i know the two are like an oxymoron, ive got an 09 sierrawith a 5.3 and im debating getting the on3 kit. its used mainly for work but also hauls my 6x12 enclosed trailer, for work, and with my track bikes in it, and also its going to e used to tow my toy hauler. 6400 pounds dry, fits 3 bikes, about 400 pounds a piece, plus all my junk, the weight adds up quick. the 5.3 has enough power to haul it all, but i could always use more. and id like t keep the trans from constantly dropping a gear any time i hit a slight grade change. i remember watching one of those trucks shows where they put a blower on a truck like mine and said that while towing the trans spent a lot less time searching for a lower gear, which is a bonus for me.

so i guess the question is, if i go with a turbo, 5-6 psi, as long as i keep her out of boost, day to day driving will i notice any change in fuel economy? i know in theory it should atomize the air better and increase fuel economy, so the guys who have a boosted 5.3 and are able to keep their right foot out of it, what kind of mpg do you get?

also while towing any heavier weight like what i mentioned above, what kind of mileage do you guys get? and have any of you compared mileage before and after the turbo just to see if its increased at all or has it taken a hit from it?

i boosted a car years back but i dont think there was ever a day where i didnt have my foot in it so i couldnt really get a good idea of the fuel economy lol.

the options for me are either this or to sell it in a couple years and buy a diesel but i just hate all of the castrations the new diesels have and the maintenance costs as well.

 

From what I have read if you are going to be doing a lot of towing you might strongly consider going with a supercharger. Anyone else want to chime in?

 

From what I have found it really depends on your right foot, I use mine as a daily driver and can match my stock mpg if I just drive around out of boost. Towing is tough as soon as it gets load on it it will start making boost and will need to be rich. This will be all up to tuning with low boost you don't need to be that rich and if you add meth Injection you can keep it cool and not just dump fuel in.

 

Any fuel increase will be thrown away as soon as you hit the throttle harder then now.
And you'll push the pedal more often and harder then now because its fun to drive.

Alls it takes is one good lunch to kill any gas mileage increase.

 

good to know, i was hoping that travelling at low boost at a lower rpm would cancel out the extra fuel the truck uses while towing at a higher rpm in a lower gear. a blower would be nice but any blower is 5k and up and thats out of the budget. meth injection isnt a problem, winter washer fluid is cheap enough to buy and a jug lasts a long time. it might just make more sense to buy a diesel and get almost the same mileage towing as it is empty, except the new ones arent as good as the old ones were with all the dpf crap and other such stuff.

i did some more reading on here last night and noticed that theres another post similar to this a couple pages in, and guys are saying they can do moderate grade climbs at a lower rpm and the truck stays out of boost or hits just a very low boost, but no mention of how thirsty it gets. really at 1-2 psi at 2000 rpm is it going to consume more fuel than it would having to tow at 4500 rpm?