Fuel Economy Series 60 Fuel Mileage battle.....

mndriver

curmudgeon extraordinare
Supporter
I can pull those same numbers too without the additive running that light also as it is.
 

mndriver

curmudgeon extraordinare
Supporter
7.1-7.2 with 44k loads with stop and go driving every 15 miles.

Been doing local stuff lately
 

mndriver

curmudgeon extraordinare
Supporter
So digging out past data on the truck. I pulled the dyno reports from Dec 2012 when I had the truck tuned.

Specifically, I was looking for data on the Baro sensor if it was available. It was.

on the "Pre" it showed a pressure or 14.05 PSI. On the Post, it showed a pressure of 96.5Kpa or 14.00 PSI. What's interesting is that the elevation of the location this is at should have been around 14.3 to 14.4 PSI. For 14 PSI, that's an elevation of almost 1500 feet. A difference of 1000 feet what the truck is reading vs where it really is.

What I am REALLY looking forward to is that Wednesday next week, I have dyno time scheduled on the very same dyno from Dec 2012.

We'll see how all this work has paid off now with hard numbers.
 

8978

** Commie Express **
Supporter
I would have to look at the Data Sheet for the sensor being used. Truck manufacturers don't build their own sensors. They may have the plastic enclosure built but the sensor probably comes from a supplier like DigiKey.

The problem with barometric sensors is that they are calibrated at sea level. When there is a high pressure it will give you a false reading. There is no way to adjust on the fly. If there's a low pressure because of an approaching storm your engine is going to think it's at a higher altitude. I don't think they care too much about this problem. If it were that serious they would use a GPS chip which will show very accurate elevation.

But, on the flip side they may actually be more concerned about the real barometric pressure and not the altitude. Now that I think about it that would make more sense.

I think you correlating readings with elevation may be a mistake in this case unless your reading the bench results when your local pressure is at 28.92 (sea level).
 

mndriver

curmudgeon extraordinare
Supporter
I would have to look at the Data Sheet for the sensor being used. Truck manufacturers don't build their own sensors. They may have the plastic enclosure built but the sensor probably comes from a supplier like DigiKey.

The problem with barometric sensors is that they are calibrated at sea level. When there is a high pressure it will give you a false reading. There is no way to adjust on the fly. If there's a low pressure because of an approaching storm your engine is going to think it's at a higher altitude. I don't think they care too much about this problem. If it were that serious they would use a GPS chip which will show very accurate elevation.

But, on the flip side they may actually be more concerned about the real barometric pressure and not the altitude. Now that I think about it that would make more sense.

I think you correlating readings with elevation may be a mistake in this case unless your reading the bench results when your local pressure is at 28.92 (sea level).

I'll let you know come Wednesday. It's going up on the same dyno I ran it on in Dec 2012. I'll see how it compares to it then.

But I understand where you are coming from on this.
 

mndriver

curmudgeon extraordinare
Supporter
Yop, the nerd in me came out this weekend.....
http://www.mathsisfun.com/data/standard-deviation.html

The "simple" version of it is, how much can you expect the value to go from the mean. If you have an average of 6.2 and a standard deviation of .61, you can expect the fuel mileage to be 5.6 to about 6.8 MPG and that would be reasonable and expected.

I went back over the last 2 years since I bought my truck. Up to April of this year, my Standard Deviation has been about 1.57. My average was for 2012 was 6.7 with a SD of 1.77. In 2013, it was 6.25 and SD of 1.57. I was having issues with CAC, overhead, leaking exhaust, cracked exhaust.

For most of 2014, after the most before I replaced my baro sensor, I was seeing a 6.1 mpg and a SD of .91. And my mileages were for the most part from 5.2 to 6.8.

AFTER the baro sensor went in, My mileage has jumped to 7.1 and my SD has dropped to .61. And that's what I needed to see. Because it tells me that my engine is actually DOING what it's supposed to be doing controls-wise.

Standard deviation is one way of looking at your averages over time and seeing if SOMETHING changed. Good, bad or indifferent. In this case, it's telling me the computer is NOW finally doing what it's supposed to with all of the inputs to control the output and do it efficiently.

Without the engine working correctly, I can do all I want to change my trailer, tires, oils etc. It's pointless until the powerplant is working RIGHT.
 

8978

** Commie Express **
Supporter
Just a side note. I was pulled over at the top of the Eisenhower tunnel in Colorado. It was a very stormy night during the summer and very low pressure I'm assuming. I was going to stay there and go back to bed. Only took about 15 minutes before I could feel the effects of altitude sickness and had to continue down.

I figured between the low pressure from the storm and it being night I was maybe above 13,000 feet.
 

mndriver

curmudgeon extraordinare
Supporter
well I never got my truck onto the dyno like I wanted to this week. However, based on miles ran and fuel purchased, I am averaging 7.5 so far for the month of July. Light loads though. My heaviest so far has been 30,000 compared to the 40-44K I have been pulling.

Been running at 1375 RPM averaging 66 mph.

I found my old numbers from when I had the ECM tuned in Dec 2012. Here's the power charts from it. I try to keep the engine RPM between 1300-1700. Flat land cruise between 1300 to 1375. The bigger the rolling hills I'll push it up to 1450-1500 and in the mountains I'll grab a lower gear and maintain 1550-1700.
dyno.jpg

For the other nerds out there who use excel, I use the data analysis add-in to give me this for what my fuel mileage is. I have weekly averages for all of my fuel mileages and run that weekly average in the add-in.
stats.jpg

ETA:
Here are the gains that I saw from my tune. I am waiting to get back onto the dyno to see if there are any other gains.
gains.jpg
 
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mndriver

curmudgeon extraordinare
Supporter
Playing with month end numbers. I also have to give a regular report of this to where I got my SBA loans.

Here's how my fuel cost is impacting my Revenue.

Total truck fuel also includes reefer and additives...
fuelpercent.jpg

January I idled a lot when in MN. It was dang cold this winter. July I have been hauling ice cream.
 

Mike

Well-Known Member
Staff member
That's a significant drop, and looks to be a significant increase in profit.
 

Mike

Well-Known Member
Staff member
I am planning on getting them for the tractor when I get my new truck. I would like to run them on the trailer, but pulling different trailers all the time, I would be sure to leave them somewhere within the first month probably.
 

Hammer166

Instigateur №166™
~snip

But, on the flip side they may actually be more concerned about the real barometric pressure and not the altitude. Now that I think about it that would make more sense.

I think you correlating readings with elevation may be a mistake in this case unless your reading the bench results when your local pressure is at 28.92 (sea level).
That is indeed the key. Density altitude is far more important than actual altitude, as the amount of fuel the engine needs to inject depends on the density of the intake charge.
 

mndriver

curmudgeon extraordinare
Supporter
That is indeed the key. Density altitude is far more important than actual altitude, as the amount of fuel the engine needs to inject depends on the density of the intake charge.

A MAF or MASS is typically used to determine Mass flow or density. They will run a current through a grid or across a resistor and the rate it cools it tells the mass.
 
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