Gear ratio to hit 20 mpg or close HWY 01 Yukon XL

[LordWayback]

Those saying about “just get a economy car” I have to use my truck for work Atleast a couple days a week I’m adding a onboard air system so I can continue to use it as a service truck a lot of the time when the fork lift is in use I have to tow a trailer across the yard (huge work area) or do something that only a truck will do like carry commercial grade pressure washers even if the weight isn’t a issue the size is. I’m at a point to where I Atleast moderately improve mileage or I’m burning a hole in my pocket even on E ($4.19 a gallon) I’m running 85 octane pump gas same gas station every fill up. I’m considering a smog exempt Dodge Dart that I’d do something stupid to like a k swap to save those Pennies. About my tires they won’t hold 60 psi (for long) but the tire shop can’t locate a leak and they’re cheap as can be from the previous owner I’m hovering above 13 mpg and it’s killing me even granny driving.

 

[LordWayback]

Which engine do you have and what is your gear ratio now? Which tire size are you running and what are they?

Slow down and let all the nuts fly past you wasting their gas.

5.3 factory 01 slt k1500 Yukon xL ratio , 265 60 r18’s so a smidge bigger than factory cruise control the entire way I don’t really go above 70 I let the felony commuters pass me while I sit in the slow lane

 

[LordWayback]

The cost of a new car will surely be more than what he spends on "extra" fuel to operate his truck. Even re-gearing will take a long while to pay for itself.

Like you wrote, he outta keep it in tip top shape maintenance wise. Get all the extra weight out of it, don't need fishing weights or a bag of charcoal in the back unless one is going fishing.

He could run the tires 2-3 more psi than the door sticker calls for at the expense of ride/comfort and tire life.

I really gotta take out the extra junk calling me out here!

 

[LordWayback]

unless there is some reason you "have" to have a SUV then sell it and buy a 4-cyl economy car, these things are simply not fuel efficient, all you can do is gramma the hell out of it, basically be the slowest person on the road, do not accelerate, do not exceed 55-60mph, brake very early, draft whenever possible, do not sit and idle, turn off the ac, keep the windows up, tires inflated properly.

It’s probably the hundreds of pounds of extra junk in the whip because of work or f all

 

[Doubeleive]

It’s probably the hundreds of pounds of extra junk in the whip because of work or f all

could be, find a old station wagon or minivan and yank the rear seats out, plenty of room, pickups are not as secure but a colorado with a shell on the back maybe

 

[LordWayback]

He could try to track down one of the 2.7 turbo Silverado's.. The fuel savings should be around 300-350 a month. Thats half a truck payment, or better, right there. Or even track down a DM Suburban (much bigger truck payment). A older EcoDiesel Ram 1500 can be had for around 20k or less. Thats right around 400 a month in payment.

I think you are going to be LUCKY to get 18mpg out of your current rig. And thats including swapping over to a GU6 Gearing.

Or do as recommended, and find a eco-beater, like a Prius, Matrix, Vibe, Prism, etc.

At the end of the day.. If you are worried about MPG... You bought the wrong rig.

I would bend over to get 18mpg even if I had to rip out the 4th out of the second row the entire 3rd row 90% of my junk and re gear. That’s a 5+ mpg gain if I’m driving city 18 combined Would be game changing with just how much I drive for work. Check other replies just to grasp how much extra junk I have.

 

[LordWayback]

could be

I have some seats that can come out and stuff scrapyard bound.

 

[LordWayback]

Its kinda off.. But.. gives an idea.
My 2006 Saab 9-7x 5.3 AWD has the 3.73 Short Wheel Base, weighs 4500 lbs (estimated), and gets 15.8 routinely (AFM/DOD Deleted). Nothing in it but me and my lunch.
My 2004 GMC Envoy 4WD 5.3 has the 3.42 Long Wheel Base, Weighs 5980 lbs (verifed by scale before kids), and gets 16.7 routinely (No AFM/DOD). Plus: 2 kids, 1 Car Seat, 1 Toddler seat, 1 Stroller, 1 wife with her kitchen sink purse, various toys, and kid stuff.

Both are the same truck, except Envoy is a XL. Both are 4L60E.
3.42 only really shine for fuel mileage in highway cruising. If your in the city, its worse than the lower gears.
I will admit I probably loose a few tenths because of the AWD on the Saab.

Based on the OP first post, regearing his truck is not going to help, in fact, it may make it worse.

Why would it make it worse I drive over 60 miles a day on a bad day all freeway minus like 4 miles city the city mileage would tank but over the 50+ other freeway miles it’d make a difference?

 

[intheburbs]

A GMT800 isn't gonna get 18mpg, no way, no how.

A 900 might have a shot with newer engine cals, AFM, the 3.08 rear and the six speed.

Tires make a huge difference. You want a rock-hard compound in a highway tire. I know my Goodyear Duratracs might be costing me as much as 2 MPG.

 

[LordWayback]

No one's said to lower it and toss heads/exhaust on it hehe

I would scrape everywhere with how bad the roads are, if I wanna park at my siblings house , some days at work if I don’t park like a jeep I either get hit my cars been hit 3 Times because of the ****** California drivers PARKED or my boss complains that I’m taking 2 car lengths worth of space. the 3rd image was the 1st hit and run. I was leaving work went to put junk in my trunk saw it went on security camera and a white Honda HIT MY SHIT like there’s literally 3 lanes worth of space next to my shit and they hit and run me they didn’t have a front liscense plate. We did see their front bumper get ****** up , police were called and they said “no plate no case” AND THEN AFTER THAT SOMEONE MADE THE PREVIOUS OWNERS DENT WORSE AND RAN but that was at night so the security camera didn’t catch their plate of course, 3RD ******* TIME: a Toyota SUV Decided to HIT MY FKNG FRONT BUMPER AND FLIP THE FASTEST U TURN AND RAN don’t drive in Atascadero California guys. you can kinda see it in the first pic my bumper is dangling after new mounting hardware because it doesn’t line up anymore. You see the white line? That’s the closest the road gets to my car at work AND THEY ******* HIT ME 3 TIMES.