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Have had the Flashpaq for a month or so and have experimented with high octane tune and economy setting. Some seat of the pants evidence as to the high octane tuning effect, but nothing overly dramatic. The surprise came on the last tank of fuel with economy setting where we experienced a drop in mileage by about 2-3 mpg? I'm considering a test with fewer variables related to type of driving, but a bit disapointed at this point.
 

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When you change the tune you need to let the ecu recalibrate the fuel mixture by driving for a while (one or two tanks of fuel). I never had luck at all using the econo tune however.
 

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I did some very unscientific testing, running the same 50 mile loop on the 87 performance tune, the 91 performance tune, the economy tune, and the stock tune with my Flashpaq, checking the amount drained from the tank each time rather than relying on the EVIC reading. From my tests they were all within 0.5 mpg of each other, and definitely within the margin of error. However, after months of driving, switching between tunes as needed, I noticed that the economy tune does move the shift points. It seems to shift more aggressively than stock, but far less aggressively than performance tunes, so I saw marginal improvements in city driving.
 

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Discussion Starter #4
I did some very unscientific testing, running the same 50 mile loop on the 87 performance tune, the 91 performance tune, the economy tune, and the stock tune with my Flashpaq, checking the amount drained from the tank each time rather than relying on the EVIC reading. From my tests they were all within 0.5 mpg of each other, and definitely within the margin of error. However, after months of driving, switching between tunes as needed, I noticed that the economy tune does move the shift points. It seems to shift more aggressively than stock, but far less aggressively than performance tunes, so I saw marginal improvements in city driving.
I'm definitely going to give it more time and make more comparisons. What makes this even more strange is that we noticed a slight uptick in mileage using the 91 octane tune....maybe the engine is more efficient with that fuel?
 

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I'm definitely going to give it more time and make more comparisons. What makes this even more strange is that we noticed a slight uptick in mileage using the 91 octane tune....maybe the engine is more efficient with that fuel?
It doesn't surprise me that you'll see better mileage with a higher octane fuel. A higher octane fuel contains more energy, so less of it will be used turning the engine. You'll see horsepower gains in the higher RPMs because of the extra energy, and at normal driving pace you'll be burning less fuel to keep the wheels turning. The tradeoff is the extra fuel cost, so unless you want the extra power of high octane fuel, you'll likely be better off saving 20+ cents per gallon using 87 octane.
 

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Discussion Starter #6
It doesn't surprise me that you'll see better mileage with a higher octane fuel. A higher octane fuel contains more energy, so less of it will be used turning the engine. You'll see horsepower gains in the higher RPMs because of the extra energy, and at normal driving pace you'll be burning less fuel to keep the wheels turning. The tradeoff is the extra fuel cost, so unless you want the extra power of high octane fuel, you'll likely be better off saving 20+ cents per gallon using 87 octane.
I'll buy that, though I don't think fuel grades are related to btu's.
 

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I'll buy that, though I don't think fuel grades are related to btu's.
You're right, I was trying to simplify things. The better description is that higher octane fuel is more efficient in the sense that it's more difficult to detonate. A higher octane fuel allows for a much higher compression in each cylinder before it detonates, and more compression leads to a more powerful detonation. I'm not an expert on how the FlashPaq adjusts settings to handle the 91 octane fuel, but I would guess it adjusts fuel ratios and spark timing to take full advantage of the high octane.
 

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Have had the Flashpaq for a month or so and have experimented with high octane tune and economy setting. Some seat of the pants evidence as to the high octane tuning effect, but nothing overly dramatic. The surprise came on the last tank of fuel with economy setting where we experienced a drop in mileage by about 2-3 mpg? I'm considering a test with fewer variables related to type of driving, but a bit disapointed at this point.
Can you be a little more specific Kaiser?

Which Superchips Flaspaq do you have?
 

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Discussion Starter #10
You're right, I was trying to simplify things. The better description is that higher octane fuel is more efficient in the sense that it's more difficult to detonate. A higher octane fuel allows for a much higher compression in each cylinder before it detonates, and more compression leads to a more powerful detonation. I'm not an expert on how the FlashPaq adjusts settings to handle the 91 octane fuel, but I would guess it adjusts fuel ratios and spark timing to take full advantage of the high octane.
Good explanation. I wonder if in fact cylinder pressures are higher due to the tune.
 

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That's the same one I have and I don't ever recall seeing an economy tune anywhere.

