My 05 hemi QC gets a solid 17mpg or better on 87 or 89 straight gas. I have run the ethanol stuff too and have seen no better than 14.6. Ethanol sucks!

 

do you mean you ran straight ethanol or the 10% mixture?

 

we have owned a 06 ram 1500qc hemi thunderroad 20's w 392 gears for two months. mileage have varied from 20.3 on a 300 miles trip, to 12.6 on 200 miles of city. also it seems that mileage is 2-3mpg better with 89 vs 87 octane. no mods on my machine. best mileage at 61-64 mph. rpms 1600-1800. drive smoothly with egg under shoe. use accelerator pedal instead of resume button to get back to set speed. still wish there was a mds indicator lite to help modify driving style to maximize mds usage.

 

The best way to get more mpg is to take all the money you would spend on all the mods for gas savings and buy a $1500 gas saver. I had my Geo paid for in about 8 months with the gas savings but then my wife puts down about 400-500 miles a week. If you don't want to do that then put black tape over the fuel gauge and enjoy the truck!

 

Ok, so I see everyone stuck on octane rating of gasoline and the addition of ethanol reducing the octane rating of gasoline.

Ethanol Otherwise known as ethyl alcohol or "alcohol," or "grain-spirits." Ethanol can be produced chemically from ethylene or biologically from the fermentation of various sugars from carbohydrates found in agricultural crops and cellulosic residues from crops or wood. Used in the United States as a gasoline octane enhancer and oxygenate, it increases octane 2.5 to 3.0 numbers at ten percent concentration. Ethanol also can be used in higher concentration in vehicles optimized for its use.

Oxygenated Fuels Literally meaning any fuel substance containing oxygen, the term is commonly taken to cover fuels containing such oxygen-bearing compounds as ethanol, methanol, MTBE or other oxygenate. Oxygenated fuel tends to give a more complete combustion of its carbon into carbon dioxide rather than monoxide to reduce air pollution from exhaust emissions.

Octane is a measure of how well a fuel resists premature combustion, or “knocking.� Gasoline with too low an octane rating converts fuel to heat rather than power, making for less efficient fuel usage and reduced engine life.

On todays modern computer controlled, fuel injected engines, spark knock or detonation is monitored, and the engine computer will learn over time to give more spark advance with the consistent use of higher octane fuels. This is usually not a one tank fix.

By these definitions, gasoline with ethanol will be 2-3 points higher in octane rating vs non-oxygenated fuels. Granted, Ethanol contains less energy per pound that gasoline, but the oxygen it carries to the combustion chamber would offset the reduced power. Alcohol engines will use ~20% more fuel per HP than pure gasoline engines.

If you really want to learn about fuel injection and how computers control fuel and spark, then look here. I've built, tuned and am currently running two of these systems.

www.msefi.com


Steve

 

MPG – first dodge trucks have not been known to be fuel economy champs. I own two. I would like more mpg too. Will the cost of any and all modifications actually pay the difference? I drive conservable and never get close to some of the mileage reported on here. I check my mileage with fuel receipts and actual mileage. I would think that you guys that get 20 miles to the gallon with a Ram should just go back to sleep and finish that dream.

Maybe I’m wrong or maybe not?

 

Thank you for the information on ethanol and oxygenated fuels. I re-read the R&T article I mentioned, and the author was only looking at chemical energy, stating that ethanol contains 68% of the energy as 87 octane. He extended that by stating that this means ethanol only gets your vehicle 68% of the distance for equal amounts. He did NOT address the improved efficiency of the engine. I will take a look at your link soon. Thanks for the valuable insight!

 

Last year I was doing mostly highway driving - upwards of 80%. I tracked the cost of the mods versus gains, and I believe that with highway driving I was seeing and cost-justifying the cost of CAI, dual exhaust, and hypertech programmer. (I have since taken off the dual exhaust, to reconfigure it.)
I agree. I never got close to 20.... 18 a couple of times, when conditions were perfect. Of course, once I installed bigger tires, I took a big hit on mileage even on the highway.

But this year, I am doing probably 60% local driving, and I can't tell the difference.

I mentioned to my father-in-law tonight something about gas mileage. After driving pick-ups for 40 years, he knows only that it's the most useful kind of vehicle, and there's no way you're going to get "good" gas mileage, so why waste the time? But for me it's always been an obsession - I like numbers, and figuring out ways to save money is key with a big family.

 

I'm getting about 18-19 MPG on my 2006 megacab 2500 CTD running unloaded on the highway.

There are certain limits on the mileage you can get from a gasoline engine. Catalytic converters and old style O2 sensors function best at about 14.7 AFR or Stoichometric mixture. Gas engines can operate at light loads as lean as 16 ~16.5 AFR or VERY lean. This would overheat the cat very quickly and would dump a host of pollutants such as NO2 and such.

There are newer style O2 sensors that are true "wide band" and will give actual O2 readings, but older style O2 sensors are closer to a switch. they read rich, or lean, and the computer determines Stoich AFR by how many times the O2 sensor crosses from rich to lean in a given time.

To achieve real mileage numbers, take a hint from the past. Install a Vacuum gauge, and drive seeking the highest vacuum readings. High vacuum readings indicate lightest engine load, and therefore best economy.

You could spend hundreds of dollars buying chips and intake kits and all that, but these companies usually have one thing in mind. separating you from your dollar as quickly as possible. I find it hard to believe that these companies have the research facilities and staff to REALLY improve what the manufacturer has determined to be the best combination of performance and economy for a particular vehicle. Instead, they use slick marketing tactics to seduce you into buying their products.

Lets take a look at what goes into a new chip. The company modifies the original fuelling and ignition map by adding a bit more fuel and changing the ignition curve slightly. They then burn this new program onto a chip that costs about $4.00 to $5.00. They spend a day on the dyno costing a couple of hundred dollars. They have maybe $1000 invested in development, and $6.00 in materials per chip, and you pay $300-$500 for that there chip. The technology for erasing and burning chips is widely available. They are taking advantage of your ignorance.

As always, Caveat Emptor. Let the buyer beware.

Steve

 

Ok first off the 06'+ models should be excluded from this thread. Im not saying it out of spite or dislike but because you can not compare the results your getting with your 06' models that have MDS and and the earlier models that dont have this option. The guy that started this thread shows that he has an 03' with the HEMI which does not have the MDS feature so any of you who are stating that your 06' is getting these high 18, 19, 20mpg+ really cant have that much of a say in what he should do to get the mileage you are getting unless you have owned and driven and applied these mods to an older RAM that didnt have the MDS. Do the mods like an exhaust, intake, and programer work yes, They do increase power and mpg gains however for the 06' Rams with MDS the gains for MPG are going to differ dramatically from those of us who do not have that feature.