I thought I was happy..........bad mpg

[Turbo1Ton]

I wonder how much the poor tank vent has to do with everyones skewed numbers? If you install the better tank vent you gain 3-4 gal. capacity right? Are guys sometimes getting more fuel in and sometimes less, due to the funky air gap in a stock tank. This of course would account for a large swing in calculated mpg, and a large gap between calc and overhead.



Sooo those of you that have done the vent mod, pipe up and tell us what your getting since you now have consistant fill-ups!

I had consistant fill-ups before the tank vent mod. It would take me approximately 20 minutes to fill-up but I always fill-up until the fuel is at the top of the filler neck (usually covers the vent hole). So if you don't have the mod and aren't filling it up like that then yes, there will be some skewed numbers. I haven't had the vent mod long but I am confident that my numbers aren't gonna change that much, just the amount of time I spend at the pump.



Jeff

 

[mikeberry]

Wrong, all it does is allow to fill up faster, it does nothing for tank capacity

Thats what I ment. You will gain the capacity for the same amount of time at the pump. (i. e. if you took a pre and post mod truck and filled them with the same pump until they click off, you will likely have more fuel in the vent mod truck. )

I was thinking of guys who were not willing to spend the extra time each time. Maybe they let it foam into the neck one time. The next time they saw fuel in the neck before it glugged back down. The next time they let it click and saw some fuel so they stopped. What I mean is that before a vent mod the fueling proceedure will be less consistant.



For guys that know what a true "top-off" is before and post mod, no I don't think there will be a difference.

 

[Jack in Alaska]

Tank vent

I tend to agree with the slow fill. I did fill mine to the top but I thought I was going to have to send out for lunch as it took so long. Oo.



What is the "tank vent mod. " Please enlighten us new 3gers.

 

[WStephens]

I reset mine every time I fill up and reset the fuel economy when ever conditions change and it seems to be real close to hand calulations that I am comfortable with with the display says. if I am not I hit the reset and see if it improves or gets worse. I have also found that if I drive like I have an egg under the pedle my mileage gets much better than racing from stop light to stop light. When out on the highway I try to accerate by using my big toe instead of my foot and it does not impact the mileage as much.



I have also changed the air filter for the new Amsoil filter and modified the air box to pull cold air from below the frame which helped a lot.

 

[Turbo1Ton]

Jack,



Here is a recent post about the fuel tank vent mod.



https://www.turbodieselregistry.com/forums/showthread.php?t=153508



If you look in Spooled-up's signature there is a link to it. Basically you plug the factory vent line which is right next to the filler hose and move the vent to the highest point in the tank. It uses up the "expansion" area that the manufacturer built into the tank but you use this anyway if you do the slow fill method.



Jeff

 

[Jack in Alaska]

Back home from my trip. Total miles 614. Fuel used 40. 1 gal. That gives me 15. 4 mpg. The overhead was 16. 1 mpg.

My trip was half on real snowy roads and the other half on wet sloppy roads all and 1/2 of it was mountainous.



I did refill just as i did before and it took a long time again. Oo.

Now to chase down the vent problem and it looks like the post above will help me out... ... . thanks



That 3g truck is d--n fine to drive though. Glad i bought it.

Saw my old one on the lot today. Felt like I lost an old friend.

 

[DDevers]

I drive my truck like a grandma and get excellent mileage with it. On the highway at 68 mph (2000 rpm) I get between 21 and 22 mpg. Around town with all the hills we have and traffic lights, I get 18. 5. I have seen people that call those of us that get good mileage liars. I have no reason to lie to you. I drive like I have the proverbial pine cone between my foot and accelerator and hardly ever go above 2000 RPM. My wife and I are both amazed how an 8200 behemoth like ours can get that mileage.



One time when I was impatient and stomped on it to get out of a parking lot and into the traffic, I saw the overhead drop . 4 mpg and that was with 400 miles on that tank load. Since then, I just sit and wait a few more minutes if required.



Big Blue consistently gets about 2 mpg better than our old truck, a Toyota Tundra.