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MPGeo · 09-03-2016, 11:22 PM

I have to agree with most of the comments already posted...

You would have to select the correct cylinders timing wise...
Eliminating the O2 is not beneficial...
Eliminating knock would do absolutely nothing since the remaining two cylinders would never knock under your proposed scenario...
Turbo lag would be ridiculous, and changing boost tables does nothing for you in this department...
Besides that, the reduced power output would still have to absorb the power requirements to move those two, now useless, pistons up and down for no reason.

But if you are like me, and won't take no for an answer until you try-it on your own, then I have a few suggestions before you cross the path of no return...

You don't want to grind the cam, simply remove your lifter/rocker mechanisms and you the lobes should not contact anything. You still should visually ensure that's the case, but I'm very confident that will be the case. That way you can re-assemble if need be without having to buy it/them again.

You really don't need or want to weld you valve ports shut. No need because your valve springs will make sure that those ports are properly closed unless your valves are not seating properly from wear or carbon build-up. But still you don't want to do this because if you maintain these passages closed the useless pistons would be fitting your other two working pistons in a perpetual compression stroke...

If I was to do this at all, I would remove the lifter/rocker mechanisms leaving the valves of the selected pistons closed, then I would remove the unused pistons... This would be the best option since it eliminates the parasitic losses created by those two useless pistons, and also allows you to not have to modify or even change either of the manifolds at all... at least not during initial testing phase.

But if removing the pistons is out of the questions then I would remove the valves for those unused pistons, and instead of welding anything shut I would leave both intake and exhaust ports fully open to the atmosphere. Simply because that would create the least amount of power loss, but this would require modified manifolds... Or I would remove only the exhaust valve so that I can still use my factory intake manifold without any modifications and only have to deal with the exhaust manifold... and this would do what you stated, pushing and pulling air out of the exhaust port.

Good Luck on your project!

09-03-2016, 11:22 PM	#7 (permalink)
MPGeo EcoModding Apprentice Join Date: Aug 2016 Location: Wilson, NC Posts: 132 MPGeo - '93 Geo Metro Base 90 day: 67.51 mpg (US) Thanks: 66 Thanked 56 Times in 36 Posts	I have to agree with most of the comments already posted... You would have to select the correct cylinders timing wise... Eliminating the O2 is not beneficial... Eliminating knock would do absolutely nothing since the remaining two cylinders would never knock under your proposed scenario... Turbo lag would be ridiculous, and changing boost tables does nothing for you in this department... Besides that, the reduced power output would still have to absorb the power requirements to move those two, now useless, pistons up and down for no reason. But if you are like me, and won't take no for an answer until you try-it on your own, then I have a few suggestions before you cross the path of no return... You don't want to grind the cam, simply remove your lifter/rocker mechanisms and you the lobes should not contact anything. You still should visually ensure that's the case, but I'm very confident that will be the case. That way you can re-assemble if need be without having to buy it/them again. You really don't need or want to weld you valve ports shut. No need because your valve springs will make sure that those ports are properly closed unless your valves are not seating properly from wear or carbon build-up. But still you don't want to do this because if you maintain these passages closed the useless pistons would be fitting your other two working pistons in a perpetual compression stroke... If I was to do this at all, I would remove the lifter/rocker mechanisms leaving the valves of the selected pistons closed, then I would remove the unused pistons... This would be the best option since it eliminates the parasitic losses created by those two useless pistons, and also allows you to not have to modify or even change either of the manifolds at all... at least not during initial testing phase. But if removing the pistons is out of the questions then I would remove the valves for those unused pistons, and instead of welding anything shut I would leave both intake and exhaust ports fully open to the atmosphere. Simply because that would create the least amount of power loss, but this would require modified manifolds... Or I would remove only the exhaust valve so that I can still use my factory intake manifold without any modifications and only have to deal with the exhaust manifold... and this would do what you stated, pushing and pulling air out of the exhaust port. Good Luck on your project!