Telcomans Fuel experiment (in progress...)

[pfarmer]

I had lots more data from him to go off of, going back to 2006.

Do you have anyway of taking this data and possibly coming up with how it fits with temperature. It seems like maybe that information would be available.

Running 91 octane most of the time it seems that for me over the last few months that the difference between 30-40 degrees and 40-50 can show as much as a 10% difference.

In other words if I was running this same test over the last couple of months the temperature alone would seem to far exceed what is demonstrated by the difference in octane. But then I don't have anything I could compare to for the temperature difference and its affect on 87 octane use.

Telcomans data probably doesn't show this but maybe the average temperature along his route from previous years could be added to it.

One thing I notice is that the use of 93 octane seems to give more consistant mpg than the 87.

Perry

[Poyzinous]

Perry, temperature affects automatic trannys more than it does manual. Auto trannys need to warm up before they are at normal operation. You'll notice this sometime maybe: On a cold day, go out to drive on the highway, straight out of the driveway. set your cruise control at 60 and see what speed your engine is running at. maybe like 2700 rpm. After about 5 minutes, once the transmission is hot and lock up is in full effect and fluid is going through at its best operating temperature, you'll notice that the engine will be running at 2500 or so. When warmed up, the best temperature for a car is in the low 50's. When not warmed up, it will run better in the 70's. Manual transmission's since they are direct connect, dont have variances with internal speeds of the input and output shaft, like auto trannys, so there isnt a difference. understand? In the winter, I usually let my car run in the driveway for 3 minutes before i start driving, since i dont like sitting in the cold, but also i just like driving closer to operating temperatures, since I just feel like the car likes it more. I know i would hate it if someone woke me up and forced me to start jogging without stretching or eating or even fully waking up. I see that like my car.

[pfarmer]

perry, carbon footprint is slightly affected as well. Since higher octane fuel is more refined and (usually) has more beneficial additives, it combusts cleaner, and from the tailpipe, a car running premium has slightly lower oxides of nitrogen, a little less carbon monoxide, and just a teeny bit less CO2. Ask an emission inspector(for non OBD2 cars that have to run off a dyno). An environmentalist would want to use premium in his car if he wants to do the absolute best when it comes to exhaust gases.

Did you read what the total carbon footprint is that I referred to. Nox can be controlled by using a little less air in the combustion chamber but that will drive up the CO if reduce a little more than necessary. Chances are that the higher Nox with lower octanes is due to slightly higher combustion temperatures in the area where air is injected into the flame front. It would not be surpising to see a little less CO2 if you have less CO.

But there is more to the carbon footprint than the car itself. For the car the benefit is mainly in the reduced amount of fuel burned within a category. the rest is what it takes to produce the fuel itself. What it takes to purchase it needs to be considered as well.

For example the carbon footprint for agricultural fuels is consider low by many when burned, however its production is actually considered at this stage to have a very high carbon footprint. Using your example by itself would state that it has a low carbon footprint. Plastic bags are considered to have a long term negative effect largely due to disposal, however you can typically carry the same amount of bags from production line to the retail side of the tracks in as little as 1/6 as many trucks. So in reality 'paper or plastic' really becomes more complicated than simply looking at the waste disposal site.

I believe that the total carbon footprint should be examined before making the assumption that a reduction actually is present.

Perry

[pfarmer]

Perry, temperature affects automatic trannys more than it does manual. Auto trannys need to warm up before they are at normal operation. You'll notice this sometime maybe: On a cold day, go out to drive on the highway, straight out of the driveway. set your cruise control at 60 and see what speed your engine is running at. maybe like 2700 rpm. After about 5 minutes, once the transmission is hot and lock up is in full effect and fluid is going through at its best operating temperature, you'll notice that the engine will be running at 2500 or so. When warmed up, the best temperature for a car is in the low 50's. When not warmed up, it will run better in the 70's. Manual transmission's since they are direct connect, dont have variances with internal speeds of the input and output shaft, like auto trannys, so there isnt a difference. understand? In the winter, I usually let my car run in the driveway for 3 minutes before i start driving, since i dont like sitting in the cold, but also i just like driving closer to operating temperatures, since I just feel like the car likes it more. I know i would hate it if someone woke me up and forced me to start jogging without stretching or eating or even fully waking up. I see that like my car.

