Guy here at work says his 2010 F150 5.4 drops to 6 then to 4 to save on fuel.

Is he smoking crack or ??

 

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Not unless you consider Fail safe mode a form of cylinder displacement. Dodge hemi is the only truck I am aware of that makes use of it.

 

That's what I was thinking.

He just bought it used over the weekend.
2010 F150 Lariat 4x4 with 48,000 for $27k

 

Dodge calls it MDS, Chevy/GM do it too. That's how they get their decent mpg numbers. The new stingray vette is going to be 30mpg highway because of this. IMO, it's cheating and the exhaust sounds like ***.

 

I wouldn't think the exhaust note would change much. The non-firing cylinders still inhale and exhale air at the same rate the firing cylinders do.

 

I can't comment on the exhaust note, but on my Impala SS with this feature, the shut down cylinders operate as air springs, with the valves stuck closed. That uses much less energy than inhaling and exhaling. That is, no air is passing thru the draggy valve openings. And whenever a sealed cylinder compresses the air during the up stroke, that energy is returned on the downstroke (minus some heat loss).

HTH.

Doug

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