Killing individual cylinder ignition

[Frank Lee]

And lots and lots of welding. You know, for the nuclear debris benefits.

[Christ]

Originally Posted by Frank Lee

And lots and lots of welding. You know, for the nuclear debris benefits.

If the weight of the weld medium exceeds that of the engine....









You might drive an old ass subaru...

[Old Mechanic]

59 Bugeye Sprite with two burnt exhaust valves was seriously gutless.

35 PSI compression on those two cyls.

regards
Mech

[ahab13]

On my 91 Geo Storm 2 of the fuel injectors simultaneously went out, and even with the ECM in limp mode and the unnecessary drag of 2 useless pistons and everything I was still able to drive home about 25 miles using going about 50 on the freeway and almost stopping when going up hills. The Storm has speed density EFI so it goes off of RPM and TPS, and MAF which could be tricky with 2 cylinders. I'm not too sure about tricking it, but If you can figure that out then you should have a 800cc fuel sipper. If not you can just throw the carb on there, and still get really good mileage.

[Christ]

Originally Posted by ahab13

On my 91 Geo Storm 2 of the fuel injectors simultaneously went out, and even with the ECM in limp mode and the unnecessary drag of 2 useless pistons and everything I was still able to drive home about 25 miles using going about 50 on the freeway and almost stopping when going up hills. The Storm has speed density EFI so it goes off of RPM and TPS, and MAF which could be tricky with 2 cylinders. I'm not too sure about tricking it, but If you can figure that out then you should have a 800cc fuel sipper. If not you can just throw the carb on there, and still get really good mileage.

Thanks for this post, and informative for a first post here. There is a thread on going about this over here, please add your input there, as well!


Welcome to EM!

[guillermoariast]

Hello, i have a Chevrolet K5 Blazer 4x4 truck with a 6 cyl, 250 ci engine.
It is a carburted engine with electronic distributor.

I would like to know how to kill 2 cylinders when i'm on a plain road at constant velocity.

Thanks

[stonebreaker]

Just deactivating the injectors won't work. The problem is you're still pumping air through the engine, which requires work. The way the OEM's do it is they shut off the valves to the deactivated cylinders, so that the trapped air simply acts as a spring and you don't have the pumping losses. Even so, the OEM's are seeing only about a 15% increase in fuel economy with cylinder deactivation.

[guillermoariast]

Originally Posted by stonebreaker

Just deactivating the injectors won't work. The problem is you're still pumping air through the engine, which requires work. The way the OEM's do it is they shut off the valves to the deactivated cylinders, so that the trapped air simply acts as a spring and you don't have the pumping losses. Even so, the OEM's are seeing only about a 15% increase in fuel economy with cylinder deactivation.

Hi, thanks for answering. My engine is carburated. How could i (with help from my mechanic) do it?

[stonebreaker]

You can't. The engines with cylinder deactivation have to be designed that way from the factory. For example, the way GM does it in their LS series engines is by turning off oil flow to half the lifters, which causes them to collapse, thereby deactivating the valves. You'd have to get a brand new unmachined engine block and drill the oil passages yourself, fit electric solenoids in place, and program a computer when to activate it or not, in order to do that on a version of the engine you have now; you're better off just buying a junkyard motor that has it already.

A couple of places you CAN look for fuel economy improvements in your current setup might be in friction reduction. Is your motor an overhead cam engine or a pushrod engine? If it's a pushrod engine, look into roller rockers. These reduce internal engine friction. If an overhead cam, maybe check into camshaft roller bearings.

Another area to think about when you have to rebuild your engine is with new design pistons. get hypereutectic pistons with anti-friction coatings on the skirts and heat reflective coatings on the tops. Get the pistons that use the thinnest rings available. We've seen horsepower increases by as much as 20 hp just by going with these; all they do is reduce internal friction and keep more heat in the combustion chamber.

Maybe look at porting your exhaust ports. The faster the cylinder blows down after the exhaust valve opens, the less work the engine has to do pumping the exhaust out of the cylinder. I doubt intake porting would help much, but pocket porting the exhaust, especially to increase low lift flow, would certainly help make the engine more efficient.

You said your engine was carberated. If it is a pushrod engine, see if it has roller lifters. If not, think about converting. It will not only reduce internal friction but increase reliability, as well.

I realize you're never going to save enough gas to justify the more radical mods, but I'm coming at this from a performance viewpoint rather than a cost standpoint.