Hey all,

I've heard mixed raves about the Ecoboost and using Premium fuel greatly enhancing the preformance and slightly increasing MPG but has anyone done any real studies to see if the Midgrade 89 Octane rating vs the Premium 91 (I believe these are the number ratings in Iowa) show any real results?

Is it worth the extra 20 cents a gallon, does it pay you back in the long run?

Any thoughts as if it does make a bit of difference I'd be glad to start using it only if the whopping 2+ Octane rating makes a difference.

 

I don't think you'll see any difference in MPGs going from 89-91.
IMO, if you can find some gas without 10% ethanol in it (regardless of octane) that would make the biggest difference. Ethanol-free gas stations in the U.S. and Canada

Unfortunately it's too far for me to travel to get ethanol free gas.

 

A guy on another forum claims that his Ecoboost Edge gets 10% better mileage with premium priced around 5% more per gallon.

 

I've been running super instead of regular for these last 2 tanks and it appears to have gained me 1.6 MPG so far.

 

This is an interesting thought. I can't imagine getting better MPG's out of my truck daily or traveling but the possibility of a 10%+ gain is tempting. Premium is what regular was a couple of months ago, now is the time to experiment.

 

from the financial side of things its usually a wash. Cost you 10% more to get 10% better economy. Only bonus to it would be proving that its doing your motor some favors.

 

From what I understand the manual does state to increase your octane when towing. If you are not towing...I agree with what 96sherm said...if the truck really does not need it unless towing, paying more for fuel to get another 1 mpg doesn't make sense to me.

 

As long as you break even (equal cost per mile), there's no reason not to run premium. The motor will be a bit happier and you'll have a bit more power on tap.

 

Premium (and mid-grade) fuel does not have any additional energy per volume (providing they both have the same ethanol content).

It does however, allow the PCM to advance the timing. If you typically drive with a heavy right foot or do a lot of towing (and continue to after filiing up with premium), then the increase in power MAY help your MPG.

Another very likely contributor to the apparent increase is your driving habits. Subconsciously (or even consciously) you have altered your driving habits knowing you just spent 10-15% MORE for that tank of gas.

In other words, if you drive the same, under the same load conditions, and under in the same environment, premium (and mid-grade) will not increase your MPG.

EDIT:

Even the gasoline manufacturers do not recommend higher octane as a way to increase MPG.

Gasoline Information, Octane Levels - Exxon.com

 

Mike from 5-star tuning (which also coincides with what it says in the manual) specifically told me that the ECU has two maps programmed in it; one for 89 octane and one for 91. The ECU is very good about listening for knock and advancing timing with 91 octane, which in return yields more power and better fuel economy. Running 93 on the other hand would be pointless since there's no map for it.

 

It doesn't matter WHAT the gas companies say about what octane level you need to run; the only thing that actually matters is the engine's static compression ratio and how much the ECU is advancing timing. High compression ratio and/or more timing advance requires higher octane, while a lower compression ratio and/or less ignition timing requires lower octane fuel. Simple as that.

 

I have now towed with premium and with regular - the result is that I ended up with an average of 9.8 mpg using premium vs. 10.3 mpg with regular. Not very scientific because the two trips were to a different destination - but overall same elevation gain of zero. I account this difference to wind differences, and whatever else. I think it does not make much of a difference, and is probably a waste of time to even think about, LOL. The truck tows very well with regular, does not knock, so I think that's what it will be.

 

I my mind the only time you would need it is towing...otherwise it is a waste of money....however to each his or her own!

 

Sorry, but you clearly do not understand the concept of octane and energy content. As a result the



has been thrown.

