Fuel Economy Analysis...

[N0DIH]

I am a Statistical Green Belt in training, and have been playing with my fuel economy in Minitab, a killer data analysis program. It is showing me some very interesting data points that I can make some theories on.

If you would want me to look at your data, please fill out as long history as you can, prefer no less than 10000 miles worth, indicating variables that occur like date, Ethanol fuel vs not, temps, winds, rain, snow, , lots of idling or not, additives, oil change weights, AC on/off, etc. See if your local gas station will tell you when they switch to the winter blend fuel too.

Fill out the info at fueleconomy.gov and go to the garage, and enter in all your data, and then export the csv spreadsheet and with Excel if you have it, indicate the dates or tanks that you make changes. Remember, 1 tank is statistically useless data. You need at lest 25 tanks of consistant data points in my book to make it worth making a theory on. 3 is bare minimum, but will only start to indicate a trend.

I will post my findings here shortly, it is pretty interesting to see what I have found on my data so far since Feb of this year. I have accumulated around 17K miles worth of data so far.

[90Brougham350]

I can't wait to see this data! How consistent are you finding things?

Brian

[N0DIH]

So far, what I am tracking is:
Date, miles, gallons, mpg, cost, cost per gallon, temperature, ethanol, octane (well, I don't change much, but I have run some 89 in when the price is the same, 90 is the midgrade there at Road Ranger in Rockford), AC on/off, weather (snow, rain, wind, etc), mechanical fan on/off (recent), fuel additive someone gave me, so I am trying it for 144 gallons, tire air pressure, Cold Air Induction vs First Base, 5W30 vs 15W40 (only 6K miles on 5W30, rest is 15W40), and then some general comments that were used to populate the fields.

I think I am fairly consistent, the variables are numerous in fuel economy testing. But I hope to come to some reasonable conclusions.

I might do 5W40 Rotella T synethic next, just to see what it shows. Then back to 15W40 Rotella T as a comparisson. 7K miles of each should show something.

If anyone has some ideas, let me know! But I also need the way or $$ to implement them!

[N0DIH]

One example, is the CAI vs the First Base.

I will be going over this data with my Black Belt to see if I am reading it correctly, but the initial look seems to indicate with some certainty that the CAI does have an 70% of the time a 0.5 to 0.75 average improvement over the stock first base.

In all my data, it is rare that the first base ever got any better mileage than the CAI (home brew one).

So if you are pondering this swap guys/girls! Go for it! I am NOT running a K&N, still a stock filter, I think a Fram or so. I am looking for a source of AC Delco air filters if someone can help me find one.

The values are:
19.03 mpg, std deviation are 1.132 for CAI, N=36 (samples)
18.79 mpg, std deviation is 1.552 for First Base, N=21

[N0DIH]

Another example is AC on vs AC off. Again, with a reasonable certainty, the AC off got better mileage to the tune of 1-1.5 mpg on many of the samples.

So, if you can, keep it off. It helps.

The mean values are

19.15 mpg AC off, a std deviation of 1.422, N=28
18.74 mph AC on, a std deviation of 1.146, N=29

[Stoneage_Caddy]

you outta see what we do with our home electric bills and such .....we have been watching a interesting trend with our A/C useage , it goes up , but there is no real warming treands on the graph side (we have a home weather station that transmits data to the PC), we are thinking we are running low on refigerant or there is a dirty coil .....

why am i saying "we" its really "dad" i got no clue , i just ask alot of questions ...

as far as fuel data , dad runs a chart thing ont he computer and imputs all fuel and vehicle related recripts and data iinto it , we saw a dive in gas milage (albeit minute) with the new tranny in our 00 silverado over the old one ....on average its around a 1 mpg loss after the new one was installed

I started to do that witht he cadillac ....but my fuel useage and parts installations are so damned often it became waay to much work ....i watch the cars AVG mpg and instant mpg over my commute everyday , when i see either fluctuate (i commute the same ammount every day) i start looking for the issue ....normally i find a low tire or something like that

[N0DIH]

Excel is as a model rocket from a hobby store as compared to Minitab is as the Enterprise is when it comes to statistical analysis. Excel is ok, does some stuff graphs, charts, etc, but Minitab is so awesome it is amazing. Most people would be lucky to us 10% of the capabilities of Minitab. I am no exception! It is overwhelmning how much you can do. Let alone understand.

I am glad to hear your dad does look at the data, it really helps refine us wasting $$ for no reason. Today was high 80's with moderate humidity and my friends AC ran all day long. He suspects low freon too. It shows up. The more data points you can get, like go out and read the meter hourly and track the inside temp each hour, and the outside temp each hour, etc, you will see neat things show up.

