2014+ Gas Mileage (MPG) Topic

[peejaykay]

I have 750 miles on my NHT (3.73) CC LT and average 16-17 city, 22 hwy. Best of 29.1....according to dic!

[ToesonTheNose]

Had to do a trip to the other coast of Florida and it was all lower speed highways for over 4 hours one way, so I thought I'd see how high I could get my MPG. Worked out great since I've never passed so many police in that amount of time. Only outside mods are the Bakflip, AMP steps, and raised tire pressure. Max speed limit was 70 mph for 30 miles, but the rest was 60 or less. Also included my at the pump records for those who don't like the DIC numbers. My DIC averages .6 over what I calculate at the pump.

 

Jeez 4 hrs? did you take 192? I travel to my house regularly in Rockledge from Tampa and 2 hrs is the longest its taken me.

[Crf450r420]

Went to the south west coast really. 20610 Tamiami Trail E, Naples FL from Melbourne. No straight path.

[ToesonTheNose]

ahh yes, that is an all day event then lol

[bass mechanic]

'14 5.3L, 3.42 gear, 4x4. Crew cab, short bed. I have been driving between Tampa and Orlando daily since I bought it. Burning 87 gas, shell or the cheap brands. 4,700 miles on the truck today. Mileage has been getting good lately. I've been averaging 18.7 to the tank per the DIC. Hwy, trips to the gym, errands etc. I can easily do 16 city. Hwy is funny. Speed, time of day, etc varies a lot. I've done up to 22 and as bad as 18. But for the most part it's about 19.5 or 20 hwy. that's with cruise at 78 or 79, Ac on. Very happy with mileage. I hear rattle sometimes, like spark knock. It's the ECM getting everything it can out of the gas. I have a sneaky feeling if I ran 93 I could get more out of it. The programming on these new trucks is pushed to the limit for MPG's.

 

As a side note, I've been hand calculating fill-ups. the DIC is consistently 0.5mpg HIGH. I even used the same pump on one tank to rule out the pump variable. The DIC is giving a .5mpg inflation. FYI. My 2007 BMW 335i does the same thing. About .5mpg high. Must be the law allows them to be within a certain amount and they obviously want people thinking the car is getting the best mileage possible on the test drive to BUY them.

Your mpg will improve with 91 octane fuel. A few years ago a guy I knew did an experiment by filling up a spare gas can and carrying it with him to get to the gas station. He ran 3 tanks until empty on 85/87/91 found the mpg was better each time. After the calculation was done discovered that despite the 91 costing the most he got more miles to the dollar and better performance with the 91.

Also your engine has to constantly adjust timing due to knock with low grade fuel. Whenever timing is retarded you get less power from the engine and less mpg.

Your variances in mpg probably have more to do with temperature because when it's cold outside there is less chance of knock and the engine will need to compensate less. It doesn't have to pull as much timing to avoid knock.

Knock is a very bad thing at the very least it will cost you economy, but it also causes rod bearings to wear prematurely as well as main bearings. Worst case you can burn pistons and valves.

Do yourself and your engine a favor and stop being a cheap ass. I just checked fuel prices here and today premium is 3.70 per gal unleaded (85) is 3.40 per gal that's a difference of 30 cents! If you put 20 gallons in you save 6 bucks!

You said you were using 87 so it's even less of a difference. But I'll use the extreme example.

Trust me your not saving any money! 6 bucks at 3.40 per gallon bought you 1.7 gallons of extra fuel!

At 20 mpg that got you an additional 35 miles per tank full. At 18 mpg it got you 30 miles.

If using premium fuel gets you just 1 mpg average better than 85 in 20 gallons you will have driven 20 miles more on the same amount of fuel!

So best case is you got 10 more miles out of a tank of low grade fuel. So congratulations! In the end you got 10 miles or .5 gallons worth of gas. Your total savings was actually only $1.70 for that tank.

If using premium got you better than 1 mpg average (and I'm certain it will) you actually spend more money on low grade fuel.

Ask any mechanic how dumb it is to put anything but premium fuel in any engine with a 12:1 compression ratio!

 

There's my .02 if you read this 35 times until it sinks in, you will have made up for the 1.70 you saved and start using premium fuel! Lol

Fwiw until today I had no idea what the cost of fuel was. I had to look it up to make this post. I think the last time I used anything but premium was in my 1978 ford pinto. I swipe my card, select 91 (or 93 if they have it) and let it run until it stops. Select "no" for a receipt and leave. I couldn't tell you how much my last full up was and I don't care. I do monitor my mpg and try to drive efficiently whenever I can. But at the end of the day I can only control my driving, not the price of gas.

