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A question about the new HEMI and MDS

2002 Views 9 Replies 7 Participants Last post by  JSA 007
Hey everybody this is my first time posting at these forums, which are quite nice btw.

I've been reading up on the new HEMI quite a bit lately, more specifically MDS, but I haven't found out too much other than that it turns off 4 cylinders when the engine is not under load.

This question is more to satisfy technical curiousities more than anything. But I was wondering if MDS when activated (by that I mean 4 cylinders running, and four off) would cycle through the avaible 8 cylinders. By that I mean does MDS alternate which 4 cylinders recieve power during a stroke of the engine, or does the engine simply turn off the SAME 4 cylinders everytime MDS is activated.

Thanks for any insight
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Manris said:
I know the cylinders don't shutoff, but they aren't supplied with the means to make power... they aren't supplied with fuel and a spark, but air does pass through them.
Actually, the system deactivates the valves and they remain closed. Any air/fuel that is "caught" in the cylinder is compressed and recompressed over and over, this creates a "spring" action that helps keep the pistons moving. Most likely there is also some factor of blow-by (air/fuel mix seapage past the rings) but probably very minimal. Since the computer shuts the spark off there is no ignition.

BTW - Welcome to the forum.
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