My “Real Gas” Experiment

[HiTech]

Originally Posted by BigH

Are you suggesting timing and torque converter lock-up can account for the 26% increase in mpg?

Under some specific conditions, yes, I am, especially when you add in holding top gear instead of downshifting. I have seen huge differences on the same hilly route with various Ford powertrains, between holding top gear and 96% torque converter, and one gear lower but only 80% lockup. I could not believe it at first. The biggest factor when I am driving is cruise control. Cruise seems to sacrifice throttle tip-in responsiveness for holding a gear with a locked converter. Under the right conditions, the exact same grade at the same speed driving manually runs a gear lower with an open torque converter. You can watch the PCM work hard to avoid unlocking and downshifting by throwing massive timing at the hill in certain situations.

[BigH]

Originally Posted by HiTech

Under some specific conditions, yes, I am, especially when you add in holding top gear instead of downshifting. I have seen huge differences on the same hilly route with various Ford powertrains, between holding top gear and 96% torque converter, and one gear lower but only 80% lockup. I could not believe it at first. The biggest factor when I am driving is cruise control. Cruise seems to sacrifice throttle tip-in responsiveness for holding a gear with a locked converter. Under the right conditions, the exact same grade at the same speed driving manually runs a gear lower with an open torque converter. You can watch the PCM work hard to avoid unlocking and downshifting by throwing massive timing at the hill in certain situations.

What's huge? You saw a 26% increase?

I have the same motor in my truck as the op. I have ran 85oct/87/89/91/93/E85 and pure gas in my truck. I've done this in the eastern mountains and the flat lands. Tested it towing and empty. I have never seen any % change of more than single digit percentages without strong tail winds or slower speeds. Except the e85 which had cost deficit high enough to rule out any other attempts.

So if your 'under some conditions' includes a strong tail wind as I suggested in my first post (or slower speeds) then I could see it...otherwise I'm certain my 6.0 is not capable of anywhere near that increase for similar conditions with any pump gas % or octane. If you do some research on this motor you would find my results are typical.

[MR.M]

Originally Posted by BigH

I absolutely did take the octane difference into account and left it out on purpose. This octane difference is a variable and impossible to measure except with the motor doing the test. I simply did some math to show an extreme % of difference has to be accounted for.

And, what you said was this:


Considering you quoted me and given your vague text one could easily interpret you meant an even greater % than what I was talking about. Because of that (for clarification on your belief) I asked if you are suggesting his truck, which was designed to run on 87, had a 26% increase in mpg due to the +2 octane increase?

Seemed reasonable to me.

I simply state there are different variables to consider . I'm not into nit picking what someone claims as not being possible. weather condition could factor in was it a cool moist day ? hot dry day . etc . i don't claim anyone is right or wrong and none of this is worth getting worked up about . there is more to mpg then just what gas you use .

[TheWolfPaq82]

My last three trucks (Gas) Had a GMC diesel for a couple years, but they all performed way better in MPG on the interstate / Hwy with non-ethano. 2004 F-150 V8, 2012 Chevy crew 1500 V8, 2019 Chevy Colorado V6. The current...2019 Colorado gets about 3-4 mpg more on non-ethanol than 10% when running to cabin. 100 miles exactly....door to door. Done this at least 5 time now, with the same result each time.

[Jay2504]

Nomad297, thank you very much for running this test. Because as you state, this is a run that you make often, can I ask if you will please run the test again? Between the test that you ran,and Hi Techs comments, you may really be on to something here. I have just bought a 2020 2500hd gas and am REAL curious about this! One more question, what brand of gas did you use?
Hi Tech, do you have any experience with Chevy powertrains? I would think that the ECM strategy would be similar, but would like to know for sure? Thanks,Jay

[HiTech]

Originally Posted by Jay2504

Nomad297, thank you very much for running this test. Because as you state, this is a run that you make often, can I ask if you will please run the test again? Between the test that you ran,and Hi Techs comments, you may really be on to something here. I have just bought a 2020 2500hd gas and am REAL curious about this! One more question, what brand of gas did you use?
Hi Tech, do you have any experience with Chevy powertrains? I would think that the ECM strategy would be similar, but would like to know for sure? Thanks,Jay

My experience with GM powertrains is 10 years out of date (other than one VVT push rod engine vehicle I still own). Loved my V series cars! I talked to a GM Chief Engineer in 2004 or so who told me all significant powertrain updates in the US going forward would take full advantage of whatever retail pump octane was available. Do not remember any PCM strategy nor calibration details beyond that (other than that the supercharged 3800 powertrain came from the factory with the correct calibration to use a smaller 3.4” pulley with no changed required other than the hardware).

