Engine Computer Remap for better MPG

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03-06-2012 | 07:54 AM

#31

Noodler

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Joined: May 2009

Posts: 742

Likes: 1

From: NorCal

You cannot have fuel inj drive during decel. Throttle at ~0% with >idle rpm, commands no fuel inj drive.

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03-06-2012 | 10:11 AM

#32

LeonV

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Joined: Jan 2012

Posts: 690

Likes: 12

From: SF Bay Area

Quote:

Originally Posted by g0g3tt4

Take your car out of gear while braking. Cars use more gas during deceleration than W.O.T. (High Vacuum, low amount of work being done).

Quote:

Originally Posted by g0g3tt4

I guess I should have gone further in the explanation.

Depends on application. Many of todays cars don't suffer from deceleration fuel consumption. Older non-fuel injected engines did and still do suffer from it.
Cars that were vacuum controlled versus CPU controlled today.
Although we are still trying to control deceleration use of gasoline without encountering the on/off hesitation that accompanies that control, and further the peak efficiency of the engine.

Your statement makes no sense, irrespective of fuel delivery method.

A carbureted engine will use more fuel on decel than an EFI engine, but in no way in this world will it use more fuel on decel than WOT!

EDIT: The lesson of all this is to stay in gear when slowing down! Plan ahead, so you can coast to a stop instead of slamming on the brakes. I stay in gear as long as practical and use the brakes as little as possible to maximize the energy that I've burned in the cylinder per distance traveled. Brakes just eat energy away by dissipating irrecoverable heat. Keeping the car in gear helps "recover" some of that lost potential energy used up in accelerating.

Of course, track or autoX driving does not fall along these lines!

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