I don't know if there is any trial version of Minitab, but go to Minitab.com and look. I can try to help if you need help running it. It is not easy to learn, not intuitive at all.

[N0DIH]

Ok, this is a very very small (meaning it doesn't mean much yet) sample set of the mechanical fan data. I will update this as I get more data under my tires....

But if you look at the plot of normality, you can see the projections of where the lack of mechanical fan may be headed. Honestly, until I see 20+ samples here (20 fillups and mpg calculations) I don't trust a whole lot. But it does appear to be promising.

The data so far is:
_______________Mean___Std Deviation_____Sample Size_____P Value
With Mech Fan: 18.88 mpg__1.234____________56__________0.092
W/O Mech Fan: 20.38 mph__2.399____________2___________0.227

The Std Deviation is: A statistic used as a measure of the dispersion or variation in a distribution, equal to the square root of the arithmetic mean of the squares of the deviations from the arithmetic mean.

Or in english, how widespread the data is. As you can see, the normal with fan is reasonably tight, but the mech fan delete is not, as there is only 2 samples. The P-Value is telling us that the data isn't great. If you want to read up on all this, take a look here: http://main.isixsigma.com/forum/show...essageID=50176

[N0DIH]

Here is one a lot of people may pay some interest, oil weight. 5W30 vs 15W40.

Mean__StDev__N___AD_____P_____Comments
19.01__1.678__18__0.490___0.193_5W30
18.90__1.083__40__0.688___0.067_15W40

So yes, 15W40 does cost you a little tiny bit in the fuel economy catagory.

But as the P Value shows, as well as the Std Dev, the data is much more consistent with the 15W40. Where the 5W30 is not. Why? Don't know, the car was new to me then, had fresh 5W30 in it, and I was still playing some too. Had some winter weather to deal with as well.

I say not enough data to draw a valid conclusion, although the data does show a trend towards it. See the graph and you will understand why.

[N0DIH]

Now, we come to reformulated gasoline. This one everyone has claims each way, and the politicians do too. But they have motives of "jobs in my state" that tells us that they don't tell us the whole truth. And Valen said half a truth is worse than a lie....

So, with ethanol fuel (most stations in northern Ill have it) and most stations in SE WI (not Milwuakee area) don't. So I get a nice selection when I need it.

Mean___StDev___N____AD______P______Comments
19.08___1.312___34___0.603____0.108__W/O Ethanol
18.73___1.237___24___0.608____0.101__With Ethanol

Data is very consistant. Look at the graph, and lat a fat pencil on the data points. Are they all in it? Yes? Good, data is "Normal", if not, data is not normal. P values above 0.050 are Normal, under, are not, and data is not very trustworthy.

So you can see an average (mean) of around 0.35 mpg by NOT running ethanol "enriched" fuel. Yeah, it messes things up. But FWIW, it isn't as bad as it could be.

You see some of the data points much higher in mpg, that is a short highway trip. I will have to sort by that data and possibly take it out of the sample, as it is a normal daily drive inconsistency.

[BluEyes]

Well, Ethanol has less chemical energy per gallon than gasoline, so of course it reduces MPG - does anyone claim it increases MPG? It is cleaner burning, although that doesn't affect your wallet nearly as directly.

The mech fan is very nice to see such a gain. Was your mech fan a solid/flex fan, or a clutch fan?

Have you ever done a comparison of 5W30 vs 10W30? 15W40 is a bit heavy for our Caddy engines I think (unless you have a diesel Cad!). Although the new 5W40 synthetics are tempting for year round use in places like where I live - over 100 in the summer, and cold in the winter!

[N0DIH]

Well Sal pushed the 15W40 pretty strong, with good reason, I feel. I might mess with it sometime. He insists to use 15W40 year round unless you see below -10F for extended periods. Being my engine is 165K miles, and it still has a distributor gear (runs the oil pump), might as well give it as much anti wear as I can.

The oil is still a 40 weight hot, and 15 weight cold (what temp cold, I wish I knew...) So a 5W30 vs 10W30 at hot temp should be identical.

The fan is the factory 7 blade clutch fan with a thermal/rpm clutch on it. It is not as tight as many people describe (loud roar when cold), or maybe those are failing clutches or ones replaced with a rpm only clutch. The thermal ones nearly fully disengage at below the lockup temp. Being the LT1 runs pretty cool and stable at temp now, unless you see extended traffic at 100F+, or towing (which is what it is on there for), I am starting think it won't have a huge impact on the fuel economy. But it does seem to have some so far, note that I like 25 samples before I declare a real statisic. So I have a lot of tanks of fuel to go! I should be able to make a determination around Christmas or just after.... I do have a medium distance trip coming up in October, so I hope to see what real all out highway will do on this car. All my highway trips have been 100-150 miles so far, so too short to be worthy.