The one factor that comes into play for both types of transmissions is the engine. While the temperature of the oil, etc. of the engine may be close to the same regardless of ambient temperature within certain ranges, the temperature of combustion air will tend to follow the ambient curve without a mixing valve present such as those on older rigs or some other method of control.

I think Telcoman drives far enough that negative factors for transmission temperature probably doesn't rear its head up like it does for those that drive only a few miles.

I would like to test out the cruise control like you mentioned however that is a little difficult to do where I am located (unless on a trip). Typically when I would hit a patch of road where I could do that the car has been running for at least 15-20 minutes. I may have the opportunity however to try this out to see the numbers you mention which seem entirely logical.

I would think the effect due to ambient temperature on engine performance would vary greatly on location since there are other factors involved as well (humidity for one). I have a lot of experience with LM6000 gas turbines and in an industrial application you can see as much as a a 15% reduction between about 42 and 90 degree ambient. Other factors come into play above about 90 and less then 42. I would think one may see this as well in gas engines within a similar temperature range and see other issues come into play outside of it that would make it hard to follow.

It would be interesting if we had some ambient temp reference.

Perry

[pfarmer]

does anyone know the answer to this:If vegetarians eat veggies, what do humanitarians eat?

You are a prideful man?

Perry

[Poyzinous]

what? Stop trying to one up me. I just wanted to go a little deeper. you went very deep and thorough. are you an aerospace engineer or something? Or do you work in aeronautical fields? I can fly. I think. I never got my Private Pilots license. But I have a few dozen hours experience. Anyway, Reaction between turbines and engines is a little different. Compression and exhaust presssure being more dominant measures of power and efficiency as opposed to compression and combustion. Engines produce power in the measurement of kilowatts and horsepower, gas turbines produce megawatts and tons of thrust and you know the drill. engine efficiency is surprisingly stable when at operating conditions even when the difference in temperature is 30 degrees to 60 degrees, but once humidity becomes a factor, gas turbines have the operational advantage since I.C. motors have small displacements and are sensitive to single digit temperatures. My ears are starting to bleed. I'm thinking too much. Lets stop this now. We're going off track. Or at least I am.

[telcoman]

Do you have anyway of taking this data and possibly coming up with how it fits with temperature. It seems like maybe that information would be available.

Running 91 octane most of the time it seems that for me over the last few months that the difference between 30-40 degrees and 40-50 can show as much as a 10% difference.

In other words if I was running this same test over the last couple of months the temperature alone would seem to far exceed what is demonstrated by the difference in octane. But then I don't have anything I could compare to for the temperature difference and its affect on 87 octane use.

Telcomans data probably doesn't show this but maybe the average temperature along his route from previous years could be added to it.

One thing I notice is that the use of 93 octane seems to give more consistant mpg than the 87.

Perry

Perry

Here is more data on my trips from NJ to Florida that I believe clearly show how temperature effects MPG results.



My latest result on the first tankful of 91 Octane was 355 miles traveled. It took 14.784 gallons @ $2.02/gal to fillup for a MPG result of 24.01.

You will also notice that when the wife uses my G for short trips in Florida the MPG drops sharply compared to the MPG results obtained with highway driving.

