I ran seven tanks of non-ethanol Fastrack 91 octane gasoline through the Ram over a 36 day period starting in late August of this year. Since most of those miles were around town I could not use them for my test. However, I used the non-ethanol fuel on three September, 126 mile trips to my property in the Southerntier which I can compare with thirty-two previous trips I've taken over the years carrying my 800 lb. ATV, and sometimes a chainsaw.

Since weather has a bearing on fuel consumption, I compared the three trips using non-ethanol to trips during the same period in 2010, 2011, and 2012. The three year average of all trips during September time frame is 17.73. The best of these trips was 18.81 (June 2011).

Using non-ethanol Fastrack fuel, carrying the ATV on the 126 mile round trip, the Ram returned the following: 20.91 (9/2), 20.13 (9/21), and 20.26 (9/29). These are the highest gas mileage numbers I've ever recorded on this course.

I was also able to compare one 420 mile round trip to south central New York state and back with just one passenger. These trips were over US20, NY13, NY80, NY23, NY205, NY28, back to US20. Anyone familiar with this part of New York knows its pretty up and down hilly. Using 87 Sunoco my previous trip on this path returned 22.51 MPG in September of 2011. On this last trip the Ram returned 24.48 MPG on the non-ethanol Fastrack 91. This is also the best fuel mileage I've ever recorded on this truck.

Of course, this little test of mine is only indicative, but still not completely conclusive since driving conditions on these courses cannot be held to a perfect constant. I typically drive these courses at the posted speed limits, but speed often varies with traffic flow. Nothing can be a better test than a closed course.

Ethanol contains approximately 34% less energy per unit volume than gasoline. However, ethanol has a higher octane rating, so engines can be made more efficient by raising compression ratio. In documented tests, ten percent ethanol fuels (E10) produces approximately 3-4% less energy over ethanol fuels.

One thing is clearly evident. In my Ram the engine performance increase was noticeable using the non-ethanol Fastrack 91, producing smoother and lower shift points, a smoother idle, and ability to stay in the ECO mode longer during acceleration.

Best regards,
Dusty

2010 Ram Big Horn 1500 Quad Cab 2WD, 5.7 Hemi, 545RFE, 3.92 LSD, factory dual exhaust, 20” wheels. Now at: 91,000 miles.

 

Great example of why the window sticker says this truck will get between 16 and 24 MPG highway.

 

not at all surprised by your dads mileage. I don'tr know of any 3/4 truck, big crew cab that gets any kind of mileage, the weight gearing and all. They're not made for it. You don't say what gears you have but I don't know what the TRX4 is. Is it half ton?I assume 4 wheel drive. But I do know theres a lot of differance from 09 to 12 not sure where the 2010 is but I have a 2012 gighorn, 1/2 ton, 20" wheels, 2 wheel drive no mods but a cold air intake that I pd $300 for adn would sell for $150 today and put the stock intake back on if that gives you any idea how much it helps. Its a K&N. I have a pretty heavy foot especially in the highway, 80-85 most of the tims and get from 18-20 on the highway at 80-85 anyday. If I pussyfoot around on the highway at sa y60-65 it will give me 20-23 anytime. In town? I do house to house in my business, constant stop & go, I tend to take t a little easier in town and get on an average 17 every tank full. So my guess is, if the 10 is the same as the 12, does it have the 6 speed? oh, I have 3.92 gears which everyone says is hard on gas, I don't see it. Like I said if the 10 is the same as the 12 and its 2 wheel drive, I'd take those big tires off and maybe consider going back stock on the intake, don't know much about the throttle body and maybe try getting out of the gas a little!! If I ant to push mine around town I can get 14 but thats really pushing it.

 

I have to echo a lot of what Tunaman has written. I think you've made a lot of changes that are aimed at performance and looks, but very detrimental to fuel economy.

After talking to tens of guys who have installed a low restrictive air filter system, most are surprised and disappointed in the negative effects on fuel consumption. Low restriction air filter and intake systems are really designed to reduce air flow impedance at the extreme upper end of engine demand, and as such will generally offer only improved high RPM performance over the original design.

I suspect that the tires you've installed has contributed to increased rolling resistance and inertia losses. The heavier the tire, the more work is required from the engine to spin it up to speed. This may be especially acute if you are still using a higher axle ratio, like 3.55s, because the engine will be operating more with increased throttle pressure. (When you increase the load on the engine the throttle plate must be opened more to keep power up thereby using more fuel.)