 

 

 

 

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[Ventilator]

How about 21-22 overall average on 87? With the exception of the 10 gallons of 88 (87 not a choice) I put in in Wyoming to top off my tank, all I have burned is 87. I did get 26.1259 MPG on 13.810 gallons (360.8 miles) burned off that tank of 16 gals of 87 and 10 gals of 88 mixed going through Yellowstone and coming out the East side to Cody, WY. This was a lot of low speed (45 and under mostly) in Yellowstone and switchback dropping in elevation to Cody.

 

I might need to experiment with 89 back here on flatter ground and 750' elevation? But I don't have any spark knock with 87, and I can easily get 24+ MPG on the highway (55 MPH). The 5.3 is designed for 87, and I get great mileage. I was getting great mileage at higher elevations in the Rockies. So if we use the recommended 87, we are all Cheap Asses? Never made the connection!

Edited October 2, 2014 by Ventilator

[KARNUT]

Mine performs better and gets better mileage with 93 gas. I drive the same roads and get gas at the same place 90% of the time.

[Isriam]

i'm actually keeping a log of every tank, the octane of the gas, the mpg, and where it was purchased. on 6.2l i'm getting the same or less mpg i do with 87 so far. i can tell a difference in power though, 93 is much easier to keep in v4 and accelerate without pushing hard on the pedal.

[darkfox1]

about 21k miles on my '14 5.3 4x4 LT CC

 

Best mileage I've been able to get so far (I've only had it 1000 miles) is 20.9.

 

Average is 18.9.

 

I run 87 octane and do a lot of back roads and interstate driving, stop n go has been minimal since I've owned it.

[CAtaylor]

i'm actually keeping a log of every tank, the octane of the gas, the mpg, and where it was purchased. on 6.2l i'm getting the same or less mpg i do with 87 so far. i can tell a difference in power though, 93 is much easier to keep in v4 and accelerate without pushing hard on the pedal.

That is because you are retarding the timing on 87 due to engine knock. You should be running atleast 91 with that engine. I have the 5.3l with lower compression and load due to the gears and the amount of KR is scarry on 87. I run premium and they recommend 87 on mine. They recommend premium for your engine; I would be scarred to death to run 87 in a 6.2 all the time. If the knock sensors fail pretty sure that motor would toast. I would love to see a log on one of you guys trucks with the 6.2 running 87.

[glcbn]

That is because you are retarding the timing on 87 due to engine knock. You should be running atleast 91 with that engine. I have the 5.3l with lower compression and load due to the gears and the amount of KR is scarry on 87. I run premium and they recommend 87 on mine. They recommend premium for your engine; I would be scarred to death to run 87 in a 6.2 all the time. If the knock sensors fail pretty sure that motor would toast. I would love to see a log on one of you guys trucks with the 6.2 running 87.

 

Is there really that much difference between 11 and 11.5 : 1 compression ratio?

I would think higher octane would benefit both engines when it comes to engine knock.

[CAtaylor]

 

Is there really that much difference between 11 and 11.5 : 1 compression ratio?

I would think higher octane would benefit both engines when it comes to engine knock.

Higher octane definitely does benefit both engines. As far as the actual difference in .5:1 compression ratio, I really don't have a clue what that calculates out to compression wise. I just know that if the 5.3l benefits from it the 6.2 will benefit more due to the higher compression. The 6.2 could be set up completely different timing wise though so not sure. I know the 5.3l timing is very aggressive from factory. That is why I would be curious to see a log someone has done running 87 Edited October 4, 2014 by CAtaylor

[glcbn]

Higher octane definitely does benefit both engines. As far as the actual difference in .5:1 compression ratio, I really don't have a clue what that calculates out to compression wise. I just know that if the 5.3l benefits from it the 6.2 will benefit more due to the higher compression. The 6.2 could be set up completely different timing wise though so not sure. I know the 5.3l timing is very aggressive from factory. That is why I would be curious to see a log someone has done running 87

 

There is definitely a difference when I put 93 in my truck. I really can't explain it, the engine just "feels" different.

[PapaD]

14 silverado LTZ Z71 crew, 6'6" bed, 5.3, 3.42, stock everything, 16k miles. Went on 92 mile freeway run (each way), no traffic, no wind, 92 octane, 95 to 100 degrees with AC on, averaging 65 to 70 and got 26.5 mpg one way and 26.1 coming back. I drove like there was an egg under my foot and was in V4 mode except on uphill grades. Truck does great on the highway, generally gets 15.5 to 17 in city. Was getting 22 to 24 highway and switched to Mobil 1 0-20 oil and mileage went up to 26; not sure if the oil raised highway miles but mileage went up right after changing. So far, truck is exceeding my expectations.

[FL335i]

Im gonna do 93 next tank. Fl has 87 89 93.