Cylinder deactivation discussion

[RH77]

So, Chevy makes a V-8, front-drive Impala (which I will admit is fast).

People want a HEMI Charger, but they don't want to pay for more fuel.

The answer?

Cylinder Deactivation. LOTS of cake, and eating it until you're sick. Good idea. Poor implementation.

I've driven each of these applications, hooked up the SG, and found minimal advantages: 5% at best. The base engine in both examples have plenty of power and achieve much better FE. The Impala 3.5L pushes 30 mpg with mostly highway driving.

There has to be a paradigm shift in engine size perception. A 4-banger with a turbo is a good solution, but much of America still sees V-8 as "I've made it". That's where the manufacturers are. I wish I could have manually cut the cylinders -- it would have helped in-town driving for sure, but how much? Dunno.

I wish the best to those testing this experiment -- just make sure to perform ample research.

RH77

[diesel_john]

would two smaller engines, in essentially one box, connected by a clutch, so one or both could run work better? almost half the engine fictional and pumping losses. both could be kept warm by one, ready if needed at the next mountain.

[Frank Lee]

Good, good, good, good vibrations! (P.S. I really mean bad vibes)

-If you've ever had to synchronize multi-engined equipment, you know what I mean.

[RH77]

Does anyone remember the "Push-Pull" Chevy Citation X11 with 2 engines: front and rear ('85 I think)?

This is an interesting idea -- as AWD hybrids are generally driven at the rear wheels by electric motors along with the CVT/Gas-Engine up front.

I wonder how 2 small engines would fair in a real-world application... A small diesel on both ends: both work for acceleration from a standing start and one for cruise. Brainstorming over here...

RH77

[Frank Lee]

I have considered such a beast before and decided that the engine(s) either need to be split from within a common block, or be close enough together to share coolant and oil so as to keep the "part-time" stuff hot for when it's called to action. Letting the part-time stuff go cold all the time would be bad.

Then there is the vibes problem, they really need to be indexed to each other somehow or very disagreeable vibes will result... I think.

[DAN]

do not grind off the cam. set the valves. i once fad a shop grind down the fact shims. waste of money, the valves were shot

[DAN]

just about everyone has Cylinder Deactivation. it works. long ago ford said they were working on one that only shut off fuel to 3 of 6 Cylinders i've been tring to find info on it. i think (maybe) you could ground out some of the injecters and Deactivate that way.

[diesel_john]

i have extra cams. #2 chamber has a coolant leak any way. so i'll just weld or epoxy that. i going to use 1 & 4 so even fire, and a nasty rocking couple.

[Frank Lee]

John: I've disabled 1 & 4, and 2 & 3, and there was no noticeable difference in "rocking couple" vibes.

[brucepick]

Originally Posted by RH77

Does anyone remember the "Push-Pull" Chevy Citation X11 with 2 engines: front and rear ('85 I think)?... RH77

A related story. Not an FE project, I'm sure - but two engines, front and rear.

Pop Mechanics or Car and Driver or one of those... built a two engine car based on a fwd, 4-cyl compact. Probably n the '80's. I thought it was a Honda or maybe an Escort. Anyway, they added a duplicate engine in the rear, complete with stock fwd drivetrain. I think it had to be an automatic, since coordinating two linkages + clutches would be a project in itself. As I recall they had to move the gas tank and also did some suspension work so it would handle decently. Apparently it went like a bat out of heck.

No link between the two engines/drivetrains other than a throttle cable. And the tire/road interface.