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Does anyone know of a tune for 2017 SRT that would improve MPG? I saw some for older Challengers, but couldn't find anything for mine. My thinking is that when I want to drive for fun, I can pop into track or sport mode and enjoy all the performance I get out of the car, but when I am commuting and sitting in stop and go traffic, I really don't need all the powar and all cylinders firing (MDS doesn't seem to engage on idle)...

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Basically the way the PCM works is if it sees the accelerate pedal voltage above ~3 volts it considers the engine is under WOT and refers to power enrichment tables which will richen up the mixture for more power. If the pedal voltage is below 3 volts it then the PCM target fuel economy. If you stay out of WOT the PCM adjusts fuel trims to constantly maintain stoich of 14.5:1. To potentially get better gas mileage in PT (part throttle) operation one could adjust for a leaner stoich but this means the engine will run hotter...something you don't want as heat kills performance. I doubt you will get noticeable fuel economy improvements to justify the ~$1K cost to do so (tuner cost+tune+unlocked PCM+voided warranty). Just stay off the throttle (slow and steady pedal movements) as much as you can during stop-go driving. You probably would see more fuel economy by airing up your tires and changing driving habits. Just my $0.02.

BTW you do not want MDS to engage at idle...the vibrations would drive you nuts.

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Discussion Starter #3
Basically the way the PCM works is if it sees the accelerate pedal voltage above ~3 volts it considers the engine is under WOT and refers to power enrichment tables which will richen up the mixture for more power. If the pedal voltage is below 3 volts it then the PCM target fuel economy. If you stay out of WOT the PCM adjusts fuel trims to constantly maintain stoich of 14.5:1. To potentially get better gas mileage in PT (part throttle) operation one could adjust for a leaner stoich but this means the engine will run hotter...something you don't want as heat kills performance. I doubt you will get noticeable fuel economy improvements to justify the ~$1K cost to do so (tuner cost+tune+unlocked PCM+voided warranty). Just stay off the throttle (slow and steady pedal movements) as much as you can during stop-go driving. You probably would see more fuel economy by airing up your tires and changing driving habits. Just my $0.02.

BTW you do not want MDS to engage at idle...the vibrations would drive you nuts.

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This is a lot more in depth than I expected. Thank you!
 

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Does anyone know of a tune for 2017 SRT that would improve MPG? I saw some for older Challengers, but couldn't find anything for mine. My thinking is that when I want to drive for fun, I can pop into track or sport mode and enjoy all the performance I get out of the car, but when I am commuting and sitting in stop and go traffic, I really don't need all the powar and all cylinders firing (MDS doesn't seem to engage on idle)...

Thanks!
At the risk of sounding pedantic, I am curious what kind of MPGs are you seeing now which you believe can be improved upon?

The reality of the situation is that you drive a car which weighs over 4000 lbs (closer to 4500 with you and a full tank of gas), and it is powered by the largest displacement fuel injected gas engine available in the platform. So while getting better MPGs is a noble endeavor, any actual gains you may achieve (regardless of how) will ultimately be relatively meager by anyone’s measure.

And as has been pointed out by @ChallyTatum already, adjusting the way you drive is going to be the quickest and easiest (not to mention cheapest) way to improve the gas mileage you see on that car. I base that conclusion on my own experiences driving my 5.7L-powered whale of a car.

I’ve seen as little as 11 MPG (immediately after acquiring car; during daily commutes of 3 hrs to/from work in stop and go traffic) and high as 27 MPG (trip to Atlanta with MDS engaged), and at the moment I‘m averaging right in the middle - 19 MPG (combined city/highway). The difference from before and now? My driving habits...more specifically how much and how quickly I mash the gas pedal.

Your right foot is the key. It holds all the power, literally and figuratively. 🤓
 
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