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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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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.

View attachment 980278
This is a lot more in depth than I expected. Thank you!
 

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2012 Charger Pursuit
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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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Old post but how might timing affect it?
An adjustment in timing won’t have much effect on MPGs, if the amount of adjustment is reasonable.

If it’s not a reasonable amount of timing adjustment, it would definitely have an effect on MPGs - they would go down...probably by quite a bit.
 

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Engine temp? Would a 180 stat hurt?
From the standpoint of MPGs, and assuming the local climate is not exceedingly cold most of the year, a cooler running engine should help with mileage.

The 180F thermostats help with power production for the same reason(s), but more power doesn’t usually mean better MPGs, especially with this crowd.

I will say I’ve personally switched to a 195F thermostat in my 5.7L (with plans of going to 180F when spring sets in), and I’ve noticed no appreciable change in MPGs since doing so.

The quickest and easiest (?) mechanical mod to gain a couple MPGs is probably raising the gear ratio in the rear end. There are no free lunches though, so a higher gear out back means less acceleration off the line, but with almost 500 TQ in the 6.4L cars (not to mention the relatively skinny tires), less wheel spin off the line could be a welcome change to the tire-boiling experience currently had.
 

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I thought there were papers showing engines running around 200F was more efficient and produced less emissions?
 

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I thought there were papers showing engines running around 200F was more efficient and produced less emissions?
In the last 7 days (nights) I’ve made 7 trips up to Lake Ray Hubbard and taken advantage of a pair of really long and straight bridges I found while out scouting for, well, exactly such structures, and each trip saw no less than 5 stints at WOT that usually spanned 3 gears on average.

While my engine may normally run very close to 200F, it has not been seeing much normal operation lately. So I cannot speak to the accuracy or even applicability of such papers in real world scenarios. I can only say that before the 195F thermostat I got about 21 MPG on the EVIC meter, and that didn’t change after it was installed.

Here lately it is only reaching about 19 MPG on each tank, but I suspect that’s due to the lower rear gears I’m running now (3.06 vs 2.65).
 

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Leave the stock thermostat . get a tune . all tunes will advance the timing some and then drive like there’s a raw egg under your right foot .
 

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I thought there were papers showing engines running around 200F was more efficient and produced less emissions?
One of my references lists engine wear vs. engine temperature and wear goes up as temperature goes down.

If there is wear there is friction and friction wastes energy.

I have to also point out a cooler engine will have cooler oil and cooler oil takes more energy to pump which also wastes energy. And cooler oil is more viscous which is also creates internal engine drag.

Last but not least given the penalty for higher emissions and high fuel consumption if these engines were more efficient colder they'd run colder from the factory. Dodge or for that matter any other car maker would not leave anything on the table that would help with lowering emissions and reducing fuel consumption.
 
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