Telcoman

[pfarmer]

what? Stop trying to one up me. I just wanted to go a little deeper. you went very deep and thorough. are you an aerospace engineer or something? Or do you work in aeronautical fields? I can fly. I think. I never got my Private Pilots license. But I have a few dozen hours experience. Anyway, Reaction between turbines and engines is a little different. Compression and exhaust presssure being more dominant measures of power and efficiency as opposed to compression and combustion. Engines produce power in the measurement of kilowatts and horsepower, gas turbines produce megawatts and tons of thrust and you know the drill. engine efficiency is surprisingly stable when at operating conditions even when the difference in temperature is 30 degrees to 60 degrees, but once humidity becomes a factor, gas turbines have the operational advantage since I.C. motors have small displacements and are sensitive to single digit temperatures. My ears are starting to bleed. I'm thinking too much. Lets stop this now. We're going off track. Or at least I am.

Power plant operator of coal, gas turbines, and hydros. In the case of Nox production my point was that of injection of air into the hottest part of the flame is a good way to raise Nox. Gas turbines as used in power plants are usually a Land/Marine derivative (hence LM in the name plate) and have various features not present on aero versions. For example I posted the temperature of 42. This will give you the highest amount of megawatts and falls as you go to about 90 or so. Below 42 you will typically use some for of combustion heating to eliminate ice from forming and damaging the turbine. That is why I state it is often hard to tell exactly what happens below 42 but my experience states it will increase in the megawatt range as long as you don't end up with icing.

The typical generator on a gas turbine in single cycle mode is driven through a shaft that passes through the engine which connects the fan to the generator. So in the case of the prime mover, the inlet fan is what is effectively the driver. There are various methods of ensuring the temperature in the combustion chamber one of which is injection of water into the inlet air stream in various stages. One side benefit of this injection in one area is power production goes up about 4 %. Gas recirculation schemes, etc. are some of the others. Now while the gas turbine is a different animal the concept of pollution control actually pertains to engines in general including internal combustion ones, in fact to boilers.

How the air temperature affects gas mileage in an IC engine is one that I am curious of. In the case of a car we modulate the coolant to try to maintain a certain temperature so over a range we can pretty much point to combustion air when we see changes in mph. With that air however comes humidity. In the case of the coolant, while the density probably should be a factor of temperature is there a different in discharge pressure based on cycling through the radiator or some recycling through the engine? This could change the parasitic loading of the water pump.

I would like to see Telcoman keep track of possibly temperature and also average mph since that is another huge factor that comes into play as well. Temperature should not be all that hard, in fact it and humidity probably could be had from easy to access local records. MPH could be had from the dashboard display on mine, don't know if available on an 06? I assume that to a certain extent as the temperature goes down below a certain value that road conditions drive the MPH down as well. This probably comes into play on the high end of the temperature range at some point too.

Perry


Modified by pfarmer at 3:37 PM 5/4/2009

[pfarmer]

Perry

Here is more data on my trips from NJ to Florida that I believe clearly show how temperature effects MPG results.

My latest result on the first tankful of 91 Octane was 355 miles traveled. It took 14.784 gallons @ $2.02/gal to fillup for a MPG result of 24.01.

You will also notice that when the wife uses my G for short trips in Florida the MPG drops sharply compared to the MPG results obtained with highway driving.

Telcoman

Thanks, I find it impressive on how well you keep this documented.

Perry

[telcoman]

Thanks, I find it impressive on how well you keep this documented.

Perry

I was throwing out stuff from the garage on Saturday and ran across my documentation from my 1988 Mazda 929 5 speed manual.

From a November 5th 2003 entry in my log I went 223 miles and filled up with 10.4 gallons @$1.48/gal for a MPG of 21.44

Overall my 06 G35 gets better mileage than my old 88 Mazda 929. I don't remember the size of the engine in the Mazda but the 298 HP G35 is much more efficient.

Telcoman

[Poyzinous]

the intake air temperature sensor monitors, uh, the intake air temperature. The ecu modulates fuel ratio and timing to current engine temperature and pressure that varies with humidity and temperature and therefore everything works the way it does. the variances change the MPG of the car because of the alterations in those respective areas. Whatever the case, victory is yours. oh, and coolant is always running. when cold, it helps warm up the motor. when hot, it helps keep it at one hundred seventy somehting degrees. Since that is a constant and not a variable, mpg is affected outside of this.

