MDS Support

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  • Idea
  • Updated 4 years ago
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I'd love to see you take the gas saving concept even further ... Chrysler (and others) have an MDS system that drops from 8-cylinders to 4-cylinders that is triggered by driving habits. The purchase would be a no-brainer if it could monitor MDS and have an indicator showing if it is on or off and how you can change your habits to keep it on as much as possible. I am getting ready to "hack" my wiring harness to add an LED on the dash just to know when it is activated to try and keep it on as much as possible. My Jeep gets 13MPG without it and 18MPG with it, so this feature alone would justify the cost of your device within a few months!
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Craig Myers

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Posted 4 years ago

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Ted, Former Employee

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Hi Craig!

This is a great feature suggestion-- I've been looking into the effects of fuel trim and Honda's VTEC system on fuel consumption (mentioned in this blog post: http://blog.automatic.com/cost-speedi...).

There's a similarly large MPG dropoff between being on cruise control in a VTEC car and accelerating/decelerating erratically-- I really like the idea of doing real-time alerts based on that!
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Myron Billiot

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I have a 2011 Ram 1500 with the HIMI v8.  I have a programmer with the ability to lock out the MDS mode and did a test.  With the MDS mode off, your device shows that a 32 mile trip cost me around 4 dollars and I average 21mpg.  With the MDS on, the same trip cost me over 6 dollars and I average 19mpg.  I have a range of 550 miles with the MDS on and 525 miles with the MDS off.  Your system is confused with the MDS mode on.  I ran the test a week at a time driving the same route to work so the averages and conditions are consistent.  
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Myron Billiot

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This reply was created from a merged topic originally titled
HIMI MDS.


I have a 2011 Ram 1500 with the HIMI v8. I have a programmer with the ability to lock out the MDS mode and did a test. With the MDS mode off, your device shows that a 32 mile trip cost me around 4 dollars and I average 21mpg. With the MDS on, the same trip cost me over 6 dollars and I average 19mpg. I have a range of 550 miles with the MDS on and 525 miles with the MDS off. Your system is confused with the MDS mode on. I ran the test a week at a time driving the same route to work so the averages and conditions are consistent.
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Tom, Former Employee

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Hi Myron. I'm sorry we missed your earlier post on this topic. I'm checking with the team for the latest information on MDS support and will let you know when I hear back.
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Tom, Former Employee

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Hi Myron. I spoke with our in-house technician, and the way in which we calculate fuel consumption for the Multi-displacement System (MDS) may have a bug. Automatic only looks at air intake to calculate MPG, so to us, it looks the same (or worse) because the vehicle is momentarily down on power. But from the vehicle side, it deactivates the spark and fuel but does not limit the air intake. 

We'll review your drive data and look into it further. Thanks again for sharing your input with us.

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