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MPG after tires/lift?

Ghilie

By Ghilie
in Modifications & Accessories

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Donstar Senior Enthusiast

Donstar

Posted
Posted
53 minutes ago, JerryCanada said:

I have the 5.3L with 3.42 gears. 2" level kit and 275/65/18 BFG KO2's on  it. I get anywhere from 10.5 to 12 L/100km on highway and 14 to 17L/100km in the city. My opinion is that the 5.3L is worth the extra $ as a bigger engine will not work as hard to push the truck around and also being the most popular engine can be a plus in the long run.

Sounds logical but a 4.3 won't be straining with this level and tire combination.  The 4.3 has ample power for the task and the 5.3 has even more!  

Ghilie Enthusiast

Ghilie

Posted
  • Author
Posted
8 hours ago, JerryCanada said:

I have the 5.3L with 3.42 gears. 2" level kit and 275/65/18 BFG KO2's on  it. I get anywhere from 10.5 to 12 L/100km on highway and 14 to 17L/100km in the city. My opinion is that the 5.3L is worth the extra $ as a bigger engine will not work as hard to push the truck around and also being the most popular engine can be a plus in the long run.

That is the exactly the information I was looking for.  Thank you!  Also the same tires I'm looking at.

8 hours ago, GoBlue2014LT said:

2014 4.3 L - stock I was getting 18 average which is 75% highway 25% city. After 2.5” level and LT275/70/18 I am now around 15.5 MPG total after about 1200 miles on this setup


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Perfect, thank you for that real world information.  Do you ever regret not getting the 5.3, or do you have plenty of power?

GoBlue2014LT Enthusiast

GoBlue2014LT

Posted
Posted
Perfect, thank you for that real world information.  Do you ever regret not getting the 5.3, or do you have plenty of power?


4.3 has plenty of power for normal driving but for towing purposes I wish I had the 5.3 or 6.2. I bought the truck used. Next truck will be be either 6.2 or HD just so I can get a bigger camper.


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aseibel Senior Enthusiast

aseibel

Posted
Posted
On 10/31/2017 at 11:25 AM, youn1033 said:

These responses give me some concern as to whether or not there's an issue with my truck...

 

I've got a 2018 Denali w/ 6.2 & 8-speed. It is leveled with 33x12.5 Nitto Terra Grappler G2's as well as a Retrax ProMX rolling tonneau (thinking less drag here) + a Borla Touring GMPP exhaust. I have been REALLY babying this thing on acceleration, foot off the gas on hills, etc. & while driving my daily commute down a straight shot of I-10 w/ >90% being Highway, I STILL cannot seem to crack an average of 16mpg for at least 1/2 of a tank... 

 

Note: I was getting essentially the same results prior to the exhaust as well.

 

Anyone know what might be going on?? This truck has 2,200 miles on it.

The stock tire size is 265/65/18 = 31.6" tall x 10.4" wide tire.

You have significantly larger tires + a lift. So you have drastically changed the aerodynamics of your ride. Plus your speed on the freeway makes a big difference. You lose a lot of fuel efficiency increasing your speed from 65 mph to 75 mph. The EPA tests are done at like 55, which isn't even freeway speed, but they still call it highway. I'm guessing you drive much closer to 80, which will also kill your MPG. The tonneau cover barely makes a difference, as well as the exhaust. Maybe a fraction of 1 mpg combined over stock.

NitroDatsik Senior Enthusiast

NitroDatsik

Posted
Posted
16.5-18mpg being average or HWY?  Thanks for the reply.
90% highway

2014 Silverado 2WT 4.3 V6
Instagram @egroj_legnar
YouTube.com/jorge_dropkick_rangel

youn1033 Enthusiast

youn1033

Posted
Posted
1 hour ago, aseibel said:

The stock tire size is 265/65/18 = 31.6" tall x 10.4" wide tire.

You have significantly larger tires + a lift. So you have drastically changed the aerodynamics of your ride. Plus your speed on the freeway makes a big difference. You lose a lot of fuel efficiency increasing your speed from 65 mph to 75 mph. The EPA tests are done at like 55, which isn't even freeway speed, but they still call it highway. I'm guessing you drive much closer to 80, which will also kill your MPG. The tonneau cover barely makes a difference, as well as the exhaust. Maybe a fraction of 1 mpg combined over stock.

I agree with the aerodynamics portion and the fractional difference from the exhaust/tonneau, however everything I've read said that you're looking at 1.5-2 for just a level and 33s.

 

Even if that exhaust/tonneau offers nothing in return, if a truck shows to get 21hwy as "tested", and there are guys on here reporting 19-20hwy, 15.5-16 still seems pretty far off base IMO. 

 

Also to clarify, as much as I'd love to (and otherwise would) drive (above) 80, I've been doing this test for science! I'm sticking to the 65-70 range on the highway consistently until I get this all figured out.

aseibel Senior Enthusiast

aseibel

Posted
Posted

If you didn't test and record your mileage before you got the level & tires, unfortunately you will never know exactly what your truck was getting stock. Mine is still pretty stock, also with soft tonneau cover. If I set the cruise at 70 and drive for 2+ hours on the freeway, I have hit anywhere from 19 -22 mpg on a full tank. Mostly depending on wind conditions, but around 19.5 - 20.0 would be normal. I have the 5.3 with the factory rubber. I can't wait to put some real all terrain tires on and compare my changes.

 

The 1.5-2 mpg loss for a level & tires is a minimum. It can only get worse from there. Your tires probably are causing you that much of a handicap. The width and tread pattern matter a lot on the highway.

 

  • 11 months later...
Badcummins59 Enthusiast

Badcummins59

Posted
Posted

With my 5100’s and 305/55-20s I get 13 on the highway. 5.3, 3.42 gearing but I also set the cruise at 74

jimmyboy8301 Senior Enthusiast

jimmyboy8301

Posted
Posted

I have a 4.5" Zone with 33" Nittos and 22" AF's. I have the 6.2L with 3.23's and the 8spd. If I set the cruise to 75 i'll average 17ish MPG's

TXGREEK Senior Enthusiast

TXGREEK

Posted
Posted

2018, CC SLT 6.2 4X4, 2.25” level, +1 offset, 285/60/20’s 23 mpg highway at 65, 21-23 depending on terrain at 72+

SuperChips performance and use Lucus fuel treatment every other tank.

9b6f2bbb160d4de2370b2e57d7c0daf5.jpg


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  • 1 year later...
EJRTexas New Member

EJRTexas

Posted
Posted

Got this issue also now. I used to get about 15 MPG city and about 18 MPG hwy if I was lucky. Suddenly i'm getting about 13.5 city and 16 hwy.. Not sure what happened...

 

Configured: 
2015 Sierra 1500 5.3L Z71 (Not sure on gear ratio)

1" level (I think from factory) 

33" X 12.5" Toyo open country AT2

 

Not sure what do with this. If anyone has suggestion or thoughts please let me know what could have happened suddenly to drop in MPG. I would like to know before I make a 1200 mile trip.

 

Unrelated note: Just took the vehicle to the dealer for the recall on brake pedal pressure and oil change and rotated the tires. Said emissions was fine and nothing seemed off. 

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