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Old 01-22-2016, 04:49 AM   #87 (permalink)
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Originally Posted by ConnClark View Post
The biggest argument against fast acceleration is that excess pressure is left in the cylinder when you lay into the gas and it just ends up as noise when the exhaust valve opens. Its called blow down and with the otto cycle it is un avoidable. The more gas you give the engine the more that goes to waste.
I think the biggest argument against fast acceleration, is mainly high RPM.
When having a CVT, best results come from running the engine at the lowest RPM needed for the load; eg: low acceleration, keep RPM at 1500RPM.
Fast acceleration, at 1500RPM it might be lugging; so RPMs go up to where the engine has enough torque to pull it off.

Ever heard of advancing the timing of an engine?

In a way, it's doing exactly the same thing as increasing the load (or increasing the gearing).
It's running the engine in a much more efficient state.
Too much, and the engine will lug, ping, or shut down.
Too little load, and the engine will run inefficiently.
Most cars are tuned to run fine when towing it's own weight up a 25 degrees hill in 5th or 6th gear. That makes for good acceleration, but also lower MPG.
Reducing that buffer, may make the engine much more fuel efficient, but also less able to tow heavy loads uphill.
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