Effects of killing one injector - 4 cylinders

[IsaacCarlson]

Just disabling cylinders might get you 10-15% depending on the application and how it's driven. To get the most out of it, you would have to eliminate the drag of the dead cylinders by removing rods, pistons, valve trail components. Ford had a 300-6 that would disable half of the valves to make a 3 and it had some increased mpg, but nothing crazy because the pistons were still in there.

The 300-6 will run smoothly with the front/rear 3 cylinders only

[Kzelisko]

Cylinder deactivation is a proven technology that exists even on 4 cylinders, but the gains are only in the 10-15% area from what I've heard. If we started rotating cylinders that are shut down, the balance of the engine would suffer and likely so would the economy gain.

[Angel And The Wolf]

Originally Posted by Kzelisko

If we started rotating cylinders that are shut down, the balance of the engine would suffer and likely so would the economy gain.

I don't see that, over just the one cylinder every two rotations. Can you explain the difference to me, or point me to documentation?

The 10-15% I can see, as the car still weighs the same.

[Kzelisko]

Engines are balanced by cylinder firings being even, if you have one cylinder shut down that, especially if it's not always the same one, then the firings won't be even causing significant vibration. There are engines that have unbalanced firing orders like odd-fire v6's and three cylinders to name a few, but those typically have flywheels, harmonic balancers, balance shafts and other means to tune out the vibration. If the source of the unbalance is a moving target, there really isn't any realistic way to counter it.

[Shaneajanderson]

The mechanics of varying which cylinder is shutdown could be complicated... but otherwise I think it would be fine. I've driven a V6 with two dead cylinders, and though it shook like crazy at idle and under heavy load, cruising was fine, you'd have never known it had the issue other than the CEL.

[Fat Charlie]

I disconnect all 4 cylinders all the time using P&G, and deactivate all 4 of them regularly with EOC. Not a lot of wrenching or theory, just driving.

[Tahoe_Hybrid]

2960 miles with Active fuel management (these are known to burn upto 2qt per 1000 miles)

Zero oil consumption on this Wednesday engine

I do 3000-3500 oil changes I have an appointment to take it in on Monday for an oil change.. that will be 3150 miles or so