Quote:
Originally Posted by wdb
Well well well. This is the first time in any fuel economy forum that I've seen an admission that engines have zones of efficiency. The mantra I've heard so far has been "low RPM in a high gear" and not much else.
I live at the top of a hill, and so I always have a long climb just before getting home; natually this plays havoc with my carefully collected trip MPGs. I've tried going really slow, using low RPMs, and the like, without seeing much difference. On the other hand if I keep my speed high enough to hold 3rd gear and 2500-3000 RPMs, the car seems happier, the MPG loss is a tad less, and as a bonus I get home a little sooner.
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Low rpm in high gear applies to cruising.
The idea is to accelerate to cruising speed by staying inside the lowest BSFC island while going through the gears. The load and RPM will vary by engine. Once you reach cruising speed (whether it be 40mph or 60mph), lowest rpm in highest gear while holding a steady vacuum is great. Pulse and Glide + EOC is the best, but some people may not like doing that.