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-   -   5.7 L ECO quesstion (http://www.jeepgarage.org/f73/5-7-l-eco-quesstion-18327.html)

2011RitterGC 02-02-2011 04:37 PM

5.7 L ECO quesstion
 
When the 5.7 L goes into ECO mode and cuts off 4 cyl. Does it cut off the same 4 every time or does it switch from one set of 4 to the other?

NetJunkie 02-02-2011 04:40 PM

Re: 5.7 L ECO quesstion
 
It constantly alternates. So 4 fires, then on the next cycle the other 4 fire. This keeps wear/temp/balance the same.

2011RitterGC 02-02-2011 04:46 PM

Re: 5.7 L ECO quesstion
 
Quote:

Originally Posted by NetJunkie (Post 346876)
It constantly alternates. So 4 fires, then on the next cycle the other 4 fire. This keeps wear/temp/balance the same.

Thanks. I was hoping that was the case.

TAZ28 02-02-2011 04:49 PM

Re: 5.7 L ECO quesstion
 
Wow! I never thought of that. Great question! Awesome answer! Good to know..

voyagerx 02-02-2011 05:04 PM

Re: 5.7 L ECO quesstion
 
According to allpar:

Chrysler engineer Cole wrote: "The modern Hemi always shuts off the same four cylinders. In our duarability test cycle (150,000 customer equivelant miles driven at the 95th percentile, meaning that only 5 percent of our owners are more abusive than our testing), we have not found any adverse wear patterns." Even in 2010, five years later, there have been no reports of problematic uneven wear.

http://www.allpar.com/mopar/new-mopar-hemi.html

JTS97Z28 02-02-2011 05:14 PM

Re: 5.7 L ECO quesstion
 
Ok lol one guys says one thing and another says something different.

Marlin 02-02-2011 05:28 PM

Re: 5.7 L ECO quesstion
 
Same 4 cylinders are shut down, and they are "lit' every ten seconds to keep temperatures even and plugs clean.

bpmcgee 02-02-2011 05:29 PM

Re: 5.7 L ECO quesstion
 
I believe Voyager, and I base that on the technical details of HOW they disable the cylinders.

They do so by shutting off the oil to the hydraulic lifters of the exhaust valves, allowing the lifters to deflate, and keeping the exhaust valves shut.

If they were alternating cylinders, then at 3000 RPM they'd have to be able to inflate a lifter in .02 seconds, which is several orders of magnitude faster than they can ACTUALLY inflate.

B

2011RitterGC 02-02-2011 06:40 PM

Re: 5.7 L ECO quesstion
 
Quote:

Originally Posted by bpmcgee (Post 346909)
I believe Voyager, and I base that on the technical details of HOW they disable the cylinders.

They do so by shutting off the oil to the hydraulic lifters of the exhaust valves, allowing the lifters to deflate, and keeping the exhaust valves shut.

If they were alternating cylinders, then at 3000 RPM they'd have to be able to inflate a lifter in .02 seconds, which is several orders of magnitude faster than they can ACTUALLY inflate.

B

Why?? If you are "turning back on" 4 cly why would it matter which 4?

NetJunkie 02-02-2011 09:27 PM

Re: 5.7 L ECO quesstion
 
Guess I'm wrong! :) Sorry about that. I read my answer somewhere else a while back..I think when we got our MDS-enabled Commander. Interesting.

mrpositraction 02-04-2011 08:56 AM

Re: 5.7 L ECO quesstion
 
Quote:

Originally Posted by 2011RitterGC (Post 346957)
Why?? If you are "turning back on" 4 cly why would it matter which 4?

It is about the mechanics of it, not playing favorites of which cylinders. It is mechanically easier to do the same 4 than alternate the cylinders.

jeep2011 02-04-2011 09:10 AM

Re: 5.7 L ECO quesstion
 
Also there has been numerous posts. ECO doesn't always mean cylinder deactivation mode. If you are meeting the requirements of economic driving (ie getting great gas mileage) the ECO light turns on.

http://www.jeepgarage.org/showthread...&highlight=eco


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