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MetroMPG · 02-25-2009, 04:55 PM

Cruising at peak torque RPM for best fuel efficiency is a "rule of thumb" myth that gets regurgitated regularly. Not sure why.

Granted, different motors behave differently and there may be some where it may be true, but it's just not that cut & dried.

Graph a speed vs. MPG, or RPM vs MPG in top gear for your vehicle and I bet you a donut you'll find your best efficiency is far lower down the tach than peak torque (and also below the best BSFC zone).

02-25-2009, 04:55 PM	#13 (permalink)
MetroMPG Batman Junior Join Date: Nov 2007 Location: 1000 Islands, Ontario, Canada Posts: 22,527 Blackfly - '98 Geo Metro Team Metro Last 3: 70.09 mpg (US) MPGiata - '90 Mazda Miata 90 day: 54.46 mpg (US) Even Fancier Metro - '14 Mitsubishi Mirage top spec 90 day: 70.75 mpg (US) Appliance car Mirage - '14 Mitsubishi Mirage ES (base) 90 day: 62.14 mpg (US) Thanks: 4,078 Thanked 6,976 Times in 3,612 Posts	Cruising at peak torque RPM for best fuel efficiency is a "rule of thumb" myth that gets regurgitated regularly. Not sure why. Granted, different motors behave differently and there may be some where it may be true, but it's just not that cut & dried. Graph a speed vs. MPG, or RPM vs MPG in top gear for your vehicle and I bet you a donut you'll find your best efficiency is far lower down the tach than peak torque (and also below the best BSFC zone). __________________ Project MPGiata! Mods for getting 50+ MPG from a 1990 Miata Honda mods: Ecomodding my $800 Honda Fit 5-speed beater Mitsu mods: 70 MPG in my ecomodded, dirt cheap, 3-cylinder Mirage. Ecodriving test: Manual vs. automatic transmission MPG showdown EcoModder has launched a forum for the efficient new Mitsubishi Mirage www.MetroMPG.com - fuel efficiency info for Geo Metro owners www.ForkenSwift.com - electric car conversion on a beer budget