing adds up. However, there are things that may help only a fraction of a percent, and other things that would be better to put that money towards and get you more percents. Tuning each cylinder for fuel and spark would be one of those things.
Sure, and I'd like to know what that list is. You said aluminum flywheel. I have heard somewhere that they do "wear out" and need to be replaced eventually. But what about that harder aluminum? Maybe not cost effective in this case. All the racing guys seem to love aluminum driveshafts. So it would at least be good for a bit of power, if not actual fuel economy gains.

Back to this list of proven mileage increasers, maybe low rolling resistance tires should be considered. You'd just wait until your tires were worn out and had to be replaced anyway.

Is there a master list for typical internal combustion engines somewhere on this forum? Seems like there would be something like that by now.

I did find more efficient alternators:

Well I can't post a link.

Last edited by Solarpowered; 03-02-2023 at 06:22 AM..
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