has anyone tryed to run motors on less cylinders on the highway
 

i was wondering if anyone has experimented with running say a 4 cylinder car on 2 cylinders on the highway? i know cadillac did those 8 cylinders but they were big loads.

i started thinking of this when i was on englands toyota website and saw that they offer a yaris with a 1.0 liter gas motor that gets somewhere in the 60's mpg.



what i was thinking of doing is installing a toggle switches mounted on the dashboard so i could turn off 2 of the fuel injectors on my 2.4 liter motor when i was on the highway at cruising speed so it would be a 1.2. liter. i know that the motor would have the drag from the 2 non functioning cylinder and would be fighting the compression of them. so i was thinking of installing something to hold the exaust valves open when the injectors were cut off. kind of the opposite of a jake brake on a diesel truck.


i did try unpluging 2 of my injectors and driving the car around town and it did run but was really slugish but it was fighting the compression stroke on the 2 cylinders.

has anyone tried something like this? any info would help.

Others on this site have tried it. I don't think anyone has managed to succeed. It requires a lot of R&D and investment in engineering to do correctly. You need to close all the valves on the deactivated cylinders to turn them into air springs that return any energy put into them.

GM offers it on many of their V8 vehicles right now (they call it Active Fuel Management or AFM), and I think other major manufacturers have it too.

all attempts I've read on here were dismal failures. they've tried cutting fuel, spark, disconnecting rocker arms, etc etc. the engine's just not meant to run on half it's cylinders. GM offers it on the new 3.9 v6 too as well as dodge and ford on many of the V6 and 8 engines. The imports get better mileage without killing half the engine at a time :-p. part of why it works for them is that the deactivated cylinders alternate which cylinders are active and space them so the overall cycle is still even. I'm guessing GMs system grew out of the overheating limp mode that cut fuel to a few cylinders at a time (again, alternating) over 250f in some models starting in the early 2000s

AFAIK the imports and the domestics have virtually the same deactivation systems.

If they do I've never seen it advertised. It's certainly possible.

Most domestics with cylinder deactivation are pushrod engines that just collapse the lifter and I think imports use their cam switching system to accomplish it.

Yes, I believe it all started with the old Cadillac Northstar V-8.

The V8-6-4 was no Northstar.

Google is freely available to all...

https://en.wikipedia.org/wiki/Cylinder_deactivation

https://en.wikipedia.org/wiki/Variabl...der_Management

all i know was when my 4 banger truck's coil pack would get morning dew dripped on it it would wipe out 2 of the cilynders (one coil pack controls 2 plugs)

funny it only did it when you were eavy on the throttle (pulling out into a 4 lane highway) it would idle fine but it would not accelerate at all on 2 cyl.