infidel

Quote:

Doesn't float up and down like your fuel guage arm does. Please explain.

Sounds like you've never taken a fuel tank module apart before. The fuel pickup does float up and down on a track, the pickup hose looks just like a self coiling air hose. Fuel is always picked up near the top of the tank level.

Patrick Campbell

Land line is a great magazine, as is "Light and Medium Duty Truck" magazine, both are free!

Nobody pointed out that at any given point, Flying J has the CHEAPEST fuel. I've never seen this untrue. Sometimes other truck stops in the same area are close to it or even match it, but most truck stops are a few cents per gallon more, sometimes 5-7. Interesting....!

RickG

Check again . A couple of weeks ago I headed west on I-64 in KY and bought fuel at exit 94 for $2.15 . Further west at the Flying J it was $2.17 . The next day in Marion OH I bought fiuel at a convenience store and again down the road Flying J was higher . A penny or 2 won't save you money if the fuel has lower BTU's for whatever the reason .

kingofdodge7131

Im lookin for exact numbers here but for now im gonna shoot of my memory

Lets first take this to a place people might be able to see it. Take a piece of sheet metal, You have a 2x3 sheet that is 1 inch thick and weights 10 lbs ( im makin these numbers up) Now, you run it through a roller and now its 4x6 and 1/2 in thick. Now that same piece of metal still weights 10 lbs but is weaker none the less, a sheet that is 1/2 thick wont hold as much as one that is 1 inch, but it is still the same exact piece of metal


Now,, The standard for fuel temp delievery is 60F, I know this, and all though this is florida, They do state somewhere in this page i just found that they too will change the price of the gallon for the change in fuel deliever temp http://www.myflorida.com/st_contract...ifications.htm


Now,, Im shooting this off my hip, but i want to say every 30 F change will equate to 2.1% change is energy per gallon of fuel. For some reason 16% is popping in here too. So although you just pumped 1 gallon of fuel into your truck, you either paid for 98% of the energy or 84%. So lets pick 8% change,, Until i get smart and can find the information. Your fuel from flying j will only give you around 16.5 mpg if fuel at 60f gives you 18 mpg. hope that helps

Prodart440

"Now,, Im shooting this off my hip, but i want to say every 30 F change will equate to 2.1% change is energy per gallon of fuel. For some reason 16% is popping in here too. So although you just pumped 1 gallon of fuel into your truck, you either paid for 98% of the energy or 84%. So lets pick 8% change,, Until i get smart and can find the information. Your fuel from flying j will only give you around 16.5 mpg if fuel at 60f gives you 18 mpg. hope that helps"

So if this is true, once my fuel sits in 111 degree weather in AZ that I am not going to get the same mileage as someone in 85 degrees?? I don't think it makes that big of a difference. I am running flying J and I get between 16-17 mpg on mixed city and highway. If what is said above is true, I would be getting around 14 mpg.

Aaron

P Kennedy

Is it fuel temperature affecting fuel milage or chemical additives and base stocks that change the thermal efficiency, I do believe the latter two. Air temperature affects the efficiency far more as any body who travels after dark in the summer and high daytime temps will attest to. Does the fuel expand and become less dense yes but it also increases in volume which compensates for that each hot day you fuel in the morning and travel all day using that tank of fuel. If you find a source of clean fuel giving you good fuel milage use it, the name on the sign above the pumps is a personal preference as before stated some locations across the continent have no say in the origin of the fuel supplied. All refineries supply a spec product to each of it's customers within the confines of the base product and technology in the refinery itself. I will tell you from experience hauling the stuff that it depends on the stock available and the exchange programs each oil company has within each geographical region what truck loaded at what facility that day. The name on the side means nothing of either the truck or the loading/refining facility but the retail outlet managers prefer to have company trucks when possible to deliver at their stations for publicity purposes, where the fuel originated is irrelevant. PK

F. Flack

I've pulled the (fuel tank module) units out of my '99 and '00 to replace the pick-up tubes with solid/straight 1/2" tubes. What I found is the (stock) coiled pickup hose acts like a spring forcing the lower half of the cage to sit tight against the bottom of the tank. Therefore, as the tank bottom flexes up and down due to the weight of the fuel and road conditions, the bottom of the cage (with the fuel pickup tube attached to it) is always pushed tight against the bottom of the tank. When the fuel level drops below 1/4 tank, the inside of the lower half of the cage acts like a sump with a valve which closes off and holds fuel inside while turning or sudden stops. The fuel return is also plumbed inside the cage, so the stock pickup tube is always drawing the heated fuel before pulling the cooler fuel from outside the cage. No effect for driving in the heat, but warmed fuel is better for driving in sub-zero conditions.

