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Andyman · 03-25-2009, 04:15 PM

Judging by the BSFC charts I've seen, I think it is best to keep intake manifold vacuum at 5 to 10 inches of mercury and the engine speed in the 2000 to 3000 RPM range on most engines. If slower acceleration is required, then the shifting should be done earlier. Most cars will run smoothly if the transmission is shifted when the engine reaches 2000 RPM. After the shift the engine will probably be running about 1300 RPM. It depends on the transmission gear ratios.

I think it would be a good idea to avoid a heavy load when engine RPM is below 1500 because the oil pressure may be low and a heavy load could increase wear on the connecting rod bearings.

03-25-2009, 04:15 PM	#23 (permalink)
Andyman amateur mech. engineer Join Date: May 2008 Location: New York City Posts: 112 Sporty Accord - '88 Honda Accord LX-i 90 day: 23.25 mpg (US) Dad's Camry - '01 Toyota Camry CE 90 day: 22.81 mpg (US) Artie's Camry - '98 Toyota Camry 90 day: 37.3 mpg (US) Thanks: 0 Thanked 17 Times in 4 Posts	Judging by the BSFC charts I've seen, I think it is best to keep intake manifold vacuum at 5 to 10 inches of mercury and the engine speed in the 2000 to 3000 RPM range on most engines. If slower acceleration is required, then the shifting should be done earlier. Most cars will run smoothly if the transmission is shifted when the engine reaches 2000 RPM. After the shift the engine will probably be running about 1300 RPM. It depends on the transmission gear ratios. I think it would be a good idea to avoid a heavy load when engine RPM is below 1500 because the oil pressure may be low and a heavy load could increase wear on the connecting rod bearings.