Better gas mileage and performance.

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PlayingWithTBI

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L31MaxExpress touched on this in an earlier post when he mentioned BSFC (best specific fuel consumption). In layman's terms - bang for your buck. If the engine is closer to BSFC, for the same fuel burn as at a lower SFC, there's more power.
That's Brake Specific Fuel Consumption but, means pretty much the same thing.
 

Pinger

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That's Brake Specific Fuel Consumption but, means pretty much the same thing.
Correct - my sloppy!
To illustrate what we've been talking about, the 'oyster map' (top left one) shows where the best(!) BSFC is.
At around 3000 rpm with torque output of 2.25 N.m and the BSFC is 300g/kW.hr. At the lesser output (1.0 N.m) and lower rpm (2000) which many might think is the better load/speed range to accelerate most efficiently the BSFC is 540g/kW.hr - almost twice the fuel consumed for the same output or, about half the output for the same fuel burn. The map is for a 2-stroke but the point remains - engines have regions in their operating range in which they deliver more efficiently. Tapping into them pays dividends.

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edited to correct an error.
 
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L31MaxExpress

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To be pedantic, it takes the same energy.
Power is energy divided by time so to accelerate at a faster rate does require more power - but developed more efficiently and for a shorter time period - which the rest of your post elaborates on.
I actually meant energy. You have to use a certain amount of energy to accelerate a given mass to a given speed.
 

L31MaxExpress

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No, it doesn't. That's why drag racers build engines with as much power as possible.
I am not talking about drag racing here. I am talking about accelerating briskly near peak torque which is the absolute lowest BSFC an engine will experience and thus turning fuel most efficiently into acceleration.
 

0xDEADBEEF

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I am not talking about drag racing here. I am talking about accelerating briskly near peak torque which is the absolute lowest BSFC an engine will experience and thus turning fuel most efficiently into acceleration.

Regardless, if you get to the same speed in less time, it takes more power.
 

L31MaxExpress

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Regardless, if you get to the same speed in less time, it takes more power.
Yes it does, not debating that aspect. But it requires more power for a shorter duration. The total energy required to accelerate a given weight to a given speed remains the same. Thus you want to accelerate where the engine has its lowest brake specific fuel consumption.
 
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L31MaxExpress

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Here is an example I quickly found on an early 2000s Toyota 1ZZ-FE 1.8L. If I owned that model I would be accelerating with the shifts holding the engine as closely as possible between 2,500 and 4,000 rpm with as much throttle as I could but avoiding WOT fuel enrichment.

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Reluctanse

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Here is an example I quickly found on an early 2000s Toyota 1ZZ-FE 1.8L. If I owned that model I would be accelerating with the shifts holding the engine as closely as possible between 2,500 and 4,000 rpm with as much throttle as I could but avoiding WOT fuel enrichment.

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I daily a 1zz-FE with a manual, gonna give that exact strat a go!
 
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