Then again, I never really looked for it either, I pretty much switch back and forth between the towing tune and the 93 octane performance tune.
 

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I tuned mine to the regular octane since the eco felt slugish and I have gain from 1 to 1.5mpg in my city highway mixed driving my highway driving for long distance still sucks I was never able to get more than 15.5 mpg driving speed limint 70 to 75mpg.
 

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My gas mileage has always been horrendous, maxing out around 10 city and 14 highway under normal driving conditions. I saw no major difference in any Flashpaq tune, though I never did try the 91 tune for a long time. I've never tried to hypermile with the tuner, but I have been able to average as high as 20mpg on the stock tune on a 150 mile trip by doing 50-55 on the freeway. I guess that's what MDS likes.
 

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Consumedbywater those mileage figures seem low to me. I consistently get 14.8 to 16.8 on the highway (determined by which way the wind is blowing) at 78 or better MPH here in the Midwest. I use the cruise control and are running Castrol Edge 5W20 High Mileage full syn. & mid-grade pump fuel. I try to run top tier certified gas. All maintenance items are current on my rig with a standard Wix air filter and spark plugs changed out with factory spec'd Champions at 95K. My MDS (fuel saver) comes on at these speeds on a flat surface, downhill, or with a tail wind. Current mileage 109+K. I'm running Michelin Defender LTX M/S in the stock size & no lift kit.
 

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I'm aware that my mileage is low, even for a Hemi. It's been this way since I got it at 110k miles, and apart from the low mileage it's in perfect running condition.

I run 5W20 Castrol GTX high mileage, a Mobil1 filter, and currently Champion iridium spark plugs, though I've run copper plugs in the past as well. My mileage improves around 1/2 mpg on mid tier gas, not enough to warrant the extra cost, but I always run top tier. I'm currently running a 2" lift and have my roof basket on, which does hurt mileage on the top end, but at 70+ has very little effect.

I've had Bridgestone Dueler H/L Alenzas in the stock size, and got significantly worse mileage on those highway tires than my 245/70 Grabber AT2s. I've also recently gotten a set of 26570R18 Nitto Terra Grapplers and get almost identical mileage to my Grabbers.

No matter what I try, my mileage never improves. My engine is healthy, my drivetrain is functioning properly, and I've tried everything to improve mileage, from the tuner to porting my throttle body to eliminating the restrictive stock muffler, and nothing seems to have any impact. At this point I've given up on improving it, since I can't come up with any reason why it should be as low as it is.
 

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Discussion Starter #16
That's the same one I have and I don't ever recall seeing an economy tune anywhere.

Then again, I never really looked for it either, I pretty much switch back and forth between the towing tune and the 93 octane performance tune.
Big Blue, you're right in that the tune I was referring to is not labeled "economy", but "Mileage XS save", shot of the Tune screen on Flashpaq attached.
 

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Discussion Starter #17
My gas mileage has always been horrendous, maxing out around 10 city and 14 highway under normal driving conditions. I saw no major difference in any Flashpaq tune, though I never did try the 91 tune for a long time. I've never tried to hypermile with the tuner, but I have been able to average as high as 20mpg on the stock tune on a 150 mile trip by doing 50-55 on the freeway. I guess that's what MDS likes.
Those are very similar to what we see. Only under perfect conditions, flat road, 60-65 mph can we see anything over 14 on the highway.

I should add that the mileage has improved now that we are in the second week or so of this tune. It has come up 1.5-2 mpg, all town driving.
 

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Big Blue, you're right in that the tune I was referring to is not labeled "economy", but "Mileage XS save", shot of the Tune screen on Flashpaq attached.
I'm 99% sure I don't have that option for whatever reason.

I'll have to plug mine in later and take a pic of the tuning options it gives me.
 

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Good explanation. I wonder if in fact cylinder pressures are higher due to the tune.
The tune can not change the compression, however, the change in fuel and ignition timing could possibly equate too higher pressure within the cylinder upon detonation. I do not think it is significant but, it may be enough to feel "by the seat of your pants" in a lower HP engine like the Commander has.
 

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Big Blue, you're right in that the tune I was referring to is not labeled "economy", but "Mileage XS save", shot of the Tune screen on Flashpaq attached.
I'm going to solve this riddle when I get home in about 2 weeks and I'll follow up with you @Kaiser.

I really don't remember seeing that option on my Flashpaq - but then again, I'm getting older.....LOL.
 
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