'lets go buy some eggs and boil them!'

[pfarmer]

and coolant is always running. when cold, it helps warm up the motor. when hot, it helps keep it at one hundred seventy somehting degrees. Since that is a constant and not a variable, mpg is affected outside of this.

My thought on the coolant was if there is a difference in pressure when it is bypassing the radiator. The temperature should be fairly constant and therefore no change in density, however the discharge pressure may well change. Being a centrifugal pump higher pressure on the discharge side due to restrictions would result in lower flows at a given pump rpm and lower pumping load to the engine.

Perry

[Poyzinous]

correct!

[joe603]

I think you guys are reading too much into the temp. thing...

First, it was Telco's wife who was driving. She may not have the self control of our MPG king. Next, it says "short trips" which can kill MPG numbers when the majority of the data is from highway miles. Finally, The next entry after Florida is the GA state line...notice the MPG shot up; most likely due to highway miles.

[pfarmer]

I think you guys are reading too much into the temp. thing...

First, it was Telco's wife who was driving. She may not have the self control of our MPG king. Next, it says "short trips" which can kill MPG numbers when the majority of the data is from highway miles. Finally, The next entry after Florida is the GA state line...notice the MPG shot up; most likely due to highway miles.

No I think that was not his point. That is you have his driving record in different months and in different locations. He mentioned his wife since those are the exceptions that needed an explanation. And further keep in mind that it appears that she was driving those short trips within Florida during a timer period encapsulated by other trips within the state.

As far as the temperature thing I believe that the parasitic loads may change somewhat. I don't know what the difference is in flow restrictions between the radiator bypass mode versus the radiator, maybe none so it doesn't come into play for water pump parasitic load. If you have an electric fan, that is a parasitic load that would change with temperature. Average miles per hour most likely change to a certain extent, and my experience is this will change your mpg a lot regardless of temperature. So while the temperature itself isn't the direct factor, the average mph (based on that temperature) you are driving is. Consider A/C as well when it comes to ambient temperature. Depending on your location many drivers simply turn it off. This has some effect, but depends on how often it would engage anyway. In my area A/C is in use at low temperatures for defrosters.

Lots of variables but we are fortunate in this set of samples in that we have a particular owner who keeps good records and drives under different conditons.

Perry


Modified by pfarmer at 10:46 AM 5/5/2009

[pfarmer]

correct!

What few understand is the difference of a centrifugal pump or fan. If you throttle the discharge your flow typically goes down and so does the load. The pump may become very hot to the point of pumping steam but it takes little to spin it. The same with a fan. If you take a centrifugal fan and close off the dischange the load will go down.

The point however is more than just this pump example, it is the entire set of parasitic loads. This could be cooling requirements changing, A/C use, and so on. Toss a little rain into a daily mix and the headlights will be flicked on by many. In certain areas colder weather equals rain and the lights will be in use, in other areas warmer weather will bring on the rain and the lights.

Perry

[telcoman]

No I think that was not his point. That is you have his driving record in different months and in different locations. He mentioned his wife since those are the exceptions that needed an explanation. And further keep in mind that it appears that she was driving those short trips within Florida during a timer period encapsulated by other trips within the state.

As far as the temperature thing I believe that the parasitic loads may change somewhat. I don't know what the difference is in flow restrictions between the radiator bypass mode versus the radiator, maybe none so it doesn't come into play for water pump parasitic load. If you have an electric fan, that is a parasitic load that would change with temperature. Average miles per hour most likely change to a certain extent, and my experience is this will change your mpg a lot regardless of temperature. So while the temperature itself isn't the direct factor, the average mph (based on that temperature) you are driving is. Consider A/C as well when it comes to ambient temperature. Depending on your location many drivers simply turn it off. This has some effect, but depends on how often it would engage anyway. In my area A/C is in use at low temperatures for defrosters.