[HiTech]

Originally Posted by BigH

What's huge? You saw a 26% increase?

I have the same motor in my truck as the op. I have ran 85oct/87/89/91/93/E85 and pure gas in my truck. I've done this in the eastern mountains and the flat lands. Tested it towing and empty. I have never seen any % change of more than single digit percentages without strong tail winds or slower speeds. Except the e85 which had cost deficit high enough to rule out any other attempts.

So if your 'under some conditions' includes a strong tail wind as I suggested in my first post (or slower speeds) then I could see it...otherwise I'm certain my 6.0 is not capable of anywhere near that increase for similar conditions with any pump gas % or octane. If you do some research on this motor you would find my results are typical.

Please never, ever, ever run 85 octane in an engine recommending 87. There is significant risk of dangerous preignition.

I did buy a 2001 E450 v10 that I drove for 10 years. My recollection is I got about 9.5 MPG long term not towing, no matter what the conditions. However, that was running a 20 year old PCM, strategy and calibration. These are periodically updated with significant new algorithms and technology (faster processors with much better knock detection, for example). I believe the V10 had one hardware update sometime since then as well, before Godzilla replaced them.

One of the byproducts of faster PCMs is the ability to be much more aggressive on adding a bunch of timing, say to climb a hill, and then let the heads cool off on the following downhill run. Modern Ford HP and torque numbers are based on top tier premium fuel, a recent change. The reason is that premium gives you more power and torque on modern Ford engines.

[BigH]

Originally Posted by HiTech

Please never, ever, ever run 85 octane in an engine recommending 87. There is significant risk of dangerous preignition.

85 octane was ran at high altitudes...

[BehindBars]

Originally Posted by HiTech

Please never, ever, ever run 85 octane in an engine recommending 87. There is significant risk of dangerous preignition.

Never say never, ever, ever. 85 octane is sometimes appropriate for some engines at high altitudes.

[TitanMike]

Originally Posted by HiTech

Please never, ever, ever run 85 octane in an engine recommending 87. There is significant risk of dangerous preignition.

At high altitudes it's very acceptable.

The issue might be if you fill up in Denver, along with any spare fuel tanks, then drive to a lower altitude where the oxygen content of the ambient air is greater.

I lived in Colorado where all "Regular" was 85 octane. 10 years on 4 different vehicles, one driven close to 3,000 miles per month, and NO issues whatever. All with EFI.

[Matthuck88]

You will actually make more power with e85 than regular gasoline, provided your engine can use e85. You will burn more of the alcohol than you would gasoline though.

[Jay2504]

Thanks Hi Tech, for the quick response. One of the things I did notice when using a very basic code reader while driving our old TV, was that when driving it up a hill in 5th gear with the cruise control not engaged, was that even though my foot moved very little, the throttle would open 85% before it would downshift to 4th gear. I did not look at timing to see if it advanced any when climbing the hill. I would think that it would retard or at least leave it the same, but my thinking goes back to the distributor days with a vacuum advance. Jay

[TitanMike]

Originally Posted by nomad297

Could there be any other factors involved, because I really don’t think I had a strong north wind pushing me down I-95 south, and I definitely wasn’t driving any more conservatively than usual.

Bruce

One of those factors could be the actual changes in altitude over the entire trip. Not so much due to air density but whether the entire trip was mostly uphill or mostly down hill.

Most mileage calculations for comparison purposes are only valid if the trip is repeated in the reverse direction.

An example is when I make a trip from my home to the eastern side of my State. From West to East involves climbing from near sea level to a pass just under 3,000 feet. The East side (where I camp) is ~2,000 feet.

My fuel mileage going East is 20% less than when I return home. If I were evaluating two different fuels I'd have to do it over both directions or the "downhill" part of the trip would certainly skew the calc's.

For calculations I just look at my Scan Gauge and it's right there without having to do any math or make sure I fill the tank exactly the same.

[BigH]

Originally Posted by HiTech

Please never, ever, ever run 85 octane in an engine recommending 87. There is significant risk of dangerous preignition.

