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

[LordWayback]

I drive like 4 miles in the city a day otherwise I’m on the freeway what would be the best diff ratio to close in on 20 mpg (that’s known) 13.5 mpg combined is killing me with these prices averaging 5.50 for basic.
I don’t mind shelling out money or working on At least the rear diff but 7 mpg or a little less would make a huge difference I know the new trucks with AFM and highway diffs close in on 30 mpg Hwy.
(28.5 mpg registered on a factory turbo 4 cylinder Silverado with said gearing) hwy I think 20 mpg with a tune and diffs can be obtained without Active Fuel Management lifters. I spend 500$ or more per month on basic gas alone. So 20 mpg would drop me closer to 300 or less per month in fuel.

 

[LordWayback]

You may say “then why didn’t they do that from the factory” because of city mileage turning horrendous.

 

[LordWayback]

Yukon gear and axle sells a 2.73 which would obliterate all my city mileage but would be wayyy better highway

 

[intheburbs]

Probably easier to just find a junkyard 3.08.

 

[swathdiver]

I drive like 4 miles in the city a day otherwise I’m on the freeway what would be the best diff ratio to close in on 20 mpg (that’s known) 13.5 mpg combined is killing me with these prices averaging 5.50 for basic.
I don’t mind shelling out money or working on At least the rear diff but 7 mpg or a little less would make a huge difference I know the new trucks with AFM and highway diffs close in on 30 mpg Hwy.
(28.5 mpg registered on a factory turbo 4 cylinder Silverado with said gearing) hwy I think 20 mpg with a tune and diffs can be obtained without Active Fuel Management lifters. I spend 500$ or more per month on basic gas alone. So 20 mpg would drop me closer to 300 or less per month in fuel.

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.

 

[Doubeleive]

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.

 

[intheburbs]

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

I resemble that remark...

 

[Mudsport96]

Well even my wife can manage 15.5 to 16 with her driving, with the 5.3 and 3.42s at 55-60 mph. With lots of short trips between her 15 mile highway drive to work. So what is your setup and how do you drive?
Also a 2 73 will kill your mileage. Most likely unless you are running 75+ you wont be turning the rpms that you would need to stay in overdrive with light enough throttle to get better mpg. (Lugging the engine)
So how fast do you drive?

 

[Mudsport96]

Some examples of my rpms at speed vs a 273 gear.

 

[S33k3r]

The number one thing you can do is drive with a light foot. Number one thing. Now, in terms of technological solutions, these are the only things I can currently think of:

1) Drive with a light foot. It needs to be emphasized.
2) Convert to efans. They will bump mpg a tiny amount, but they will bump it up.
3) Tune for higher octane.
4) If you are wanting to regear for MPG, I suggest changing your cam so you can develop your torque as low as possible in the RPM band.
5) I have heard a turbo can help but, once again, you have to keep a light foot...
6) Reduce vehicle weight. Take out some seats, for example.
7) improve aerodynamics.
8) Not sure how you would do it, but you could also add active fuel management, theoretically. I mean, I don't advise it, but it would save gas.
9) By a cheap, fuel efficient beater for daily driving, and keep your Yukon for fun. And the beater is likely cheaper than most of the above.

That's all I can think of. Good luck.

 

[swathdiver]

9) By a cheap, fuel efficient beater for daily driving, and keep your Yukon for fun. And the beater is likely cheaper than most of the above.

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.

 

[S33k3r]

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 was thinking of a real POS beater. 20 mpg is EASY to hit in even older economy cars. That was why I was suggesting it may be cheaper than all the upgrades to his Yukon.

 

[Doubeleive]

The number one thing you can do is drive with a light foot. Number one thing. Now, in terms of technological solutions, these are the only things I can currently think of:

1) Drive with a light foot. It needs to be emphasized.
2) Convert to efans. They will bump mpg a tiny amount, but they will bump it up.
3) Tune for higher octane.
4) If you are wanting to regear for MPG, I suggest changing your cam so you can develop your torque as low as possible in the RPM band.
5) I have heard a turbo can help but, once again, you have to keep a light foot...
6) Reduce vehicle weight. Take out some seats, for example.
7) improve aerodynamics.
8) Not sure how you would do it, but you could also add active fuel management, theoretically. I mean, I don't advise it, but it would save gas.
9) By a cheap, fuel efficient beater for daily driving, and keep your Yukon for fun. And the beater is likely cheaper than most of the above.

That's all I can think of. Good luck.

true, with the money you would spend you could buy a junkyard dog and be good to go, tow company's and wrecking yards are your best bet. I have bought a few from tow yards they usually have the best deals even if it needs a little tlc, tires or a window or something. i bought a old beater toyota for $400 once drove the piss out of it for a few months while I saved up money for something nicer and then turned around and sold it for $400 as well.

 

[TollKeeper]

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.

 

[swathdiver]

I was thinking of a real POS beater. 20 mpg is EASY to hit in even older economy cars. That was why I was suggesting it may be cheaper than all the upgrades to his Yukon.

That much of a beater it's gonna be more trouble than its worth. Besides the cost, looked a few minutes ago on Craig's List, a cheap running car started at $2K for a real beater that was not a mechanic's special.

Then there's registration, tax and insurance on another car.

Prices are coming down anyway. Julia paid $3.93 for 93 at Sam's last night.

 

[SnowDrifter]

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

 

[Tom-M]

I have a 2022 Yukon Denali with the 6.2L engine. When I drove it home from the dealer, I was getting 14 mpg on the highway. Getting a few miles on it for break in, I am now getting 20-21 on the highway and mid 20's and a high of 28 mpg over a 25 mile drive at 55 mph. One thing for sure, your gas mileage is directly proportionate to the weight of your right foot.

 

[TollKeeper]

You also have a lower gearing, plus more gears. He still has the 4L60. I bet he has the 3.73

He was also talking about lifting it in another thread, and that isnt going to help either.

 

[S33k3r]

You also have a lower gearing, plus more gears. He still has the 4L60. I bet he has the 3.73

He was also talking about lifting it in another thread, and that isnt going to help either.

We don't know if he has a 5.3, 6.0, or 8.1. We also don't know if he has a 4L60 or a 4L80. If he is a 1/2 ton, swapping to 3.42 will likely get him closer to his target. So, 3.42 gearing, eFans, different cam, tune for 93 octane. I think that at least gets him to 18 MPG, assuming a 5.3. He might get an extra mpg or two from removing second and third row seats, the roof rack, the trailer hitch and converting to a roll pan. If it is a 6.0 or 8.1, forget it. You'll only see 20 MPG with a tail wind, a tow, pushing it, or on heavy drugs.

 

[S33k3r]

FYI, in case it isn't clear, I work from home, so I can afford 10.8 MPG out of my Silverado. It gets 50 miles per week at worst. We are looking at getting an electric for my wife, between now and 2 years out. It will likely be our last new car purchase ever. My daughter is getting 13 MPG city driving, but is headed out to college to park it; her campus is a walking campus. When she graduates, we expect her to be able to cover gas, or we'll get her something fuel efficient.