Cylinder deactivation discussion

[roflwaffle]

Yes and no... Depending. You can get the same effect more or less from using your left foot and right hand, with maybe some gearing changes.

[metroschultz]

Originally Posted by Frank Lee

1. REMOVING the con rod CREATES an unbalanced condition! Now the counterweights on the crank are too heavy if there's nothing on the throw. This is an attempt to re-balance. I've read that the bottom 1/2 of the rod's weight is used for balancing cranks.

2. Absolutely I do. I don't believe it causes problems.

"Oh duh grampa", My bad I hadn't thought of the weight versus counterbalances. I'm not really a troglodyte, I just sound like one sometimes.
S.

[Who]

Originally Posted by Peter7307

A quick quote from the Chrysler info pack when the vehicle was released:

"Chrysler C300 has a four cylinder / eight cylinder engine.
Four cylinders at normal running and eight on demand.
Utilising the four cylinder demand option results in a seven percent fuel saving."

I would have thought it would be more than that.

Pete.

Still have all the internal friction and it hasn't changed the actual loading... I'd rather have a better transmission. Especially when you consider at leats in the case of the Odyssey which was the only cyl-deact vehicle I've driven just how much other stuff is added including noise cancellation through the speakers... way too complex! Make the motor smaller, or some kind of on demand boost, but deactivation is too much complication and risk for too little gains IMHO.

[oldschool]

To me it would seem to be easier to create more power in a 4 cylinder when its needed , then it would to deactivate half the cylinders and drag them along, tryin to get a 10% improvement/.This to me has been shown particularly true with fuel injection.The early carbed v8 to v4 conversions got around 26 mpg with dummy pistons in the dead holes. If you don't use dummy pistons then you are dragging the rings along. especially if the valves are disabled, and creating both compression and vacumn situations the other 4 cylinders must fight against. In addition you are carrying a lot of unneccessary weight, that would net you free mileage. In my mind it was tryed and was a waste.

[cfg83]

Frank -

Originally Posted by Frank Lee

^YES and no!

It has been done before. I've seen where some college kids back in the day pulled 2 cyls. out of a VW Bug and coaxed 58 mpg out of it, IIRC.

This makes me think that a Subaru flat-four boxer would also be a candidate, since it is "naturally balanced", yes?

CarloSW2

[diesel_john]

good discussion modders. i just found out i have to grind the cam lobes off a bit because they hit even with the buckets out. the valves have worn down into the seat. i am thinking cut the rods off and take out the clearance, so they clamp on and can't turn. not much room between the rod and block. next i need decommisson two ports on the injector pump. that should be interesting. all rod throws are individually counter weighted on this crank.
How many votes for even fire, uneven balance?
How many votes for even balance, uneven fire?


1.6 D short block
1.6 D head
third pic is for comic relief.

[metroschultz]

I vote for even fire. You can re-balance later as needed.
S.

[Frank Lee]

Originally Posted by oldschool

To me it would seem to be easier to create more power in a 4 cylinder when its needed , then it would to deactivate half the cylinders and drag them along, tryin to get a 10% improvement/.This to me has been shown particularly true with fuel injection.The early carbed v8 to v4 conversions got around 26 mpg with dummy pistons in the dead holes. If you don't use dummy pistons then you are dragging the rings along. especially if the valves are disabled, and creating both compression and vacumn situations the other 4 cylinders must fight against. In addition you are carrying a lot of unneccessary weight, that would net you free mileage. In my mind it was tryed and was a waste.

If all it is good for is 10% I wouldn't futz with it either. I have seen evidence it can be worth more.

What kinda damn fool would drag 4 dead pistons around in a V4 conversion??? No way would I do that, rings gone or not. Imagine the massive rushes of air past the pistons in both directions without rings! That takes ENERGY.

Yes, if that's what they tried it was a waste.

[Frank Lee]

Originally Posted by cfg83

Frank -
This makes me think that a Subaru flat-four boxer would also be a candidate, since it is "naturally balanced", yes?

CarloSW2

I'd guess it would be equal to the VW. As far as naturally balanced, the flat fours still have counterweights on the crank; but flat sixes don't, making them truly naturally balanced.

[Peter7307]

Originally Posted by Who

Still have all the internal friction and it hasn't changed the actual loading... I'd rather have a better transmission. Especially when you consider at leats in the case of the Odyssey which was the only cyl-deact vehicle I've driven just how much other stuff is added including noise cancellation through the speakers... way too complex! Make the motor smaller, or some kind of on demand boost, but deactivation is too much complication and risk for too little gains IMHO.

Totally agree.
A smaller four with super / turbocharger would have been a better choice in my opinion.

Pete.