Any tips for better mpg

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ROGELIO A GUZMAN

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Hey fellas. Any tips to get better mpg. Getting about 13.2 mixed. Maybe a drop in K&N, synthetic oil. Iridium plugs. Just wondering if any thing I can do. Thankz in advance.
 

wjburken

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Keeping your drive train properly maintained with fresh fluid will help with MPG’s. When was the last time you had the fluids changed in your differentials, transfer case (if 4WD), or transmission?

Outside of your drive train, you mentioned plugs, but I’d also go with new wires as well. Might clean your throttle body as well.

Then of course, there is proper inflation of your tires.

Others will likely offer other suggestions as well.
 
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ROGELIO A GUZMAN

ROGELIO A GUZMAN

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Keeping your drive train properly maintained with fresh fluid will help with MPG’s. When was the last time you had the fluids changed in your differentials, transfer case (if 4WD), or transmission?

Outside of your drive train, you mentioned plugs, but I’d also go with new wires as well. Might clean your throttle body as well.

Then of course, there is proper inflation of your tires.

Others will likely offer other suggestions as well.
Thank you. I just got this 04 denali xl. I'll start with all the fluids and follow your recommendations.
 

S33k3r

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Is your Denali All Wheel Drive (AWD)? If so, you are losing 1 - 2 MPG there. Things I've seen in other forums are proper maintenance -- plugs, wires, coils, -- a professional tune, and driving like @Doubeleive says. If you do the professional tune, I've heard higher octane tunes (93 for example) can reclaim a mile or two to the gallon.

Oh! Almost forgot: Converting to eFans will likely reclaim you about .25 to .5 mpg, as well as a few other benefits.
 

bill1013

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Sometimes just boosting the the octane to 93 helps wonders. My 2012 Yukon SLE is getting 17.0 MPG and I put 93 in the tank religiously. Burns hotter, cleaner and a little extra kick never hurts.

There was a time when I came into 110 gallons of aviation gasoline, which is purple and 145 octane. A friend of mine wanted some for his 2 door 68 Ford Torino (metallic green) that he drag raced on the weekends. I suggested 1 quart of 145 to 3 quarts of 93 to start. The kick he got was very noticeable and his time was around half a second better than without it. The only problem was the engine ran extremely hot as 145 does. Didn't matter to him, he was hooked. Next run he mixed it half and half and blew the doors off of the competition. Over a second better than with just regular 93. Well, his third run ended in disaster. He mixed it 3 qts. 145 to 1 qt. 93 and he came screaming off the line. It sounded absolutely awesome...until the engine started coming apart and the car caught fire. The fire was put out pretty quickly and the body wasn't damaged too badly, except for the hood and fender wells. Looked like a gorilla was trapped inside and tried using a sledge hammer to get out.

A little boost in the octane really helps. Burns a little hotter, burns a little cleaner and gives you a little extra umph when you need it. And I get better MPG. And I must admit...on occasion I do fill her up with regular (89) to save a few bucks. Aloha!
 

swathdiver

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Sometimes just boosting the the octane to 93 helps wonders. My 2012 Yukon SLE is getting 17.0 MPG and I put 93 in the tank religiously. Burns hotter, cleaner and a little extra kick never hurts.

There was a time when I came into 110 gallons of aviation gasoline, which is purple and 145 octane. A friend of mine wanted some for his 2 door 68 Ford Torino (metallic green) that he drag raced on the weekends. I suggested 1 quart of 145 to 3 quarts of 93 to start. The kick he got was very noticeable and his time was around half a second better than without it. The only problem was the engine ran extremely hot as 145 does. Didn't matter to him, he was hooked. Next run he mixed it half and half and blew the doors off of the competition. Over a second better than with just regular 93. Well, his third run ended in disaster. He mixed it 3 qts. 145 to 1 qt. 93 and he came screaming off the line. It sounded absolutely awesome...until the engine started coming apart and the car caught fire. The fire was put out pretty quickly and the body wasn't damaged too badly, except for the hood and fender wells. Looked like a gorilla was trapped inside and tried using a sledge hammer to get out.

A little boost in the octane really helps. Burns a little hotter, burns a little cleaner and gives you a little extra umph when you need it. And I get better MPG. And I must admit...on occasion I do fill her up with regular (89) to save a few bucks. Aloha!

My experience has been that the engines run cooler with higher octane fuels. Highest I ever used was 117, don't know what the equivalent is today, don't recognize the offerings on VPs website. Sunoco's 104 Unleaded was awesome though, I can tell you that, burned about a hundred or so gallons of that stuff way back when!
 

