i went to arizona for a month wile i was there i was getting around 3 MPG better fuel milage than in cali, difrences, cali 500 feet above sea level arizona 4000 feet above sea level at the location i was at, outside air temp cali 75-80 degrees AZ 90-105 degrees, humidity cali some AZ none, drove the same city highway in both cali and AZ, the fuel difrences i dont know but i used chevron fuel in both states, any explanation?

 

Less oxygen in the air means less fuel is required. Cooler air is denser and and the higher the altitude the less oxygen in the air. The gas is also most likely a different blend taking into consideration the temp and altitude differences.

 

Hiya BT !

At 4,000 feet elevation, yer truk wuz lighter, bein' farther away from the centre of the Earth, and all.

Could been different local formulations - or the fact that octane demands go down as elevation increases, so your BSFC went down - ( inverse relationship: BSFC = lb/Hp-hr) - a little for the same (91) octane, hence the small mileage increase.

How ya been, anyway? Jeez - what a nomad you are !

Cheers!
Grog

 

i am good and yourself? i like to travel and do alot of it plus being in the Marines they send me all over, being in the hotter climate AZ i thought that my MPG would go down due to the HP TRQ loss of the higher ambeint air temp, but i just thought it was strange that i would get 3 more MPG just going 500 miles away from my home, i think the crap for gas we have in cali acounts for alot of it, later

 

My mpg has been off about 1 to 2 mpg and I was beating myself up trying to figure out why. I think I have finally got it pinned down. Last year around mid August I installed a K and N FIPK on my 03 5.4 Screw. Everything was all peaches and cream. Now about 2 months ago I notice a 1 to 2 mpg decrease with gas. I tried several things and still no change. Well this is basically my first summer with the intake. Here in TX we have highs in excess of 100 degrees with high humidity and that is the problem. The intake is sucking in major hot air causing my drop especially when I am at idle in stop and go traffic. I will confirm this once temps cool off later around the end of this month and into next month.

 

that cant be my thing because i also have the K@N BUT I GOT BETTER mpg in the hotter drier higher elavation climate than i did in the lower elavation cooler more humid climate, just thought that was weird thats why i posted

 

I think its a combination of things.

1) the gas itself
2) the altitude
3) heat
4) humidity
etc

I get better gas mileage in Dallas than I do here in College Station, but for two main reasons. Its WAY more humid here in CST, and I dont do quite as much highway driving here than in Dallas.

 

Depending on where you are, you get different gas to meet EPA standards. There are so many different blends, it is insane. Within a state, you can get different blends between counties, even different from city to city. The special blends to lowere pollution, usually get less milage.

 

dont forget to add your 3" body lift so that will also effect your elevation and oxygen content but yes climate and elevation effect engine performance....

 

Exactly. If you live in a part of California with air quality problems, your fuel has lower energy content than fuels in other parts of the country. Many areas in CA are now using ethanol blends year round. Supposedly, our fuels only have 2.5% less energy per gallon, but the loss in mileage is MUCH greater than 2.5% on Ford trucks.

FWIW, last time I went out of state (Reno) and filled up, I got about 3 mpg better coming home than I got going there with CA gas. Our CA gas sucks.

Local gas quality makes such a difference in mileage, it is impossible to compare your mileage with someone who has the same truck but lives in an area with different gas. I can't tell you how many threads I've seen where people in other states claim 10% - 20% better mileage than I get with a similar truck.

 

After getting my scan guage I was not surprised, but yet disturbed to see that the intake temp was over 150 degrees when setting at a redlight with the outside temp at 108 here in Arizona. It is normally within a couple of degrees when at highway speeds. But the temp is usually 4-8 degrees hotter than the outside air when traveling around town. I don't think I will tamper with the intake system of my truck other than a K&N filter. It will be interesting to see the temp spread when it cools down. No wonder we get better mileage in the winter!!

 

it's the gas ,In theory, you should make more power at lower elevations.