idea, 4 cylinder to 2 cylinder engine conversion

[Frank Lee]

You mean Rest In Pieces.

Any EMers with a DoD vehicle have real-world DoD fe increase data?

[ShadeTreeMech]

Originally Posted by EdKiefer

I don't follow why you think O2 would dump more fuel in as long as no air is being drawn in. O2 don't know or care if its 2 ,4 ,6 or 8 cylinder, its the % that it reads not quantity . now if intake valve was open it be different story, it would "try" and compensate to keep 14.7

What i'm referring to is a vehicle running on half its cylinders due to injectors being disabled. If there is no gas going in and no fuel being burned then all that atmospere being pulled into the "dead" cylinders will be dumped out the exhaust. This will cause a high 02 content.

Sure, if the intake valve could be made to stay closed it would solve the problem, but that would be a bit complicated I believe.

[ShadeTreeMech]

From Multi-Displacement System - Wikiautos

Multi-Displacement System
Chrysler's Multi-Displacement System (MDS) is a variable displacement technology which is capable of deactivating four of a V8's cylinders under certain driving conditions, such as when the throttle is fully closed or when the vehicle is cruising at highway speed. The system is used on Chrysler's 5.7-Liter HEMI(R) V8 engine and is available on all Chrysler, Dodge, and Jeep models which utilize this powerplant. These models include the Chrysler 300C, Dodge Charger, Dodge Magnum, Jeep Grand Cherokee, Dodge Durango, Dodge Ram, Jeep Commander, and the Chrysler Aspen sport utility vehicle.
The purpose of MDS is to increase fuel economy. Chrysler states that its MDS technology can increase fuel economy by up to 20 percent. For example, the 2008 Chrysler Aspen is rated at 13-mpg city and 17-mpg highway with the standard 4.7-Liter V8, which does not feature MDS. Upgrading to the larger and more powerful HEMI engine with MDS brings mileage estimates up to 14-mpg city and 20-mpg highway. This provides buyers with improved fuel economy, more power, more acceleration, and increased towing capacity.
The operation of the MDS system is automatic and seamless.

I suspect the reason a 4 cylinder with the valves left closed on 2 cylinders won't run is because the air inside is trapped and acts to destabilize the engine due to 2 shock absorbers effectively being strapped to the crank. The air flowing through would likely cost less energy than it just sitting in there causing issues with the ECU not getting the amount of airflow it expects.

[ASV]

how about building another lobe onto the intake and exhaust cams
plugging the spark and injecter ports
diverting the exhaust of the converted cylinders to the intake of the others
and grinding out the remaining two combustion chambers to drop compression back down a bit


all cylinders intact and doing work
much higher compression


or flip that idea on its head divert exhaust to the converted cyliners
inject some hot watter and you have a duble expantion on the same heat

[bestclimb]

Originally Posted by ASV

how about building another lobe onto the intake and exhaust cams
plugging the spark and injecter ports
diverting the exhaust of the converted cylinders to the intake of the others
and grinding out the remaining two combustion chambers to drop compression back down a bit

Or drill a couple holes in the top of the deactivated pistons to reduce the pumping losses. or has that been tried :wink:?

[ASV]

why dount you read the post again I think you are missing somthing
all that would get you is a lot of drag and even more noise
I am talking about adding boost

or adding 50% more power sroke per rev on half the displasment

[bestclimb]

i got you now, i was thinking compression in leak down terms, I was thinking you were talking about letting gasses escape down the cylinder walls to reduce compression in the deactivated cylinders.

[Phantom]

Originally Posted by Frank Lee

Re: yet another test with pumping air and the O2 sensor: I wonder if simply unplugging the O2 would keep it in open loop; at least then the ECU would be running off the map and not try to correct the "lean" condition...

Speaking only from my experience on tuning 3800s in SD mode we can keep the ECU in open loop by removing the plug for the MAF sensor. That prevents the car from going to closed loop but allows you to see the O2 values.

I do believe that disconnecting the O2 should do the same thing but allow you to read the MAF sensor in open loop.

[saand]

Phantom, this is actually already on my "to do" list ill be testing when my car is in open loop then ill disconnect the o2 sensor and see if i can force open loop. This was as a separate investigation to the 2 cylinder mod as id like to try out lean burn on my standard 4 cylinder. Either way if i can force open loop operation it might make cylinder deactivation easier. It may also make the car very unreliable maybe

[Accord_Guy]

Hey, I'm new to the forum but thought I could add a little something here.
I've got a 94 Accord (2.2l) that I've been running successfully on 2 cylinders for the past month or so. I have not modded the engine yet to remove the extra drag from the 2 'spare' pistons moving up and down nor have I removed the rockers from the valve train. The effect thus far is that the engine runs a little rough at low RPM but runs sufficiently smooth and with enough power to achieve and maintain highway speeds. The ECU in this model is dumb enough to not care that I am only running 2 cylinders and does NOT post any codes. I have simply disconnected 2 injectors and connected a load on the injector lead so that electrically the computer thinks that the injectors are still there. I used old injectors and they are simply dangling down the side of the engine.
My plan is to complete the mechanical mods which include removing the rockers and pistons (leaving cut-off con-rods on the crank) and re-timing the balance shafts as best as can be to help with low RPM wobble. Once all this done I will be getting an emissions Test and doing a consumption test run of 400-500Km. I am fairly confident that this will work but would like to take it another step... these engines are usually fairly smooth at low RPM because they have 2 balance shafts, it'd be great to find the right timing to re-balance the engine to allow it to idle well as well. Your thoughts?