One of the items I feel we are all missing is that once the engine is warmed up, the VP is running at a steady temp which heats and forces the fuel to be pushed out through the injectors at a steady temp. Therefore, the fuel temp inside the tank should have no effect unless it exceeds 195 degrees.

hammerjammer

my truck must be stupid,it gets about the same mileage ,where-ever i buy fuel and that includes flying J. Why would the large commercial fleets use flying j fuel if it was getting poor fuel mileage. these large commercial fleets track -fuel mileage on all power units.,even .1 mpg gain or drop would represent thousands of dollars

kingofdodge7131

Well for start it is a proven fact, if you like go to the department of energy they discuss it as well. As for your fuel being 111 degrees, your tanks are well below the ground. To the point where your 111 air temp wont have any effect on it. So the fuel you pump into your truck is at proper temp so you can get the energy out of it. Hence why you still get 16-17 mpg. Once its in the tank on your truck it can get as hot as it wants. Only problem is if you fill to the top then it spills over. But if its not to the top. youll have x amount of energy in your tank.

newriverSpecon

Thermal expansion is a fact. I don't know the rate that it affect #2 but I unknowingly did some experiments. There was also another post (I think on this board) from an individual that had similar issue to mine. There is even a TSB related to this. Remember the little caps that were left on the Roll over check valve? My issue is the check vale is stuck closed. Same as being capped(the related post problem as well). I could fill up or even sit for a duration and then drive for even 30 min and when I stopped I would hear a squeal. There was also a powerloss if I had a load. When I would crack the fill cap it would SUCK AIR IN. This means no matter what the heat expansion it was not enough to replace the volume of fuel burned. There is about 3 gal per hour burn on an empty truck. About 6 on a heavily loaded truck.

I think it is a quality issue and nothing to do with temp. As I stated in my other post I will try another Pilot on the other side of the freeway and see if I gain my 2 MPG.

Randy

newriverSpecon

I think he meant the tank on the trucks. Which sit only 18" above 170 degree asphalt. BTW our engines meter fuel by volume, not mass. Therefore the energy content going in the chamber will change. I don't think it is enough to be an issue, but. I read an article where they tested cold gas vs. warm gas (30 or 40 degree diff) in a Motorcross bike on a dyno. It made a .1 peak diff. but it did widen the peak substantially. But not enough for anyone but the top two or three riders to be able to take advantage of. Also the temp would increase so fast on the track it would only be an advantage it the first lap or two.

Randy

sweetwaterguy

Is Flying J heating their fuel to give them a competetive advantage? I am a skeptic and doubt any major supplier would do that--for the simple reason that if caught their business would be destroyed. There are all kinds of scenarios that would cause temperature varations, and we know clearly that colder means more dense and heavier, and hotter decreases density and therefore lighter. Perhaps fuel pumps to be totally accurate should sell fuel by weight and not volume.
Having said that, I don't want to use this forum to damage any company selling products without solid evidence they are cheating. It is an inappropriate use of this excellent forum.

RickG

The staff at Land Line magazine sent me more info on this . It's an adobe attachment and I don't know how to post it here but if anybody e-mails me at Rickgaskill@msn.com I'll forward the info to them .

Patrick Campbell

rick you could e-mail me patrick@cdevco.net and I can get it up on the web for people.

Patrick Campbell

I've personally never seen a Flying J more expensive than another station in the same relative location. This is from experience, 100K miles driving all over the USA. I'm sure it exists but doesn't seem to be common!!!

Another thing I might subconsciously take into consideration is that 99% of Flying J car/RV pumps are pay at the pump, which gives me an automatic 5% discount, which on $2.50 diesel is 12.5 cents, which knocks out the other station whose price might be 5 cents cheaper but has no pay at the pump. OK I'm just being confusing now...

Are you filling up at the CAR/RV section or truck section. Truck pumps are a good few cents higher than the car pumps.