[Shop-talk] 6 to 3 fuel saving

[Eric Murray]

On Mon, Jul 28, 2008 at 08:08:15PM -0500, Elton E. (Tony) Clark wrote:
> *Okay, open your minds . . . the guy on the next bar stool opines that on
> his straight six '95 Jeep Cherokee work car,  he is considering removing the
> rocker arms and pushrods on every other cylinder in the firing order and
> running it on three cylinders to save gas..  The closed cylinders would
> resist rotation on compression but rebound on downstroke with little loss
> except friction.  *
> **
> *I'm  thinking this would probably work for some saving but at a steady
> state throttle opening, won't it just require about the same fuel to achieve
> equilibrium with the wind resistance and rolling resistance? 

Yes.

If it's driven at the same speed, the only savings will be the lack
of valve train friction in 3 cylinders.

That's not zero, but it's not very much.

Switching to highway tread tires would do more.  As would
keeping the tires a bit over inflated.  Or using the Cheroke to
haul a bicycle to within commute distance to work and riding in.

Of course halving the power would encurage a more sedate driving style
which itself would result in increased mileage. But he could do that
without touching the engine just by driving slower.


Eric