Lots of variables but we are fortunate in this set of samples in that we have a particular owner who keeps good records and drives under different conditons.

Perry



Modified by pfarmer at 10:46 AM 5/5/2009

Perry

My point was to show the effect of short trips and how it reduces MPG as compared to highway driving.

Date Mileage miles Trav Gal Price MPG Total Paid Notes

4-Jun-07 29749 200 11.85 $3.07 16.87 $36.50

Wife using vehicle for local trips in Fl

9-Jun-07 29970 222 11.81 $3.06 18.79 $36.25

Wife using vehicle for local trips in Fl

10-Jun-07 30382 412 16.21 $2.89 25.41 $47.00 Ga

11-Jun-07 30787 405 15.42 $3.04 26.27 $47.00 NC

Near Va border

12-Jun-07 31200 413 15.13 $2.85 27.30 $43.25 EB NJ

While in Florida I do a lot of walking. The wife drives a mile or two to the fitness center and short trips for meals. This is clearly shown by the drop in MPG while we are in Florida. We fiiled up in the evening of 9 June 07 and left Florida the following morning reaching the Georgia border before filling up again. Notice how the MPG increased from 18.79 from the short trips while in Florida to 25.41 MPG between Florida and the Georgia state line where btw gas is much cheaper than in Florida.

It is clear to me and has been for many years that the use of regular 87 octane for long distance driving is fine. I believe this test with the three grades of gasoline will prove this out.

In my opinion if you run a G on cruise control for a few hours at 65 to 75 MPG anyone else should be able to obtain similar results

My daily 50 miles commute is usually on cruise control on the way in and rarely on the way home as there is much more traffic.

Telcoman

[telcoman]

Here are my latest results from my second tankful of premium 91 as I just filled up with the third tankful.

Date Mileage miles Trav Gal Price MPG Total Price7-May-09 87255 292 11.741 $2.04 24.87 $25.00

Notes Filled up with #3rd tankful Sunoco 91 Octane Temp between 50* & 70* F

Telcoman

[telcoman]

Here are my latest results from my second tankful of premium 91 as I just filled up with the third tankful.

Date Mileage miles Trav Gal Price MPG Total Price7-May-09 87255 292 11.741 $2.04 24.87 $25.00

Notes Filled up with #3rd tankful Sunoco 91 Octane Temp between 50* & 70* F

Telcoman

Today's results from 3rd fillup with 91 octane.

4th and last fillup with 91 octane today.

Final results in a few days. Next fillup is back to regular 87 Octane

Date Mileage miles Gal Price MPG Total Price Trav l

11May 09 87600 345 14.55 $2.19 23.71 $32.00

Telcoman

[telcoman]

Results from the fourth and final fillup of 91 Octane



Date Mileage Miles Traveled15-May-09 87905 305

Gallons Price per Gallon MPG Price to fillup11.913 $2.09 25.60 $25.01

Notes Back to Regular 87 Octane. MPG result is a little high due to a$$hole attendant refused to add another $.25 to $.50 after the pump clicked off

Telcoman

[telcoman]

FYI Telco...we're going to keep your findings seperate from Smockers thread for now. Once your done, we'll get everything all cleaned up.

Thanks!

I'm done!



Bottom line, the octane grade appears to have little or no effect on either my performance or MPG.

Temperature and humidity appear to have a greater influence.

This fact is apparent if you look at the results on trips to Florida. On trips made during the winter the MPG increases as the temperature rises while traveling south and decreases as temperature falls while heading north.

During this just concluded test with different grades of gasoline, the lower temperatures in early April resulted in a lower MPG. As temperatures rose into the 60's, 70's and 80's in May the MPG results rose even as I returned to using regular 87 octane.

Telcoman

[DAAN.]

...those trying to get a new engine by saying theirs was vandalized with sugar.

I just got my G, but isn't the fuel door opened only when doors are unlocked