[N0DIH]

For those of you interested in seeing my actual ongoing project, Minitab does have a 30 day demo at http://minitab.com/products/minitab/14/demo/.

PM me and I will see if I can figure out how to send my project file.

[N0DIH]

Another test I am running is "Freedom Fuel Additive". This apparently is an Amway product (note the bottle does not say Amway anywhere on it). The bottle treats 144 gallons, (1 oz per 12 gallons). I was given the bottle from a friend, so I figured I would test the claims that is WILL improve fuel economy 8 to 12%. IF the claims are true, this would still save me $1.50 per tank despite the $15.00 cost per bottle. I appologize to anyone, but any fuel additives that claim such high fuel economy numbers I don't honestly believe, call it my St. Louis upbringing, but Show Me....

So, so far, with only 8 tanks with it (some smaller, 110 to 220 mile tanks as well). Am I mixing testing? Yes, but that is some of the beauty of statistical analysis, you can see it if the test is set up properly. Call it a DOE, or Design of Experiements.

The numbers are:
Mean StDev N AD P
18.93 1.261 50 0.690 0.067
18.96 1.505 8 0.397 0.279

We are tighter in deviation with my long term average (which tells us that I am fairly consistent in my driving style and my route). The FFA isn't too bad for StdDev ("=STDEV" in Excel if anyone wants to use this function on thier own), reasonably tight still.

So you can see my "N", my sample size, is rather small in comparison to the non FFA additive. But, it also shows my long term fuel average since I have bought the car is 18.93 mpg. With FFA additive, it is up to 18.96. I call that nothing. Very far from 8%. The typical answer from the Amway salesperson insists that you have to keep using it more than one bottle. I say 2700 miles is plenty to see some change for the better or worse. My theory is the claims are based on an assumption that your engine is in poor shape to start with. Mine isn't. So the claims I feel should have a * by it stating that. Else I feel it is a misleading claim. It MAY be a valid claim, but I don't personally feel it is for EVERYBODY, which is how the material presented makes it seem.

So, as with all products, your results may vary, use at your own risk, invest nothing that you cannot afford to lose, etc.

Some links reffering to the stuff:
http://www.utahgasprices.com/Forum_M...age_no=1&FAV=N
http://www.polarmolecular.com/testing.html
http://www.cadillacforums.com/forums...c/41308-1.html
http://impalassforum.com/cgi-bin/ult...y;f=9;t=001302

They all swear by it, but I am not seeing anywhere close to these "claims".

I will post my updated results when I have used the whole bottle (for 144 gallons). Whether or not I continue to use it for additional data points as per the Amway sales pitch, I don't know just yet....

[BluEyes]

Originally Posted by N0DIH

Well Sal pushed the 15W40 pretty strong, with good reason, I feel. I might mess with it sometime. He insists to use 15W40 year round unless you see below -10F for extended periods. Being my engine is 165K miles, and it still has a distributor gear (runs the oil pump), might as well give it as much anti wear as I can.

It's the cold start lubrication I don't like there. 15W is really thick on those cold mornings and doesn't flow really well. Being as the vast majority of engine wear is right at startup, that 15W is going to take awhile to get around everywhere.
On another car that I have run 5W30, 10W30, and 20W50 in, I definately saw the oil pressure rise faster with the lighter oils. The oil pressure sender on this car is first thing in the oil path after the filter, so I hate to think how slow pressure was to build further down the line...

The oil is still a 40 weight hot, and 15 weight cold (what temp cold, I wish I knew...) So a 5W30 vs 10W30 at hot temp should be identical.

Hot temp is 212*F. Cold is, I think, 0*F. Or it is 32*F, I forget...

Theoretically, a 5W30 and a 10W30 should be identical at temp, BUT the SAE weights are a range. As long as the oil tested falls in the 30 weight range at the testing temp, it gets the 30 designation. If you get the viscosity figures from the oil companies, a 5W30 is usually a lighter oil at temp than a 10W30 from the same product line.

The fan is the factory 7 blade clutch fan with a thermal/rpm clutch on it.

Cool, I'll have to try electric on my '70 then. I have the factory solid/flex fan - no clutch at all, so the gains should be even more. All the older BB cads I've seen have been this way, but thesedays they have some pretty strong electric fans on the market. Probably run dual fans for that big radiator.