OK, I swapped over to 60lb injectors on my 8.1L for the turbo. The turbo isn't currently on, so Im just running a tune similar to stock just modded for the injectors. Seems my mileage had dropped (if possible on a 8.1L) since the install. Used to get about 12-13, now I get no better than 9, and its been like this for over a year. I know the injectors just allow more power, but actually add NONE. I'm not sure what the problem is. Seems there is something a little wrong somewhere, maybe a Vacuum leak on an injector? It never wants to idle smooth

 

Your tune for the injectors is not right. It should get the same mileage if the tune was right.

 

injectors should not effect gas mileage; you are obviously running rich which is because the tune is off. I went from stock 5.3 (27lb/hr?) to 60lb/hr and see the exact same mileage.

 

I agree... the injection systems on our trucks are controlled by computer and will supply only as much fuel as is required. upgrading to bigger injectors will not affect mileage unless otherwise tuned.

 

Thats what i thought. I wander if something else isnt wrong

 

I disagree. Larger injectors have less precision at low RPM's/idle. I read it once in a tuning book but can't remember the exact reasons why but unless I've lost my marbles (which is possible), larger injectors can cause you to lose mileage.

 

While true, they arent *that* bad at idle, and unless you spend a disproportionate amount of time there it would be almost impossible to measure. My fuel trims bring my idle to stoich anyway, although idle isnt as smooth as it was with the smaller injectors.

 

I run 72lb on my N/A 6L...my mileage sucks!!

 

well, if you've got the supporting mods that need that much fuel, it's hard to see why...

 

I don't, turbo is gone. There is no N/A 6L motor anywhere that needs 72lb injectors!