The larger throttlebody may or may not be an issue (I believe the stock 2010 Hemi throttlebody is 80 or 82mm). When you alter the throttlebody size the Throttle Position Sensor should be recalibrated or else you may realize performance loss at certain throttle angles because the engine computer determines fuel injector pulse width based on the angle of sweep of the original sensor.

The change in tire diameter from stock has produced a odometer/speedometer error. If you haven't done so already, I recommend checking it against a known distance (GPS devices are great for this).

Lastly, aside from the effects of your personal driving style, you may not realize any benefit from different fuels because when the baseline for MPG is at lower numbers (i.e.: 10 mpg), even a 10% change either way (one mile per gallon) is most likely within the normal variation, and you wouldn't recognize it unless you did a long term manual tracking of fuel usage of time. Even then I doubt you'd see it because its highly unlikely you drive the same course, distance, and speed every time.

On the upside you sure do have a nice truck with significant eye appeal.

Best regards,
Dusty

 

To the best of my knowledge, I believe the TRX version is HD (3/4 & up).

Lower drive ratios reduce engine RPMs, and higher ratios reduce engine loading. Depending on driving conditions either may produce better efficiency (fuel efficiency). The general result is lower ratios provide better MPG at higher and steady highway speeds, but lose efficiency on start/stop, acceleration and load bearing. Conversely, higher ratios provide better MPG at lower speeds, acceleration, and higher load.

My results appear to be very similar to yours. I, too, have the 3.92 gear set with 20 inch tires, 2-wheel drive Quad Cab. Typically in summer my around town MPG varies between 17-19. On long distance country roads at 55 mph with little stopping I regularly see 20-22 quite easily. Expressway or interstate driving I find 65 mph producing 20-21 on average, depending on terrain. The numbers drop in the winter months, especially on short trip driving where I sometimes dip in to 14 mpg territory.

Bests,
Dusty
2010 Ram Big Horn 1500 Quad Cab 2WD, 5.7 Hemi, 545RFE, 3.92 LSD, factory dual exhaust, 20” wheels. Now at: 91,000 miles.

 

This is not really a good test: there will be a larger difference in the change in octane than the difference of with/without ethanol. Since our engines are designed to run on regular 87 octane, increasing it by using "premiuim" 91 octance is actually a detriment. It won't hurt the truck by any means, but since it will ignite later in the burn cycle it may not actually burn as completely before exhaust so you could potentially even lose power. Modern engines will compensate pretty well for this so you probably won't lose much if any power/mpg, but there's no reason to octane boost unless you have chipped or modded you engine.
I like the idea of this post, but it's not an apples to apples comparison. You are right to assume that gas with the same octane rating without any ethanol will definately make more power than with. They are cheating us at the pump. If anyone can fine 87 without ethanol, let me know where!

 

Thanks for the post. One minor point: the 5.7 Hemi in Ram trucks are actually designed to run on 89 octane. As with most systems of this type, when using 87 octane the ignition timing is retarded accordingly. Whether the engine controls will provide a more advanced timing for octanes greater than 89 is possible, but not known at this time.

Best regards,
Dusty
2010 Ram Big Horn 1500 Quad Cab 2WD, 5.7 Hemi, 545RFE, 3.92 LSD, factory dual exhaust, 20” wheels. Now at: 101,000 miles.

 

Whether the engine controls will provide a more advanced timing for octanes greater than 89 is possible, but not known at this time.



I believe this it is well known that the stock engine control wont provide a more advanced timing for octanes greater than 89 .It might be possible but its not happening right now If it would there would be no need for tuners, since if it would provide for higher octanes, it would give us a different performance tune, and we all know that that isn't happening. You will see no gains in performance by using higher than 89 octane, unless you have a performance tune that requires a higher octane fuel. Question for you Dusty....where your mileage tests based upon an American gallon or Canadian gallon?

 

As an American: "what's a Canadian gallon? Is that like a liter (or litre)?"

 

Canadian measurements are based on the metric system ,back in the day the US did not convert over to metric but kept there US measures ,so in metric a US gallon is 3.75 liters and a Canadian gallon is 4.5 liters .