Danny3737

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Smooth and easy on the pedals is the most efficient and cheapest method. Preventive maintenance and tire pressure are equally important. Don’t waste your money on gimmicky stuff, you’ll usually hurt performance and mileage. Also, make sure your wheels are perfectly aligned as well
 

bigdog9191999

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being we have an 03 denali also, as many said keeping up on things is number one, tire type and size can make quite a bit of difference, as well as where your driving and probably the biggest is the how your driving it.

we get 12-14 on average with ours, but we don't baby it and have 285 druatracs on it ( I got 1-1.5 mpg swapping to snow tires on my avalanche) many of the items you are going to buy or pay for aside from upkeep will take a long time to pay for themselves, let alone save money.


using higher that needed fuel required will also do little to save money, as the little you could save will most likely be negated in the cost of the more expensive fuel.
 

bigdog9191999

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being we have an 03 denali also, as many said keeping up on things is number one, tire type and size can make quite a bit of difference, as well as where your driving and probably the biggest is the how your driving it.

we get 12-14 on average with ours, but we don't baby it and have 285 druatracs on it ( I got 1-1.5 mpg swapping to snow tires on my avalanche) many of the items you are going to buy or pay for aside from upkeep will take a long time to pay for themselves, let alone save money.

in my experience even the 5.3 like my avalanche and Tahoe only get about 1 mpg better average driving, and the 8.1 about 1-2 less. for about 5mpg across all the trucks, but with them all being close to 6,000lb bricks in the wind, none are going to stellar.
 

bill1013

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Aviation gas (145) is a very pure fuel. There are literally no additives to the fuel other than the purple dye that is put in to identify leaks in the tanks & fuel lines. The recip engines are usually air cooled and the pistons are horizontally opposed so every stroke is basically a full power stroke, compression, intake or exhaust. BMW motorcycles use this set up and they kick butt. Instant power the moment you hit the throttle. The bikes have similar, yet smaller, heat syncs like the recips do.

I've never really noticed an increase in my engine temp (analog gauge) with the 93 as the difference in octane level is not that big of a difference, but I like to think every little bit helps. And as my A&P instructor stressed, "Burning hotter is a complete burn and that helps the engine stay clean". No deposits from unburned fuel or it's additives, no clogging valves or lifters. I have noticed that I get 17.1 MPG with 93 and around 15 with regular or 87.

As to my friends 68 Torino I believe he was running straight water as a coolant, which you could do with the old Ford 289s & 302s. Which was popular back then. If you were doing day to day driving water will do for a while, but over time the corrosion that builds up are crippling to an engine at that time. But one big disadvantage to water is it evaporates rather quickly, especially when the engine is being put to the test. Like when drag racing. (Oh, and I failed to mention that this event happened in the summer of 1981.)

Nowadays, coolants have so many additives that prevent corrosion, aid in lubrication of pump, pump bearings & keeps gaskets supple to prevent cracking. In short, you really can't just run water in newer/modern vehicles because the engine is designed to remain cool with a certain amount of proper coolant, not just water. You might use water to get it to a service center, but to just run water is a quick trip to engine problems.
 

Joseph Garcia

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All good suggestions above.

I gotta tell you, IMO, the mileage that you are currently experiencing is not bad at all for that truck. The Denali, with its large motor, was not designed for great gas mileage, but rather for performance, whether it be for quick starts or for towing. Depending on what I'm doing, I can get below 10 mpg when I'm out by myself just horsing around, or close to 18 mpg when my wife is in the truck, who has zero tolerance for horsing around.

Your best option for increased mileage, as already stated above, is to adjust your driving (gas pedal usage) habits. That is hard, though, as it is really fun to push the Denali and its motor.

You could also opt for a Black Bear Performance tune, which could be built to focus on better gas mileage (versus performance), and the folks @BlackBearPerf could estimate for you, just how much better gas mileage is realistically possible with one of their tunes for your Denali. It would cost you somewhere in the neighborhood of $600 to get a tune, though.
 

Dantheman1540

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Another thing to consider is the LQ4s in the Denalis are pretty low compression at 9.4-1 that doesn't help efficiency or mpg. I agree with the people above that say your current numbers aren't bad for what you have.
 

Jenzenauer

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I replaced my factory exhaust with Cat back 3" Flow Master 40 series cause that is the sound I like and I have averaged a +.8-1.0 mpg improvement as long as I keep my foot out of the gas other than that it is really the only improvement I have noticed. that gets me to right around 16.0 mpg on 200k 4wd Tahoe with 5.3L
 

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