Do they make such a thing? Or is that like getting a Diet Pizza? Or finding Big Foot, discovering a cure for the cold or learning what women really want?

Looking for more power and gas mileage out of a 2017 GMC Yukon XL with a 5.3 and a 6 speed
Headers / Exhaust?
Taller Gears for City driving?
Tune?
Head Work?
Intake messaging?
Throttle Body porting?
Not letting my wife drive it?

Thanks Gents!

Chad

 

more power = less gas mileage

 

You could still add power and retain the same cruise mpg or very slightly increase it but don't expect much.

It probably already has 3.42's, I wouldn't want to make it any worse by going to 3.23's or something like that.

Lowering the truck, reducing rim weight and tire weight could gain you some mpg but again it wouldn't be noticed much. In the end it's still a brick rolling down the road. Driving habits and how fast you drive will have a far greater impact on miles per gallon.

 

Technically if you can delay intake valve close angle with a longer duration cam, you have to open the throttle more to maintain the same torque. The result is lower pumping loss. The side effect is moving torque higher in the rpm range, so you lose peak low end torque and gain horsepower. However you can't just throw any old big cam in it because if the intake and exhaust valves are open simultaneously, you will likely draw fuel straight through the cylinder.

 

What women really want, security and money? Let me know when you figure that one out And if you have diet pizza you'd better figure out how to have diet beer. Anything that could reduce pumping losses and increase low end. I would do a drop in filter and possibly 1 3/4 headers however I'd hate to do the headers on such a beautiful ride. When I had a 73 truck 454 headers made the low end incredibly increase off idle and increased mileage so.... Then finally a great tuner and most importantly driving habits. I drive like the old man that I am most of the time. Unless I see a young buck that needs a lesson in humility. For mileage I just drive my little 5 cyl. Colorado. 27 on the highway.

 

My wife has a lifted 05 Tahoe on 35"s with 4.56 gears.
When her original 5.3 ate a lifter I put a l33, btr stg 2, milled the heads, nnbs intake with a 90mm throttle body.
It actually gets about 2mpg better mileage now. It also gets better mileage towing.

 

She on a 60 or 80e? How does it snap off the line with 4.56 and 35s?

 

Currently a 60e.
I have a 80e for it, just need to get around to swapping it in.
Its the wifes kid hauler but I also tow a travel trailer and my truck to the track so I am making it how I think gm should have. It also has a tru trac. It tows amazing now and it is still alot of fun to drive, not the quickest thing around but peppy enough to get me in trouble still. Lol

 

But....are you going to recoup the cost of the modifications or tune with the increased fuel economy?

 

depends on how long he keeps the truck.
my 4.30s actually helped my mileage until i drive faster than 70mph, especially with the trailer.
headers & tune are easy helpers.