Octane rating - Wikipedia, the free encyclopedia

Gasoline gallon equivalent - Wikipedia, the free encyclopedia

GGE - Gasoline Gallon Equivalent (US Gallons) tables

<TABLE class="wikitable sortable jquery-tablesorter"><CAPTION>GGE Calculated for Gasoline in US Gallons at 114,000 BTU per Gallon</CAPTION><THEAD><TR><TH class=headerSort title="Sort ascending">Fuel - Liquid, US Gallons</TH><TH class=headerSort title="Sort ascending">GGE</TH><TH class=headerSort title="Sort ascending">GGE %</TH><TH class=headerSort title="Sort ascending">BTU/Gal</TH><TH class=headerSort title="Sort ascending">kWh/Gal</TH></TR></THEAD><TBODY><TR><TD>Gasoline (base)<SUP id=cite_ref-epa_1-0 class=reference>[2]</SUP></TD><TD align=right>1.0000</TD><TD align=right>100.00%</TD><TD align=right>114,000</TD><TD align=right>33.41</TD></TR><TR><TD>Gasoline (conventional, summer)<SUP id=cite_ref-epa_1-1 class=reference>[2]</SUP></TD><TD align=right>0.9960</TD><TD align=right>100.40%</TD><TD align=right>114,500</TD><TD align=right>33.56</TD></TR><TR><TD>Gasoline (conventional, winter)<SUP id=cite_ref-epa_1-2 class=reference>[2]</SUP></TD><TD align=right>1.0130</TD><TD align=right>98.72%</TD><TD align=right>112,500</TD><TD align=right>32.97</TD></TR><TR><TD>Gasoline (reformulated gasoline, ethanol)<SUP id=cite_ref-epa_1-3 class=reference>[2]</SUP></TD><TD align=right>1.0190</TD><TD align=right>98.14%</TD><TD align=right>111,836</TD><TD align=right>32.78</TD></TR><TR><TD>Gasoline (reformulated gasoline, ETBE)<SUP id=cite_ref-epa_1-4 class=reference>[2]</SUP></TD><TD align=right>1.0190</TD><TD align=right>98.14%</TD><TD align=right>111,811</TD><TD align=right>32.77</TD></TR><TR><TD>Gasoline (reformulated gasoline, MTBE)<SUP id=cite_ref-epa_1-5 class=reference>[2]</SUP></TD><TD align=right>1.0200</TD><TD align=right>98.04%</TD><TD align=right>111,745</TD><TD align=right>32.75</TD></TR><TR><TD>Gasoline (10% MBTE)<SUP id=cite_ref-nafa_2-0 class=reference>[3]</SUP></TD><TD align=right>1.0200</TD><TD align=right>98.04%</TD><TD align=right>112,000</TD><TD align=right>32.83</TD></TR><TR><TD>Gasoline (regular unleaded)<SUP id=cite_ref-about_3-0 class=reference>[4]</SUP></TD><TD align=right>1.0000</TD><TD align=right>100.00%</TD><TD align=right>114,100</TD><TD align=right>33.44</TD></TR><TR><TD>Diesel #2<SUP id=cite_ref-about_3-1 class=reference>[4]</SUP></TD><TD align=right>0.8800</TD><TD align=right>113.64%</TD><TD align=right>129,500</TD><TD align=right>37.95</TD></TR><TR><TD>Biodiesel (B100)<SUP id=cite_ref-about_3-2 class=reference>[4]</SUP></TD><TD align=right>0.9600</TD><TD align=right>104.17%</TD><TD align=right>118,300</TD><TD align=right>34.80</TD></TR><TR><TD>Bio Diesel (B20)<SUP id=cite_ref-about_3-3 class=reference>[4]</SUP></TD><TD align=right>0.9000</TD><TD align=right>111.11%</TD><TD align=right>127,250</TD><TD align=right>37.12</TD></TR><TR><TD>Liquid natural gas (LNG)<SUP id=cite_ref-about_3-4 class=reference>[4]</SUP></TD><TD align=right>1.5362</TD><TD align=right>65.10%</TD><TD align=right>75,000</TD><TD align=right>21.75</TD></TR><TR><TD>Liquefied petroleum gas (propane) (LPG)<SUP id=cite_ref-about_3-5 class=reference>[4]</SUP></TD><TD align=right>1.3500</TD><TD align=right>74.04%</TD><TD align=right>84,300</TD><TD align=right>24.75</TD></TR><TR><TD>Methanol fuel (M100)<SUP id=cite_ref-about_3-6 class=reference>[4]</SUP></TD><TD align=right>2.0100</TD><TD align=right>49.75%</TD><TD align=right>56,800</TD><TD align=right>16.62</TD></TR><TR><TD>Ethanol fuel (E100)<SUP id=cite_ref-about_3-7 class=reference>[4]</SUP></TD><TD align=right>1.5000</TD><TD align=right>66.67%</TD><TD align=right>76,100</TD><TD align=right>22.27</TD></TR><TR><TD>Ethanol (E85)<SUP id=cite_ref-about_3-8 class=reference>[4]</SUP></TD><TD align=right>1.3900</TD><TD align=right>71.94%</TD><TD align=right>81,800</TD><TD align=right>24.04</TD></TR><TR><TD>Jet fuel (naphtha)<SUP id=cite_ref-doe_4-0 class=reference>[5]</SUP></TD><TD align=right>0.9700</TD><TD align=right>103.09%</TD><TD align=right>118,700</TD><TD align=right>34.44</TD></TR><TR><TD>Jet fuel (kerosene)<SUP id=cite_ref-doe_4-1 class=reference>[5]</SUP></TD><TD align=right>0.9000</TD><TD align=right>111.11%</TD><TD align=right>128,100</TD><TD align=right>37.12</TD></TR></TBODY></TABLE>

 

Johbar can correct me if i'm wrong, but i think what he is referring to is the potential for better economy due to the increase in ignition timing.

the computer in the truck WILL increase the ignition timing if a higher octane fuel is used. particularly at low RPM where there is not much spark lead by nature, an increase in timing will provide for considerable opportunity for better combustion and more complete burn, thus better fuel economy.

most engines do not *require* high octane fuel, many do not have different spark maps to accomodate the higher octane fuel. Ecoboost does, so there is a potential for better performance and fuel economy if it is used. not saying it will or it wont, just that the potential is there.

Shotgunz, thanks for posting the chart!

one thing i found VERY interesting is the fact that E10 has almost the same energy content as gasoline+MTBE.