I did buy a 2001 E450 v10 that I drove for 10 years. My recollection is I got about 9.5 MPG long term not towing, no matter what the conditions. However, that was running a 20 year old PCM, strategy and calibration. These are periodically updated with significant new algorithms and technology (faster processors with much better knock detection, for example). I believe the V10 had one hardware update sometime since then as well, before Godzilla replaced them.

One of the byproducts of faster PCMs is the ability to be much more aggressive on adding a bunch of timing, say to climb a hill, and then let the heads cool off on the following downhill run. Modern Ford HP and torque numbers are based on top tier premium fuel, a recent change. The reason is that premium gives you more power and torque on modern Ford engines.

I don't see how this pertains to my questions or backs your assertations...

What is the mpg differences that you called huge?
Did you see a 26% increase?

[HiTech]

Originally Posted by BigH

I don't see how this pertains to my questions or backs your assertations...

What is the mpg differences that you called huge?
Did you see a 26% increase?

On individual trips, yes.

I consider this a friendly discussion where a number of us are sharing experiences. I am not trying in any way to “back my assertions” or convince you of anything whatsoever.

[HiTech]

Originally Posted by Matthuck88

You will actually make more power with e85 than regular gasoline, provided your engine can use e85. You will burn more of the alcohol than you would gasoline though.

Quite right. Also the blend octane of E85 is over 100 octane, and the cooling effect on the combustion chamber of burning it is significant.

[BigH]

Originally Posted by HiTech

On individual trips, yes.

I consider this a friendly discussion where a number of us are sharing experiences. I am not trying in any way to “back my assertions” or convince you of anything whatsoever.

It is a friendly discussion but when one makes big claims and then offers this:

Originally Posted by HiTech

My recollection is I got about 9.5 MPG long term not towing, no matter what the conditions. However, that was running a 20 year old PCM, strategy and calibration.

...it actually is the opposite of what you were saying. I thought the discussion was about figuring out how Nomad recorded such a high mpg gain.

[HiTech]

[QUOTE=BigH;2474444]It is a friendly discussion but when one makes big claims and then offers this:


...it actually is the opposite of what you were saying. I thought the discussion was about figuring out how Nomad recorded such a high mpg gain.


This was also my experience. I am not trying to convince anyone, especially you, of anything. I am not filtering data that only supports some claim of mine. That would be rather one sided and unethical, unless I were in a formal debate, which I am not. I am sharing pertinent experiences. Why is that hard to understand?

Making a case, and ignoring good data that goes the other way is puerile. I am advancing a rational discussion, considering all sides.

This started with a member here stating and interesting finding he had one one trip. My assumption is that he made that statement in good faith. It is an interesting topic worth exploring.

[HiTech]

Originally Posted by TitanMike

At high altitudes it's very acceptable.

The issue might be if you fill up in Denver, along with any spare fuel tanks, then drive to a lower altitude where the oxygen content of the ambient air is greater.

I lived in Colorado where all "Regular" was 85 octane. 10 years on 4 different vehicles, one driven close to 3,000 miles per month, and NO issues whatever. All with EFI.

That is from the days of carbureted vehicles.

Please do not run 85 octane in your v10.

Page 76:

“E161513
We recommend regular unleaded gasoline with a pump (R+M)/2 octane rating of 87. Some fuel stations offer fuels posted as regular unleaded gasoline with an octane rating below 87, particularly in high altitude areas. We do not recommend fuels with an octane rating below 87.”

Page 76:

https://www.fordservicecontent.com/F...US_05_2018.pdf

[HiTech]

Originally Posted by Jay2504

Thanks Hi Tech, for the quick response. One of the things I did notice when using a very basic code reader while driving our old TV, was that when driving it up a hill in 5th gear with the cruise control not engaged, was that even though my foot moved very little, the throttle would open 85% before it would downshift to 4th gear. I did not look at timing to see if it advanced any when climbing the hill. I would think that it would retard or at least leave it the same, but my thinking goes back to the distributor days with a vacuum advance. Jay

Yes these days there is an additional component to timing. Octane Adjust Ratio is a variable the PCM uses to track the actual quality of fuel you are burning. When you have excess knock it immediately downgrades OAR. When you have a sustained period of low knock, it improves OAR. OAR of better than zero results in up to an extra 6 degrees of timing on top of the normal timing adjustments you are used to. OAR of worse than zero can result in a 4-6 degree reduction in timing due to excess knock detected, such as with low octane fuel. You can read this from the PCM in a PID that displays the current knock reduction timing adjust. Negative knock reduction is timing increase.