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Hey guys,

Recently installed a 4" BDS lift kit on my 2011 silverado 1500 ext cab. Love it forsure, but I was so suprised how much it affected my gas mileage. I did expect a little difference, yes, and it really isnt SO bad, Im averaging about 12-13 after averaging 15-16 - city. On the highway I've gotten 22, now I get 16 at best. Any ideas???

I've heard that a k&n CAI would help, also a tonneau cover. Myths, or for real? Any other ideas would be much appreciated! Thanks!!
 

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The amount of money you would spend on those "gas savers" would almost negate any increase in gas mileage. Might as well just spend the money on more gas and accept the fact that when you get a lift kit and aggressive tires you are going to lose gas mileage.
 
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The amount of money you would spend on those "gas savers" would almost negate any increase in gas mileage. Might as well just spend the money on more gas and accept the fact that when you get a lift kit and aggressive tires you are going to lose gas mileage.
Yes! You took the words out of my mouth. Only thing that might be worth the money is gears. How much bigger did you go in tire size? Have you gotten the speedo calibrated?
 

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Did you adjust the trucks computer ( programmer or custom tune) for the taller tires? Also I lost about 2mpg's when I lifted my truck back in '05. I gained it back with a programmer, CAI, headers and exhaust. I did regear my truck also, went from 3.42's to 4.10's.

---------- Post added at 06:24 PM ---------- Previous post was at 06:23 PM ----------

Also, your truck looks great!!:great:
 

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I don't know if you like the looks of air dams, but that's one solution. It will make the air start going back around your truck, rather than under it where it catches on every irregularity & creates wind resistance.
 

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Switching all of your fluids to synthetics ( engine, transmission, diff's) will help with MPG's a bit as well.
 

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I saw a video of a truck dynoed with stock tires and then 33" tires. It lost 40 hp at the wheels with the larger, heavier tires. Thats most of your MPG loss.
 

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I saw a video of a truck dynoed with stock tires and then 33" tires. It lost 40 hp at the wheels with the larger, heavier tires. Thats most of your MPG loss.
I saw that vidoe too STB. I think it was posted up here on GMTC. Didnt they do the base dyno test with a much much smaller than factory tire though? I know there has to be a difference (I felt it going from 265's to 295's) but just not a 12% decrease in HP.
 

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You probably lost the MPG from 3 things.
1) If the new tires are 3" taller- it would mean you are going 10% farther than your ECU and odometer think you are-that would be 1.5-2mpg maybe.
2) Bigger wider tires have more rolling resistance,and more aerodynamic resistance- both eat power/fuel
3) The taller truck now has more aero resistance because it in effect has more frontal area.True is is more or less the same size, but the extra air going under it makes it really dirty-this is why NASCAR etc have so littler ground clearance,and the cars have chin spoilers and cowls under engine bays.

If you didn't adj your ECU for the taller tires, you are probably just 3-4 mpg down not 6 mpg down. Oh, and heavier tires wheels do take more energy to accelerate-this hurts city mpg-doesn't hurt hy mpg as much(harder on brakes also- harder on diff etc also).
Charlie
 

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Alston, the video I saw had a NNBS red truck. They did use a low profile tire for the first dyno run and then a 33" tire.
 

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I put a K&N filter in the stock housing along with changing the exhaust from a 2 into one into a 2 into 2 with a Flowmaster muffler on my '98 Suburban after the first 100k and it seemed to help with the power a little. At 243K I get 16 mpg all around which is not much different than it was 10 years ago. I have heard converting to electric fans is good of a couple of MPG but am skeptical.

Like everyone else has said, bigger wheels on a truck that is higher in the air is going to take for power to move - period. You will be hard pressed to get much, if any of that back.
 

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Getting lower gears (numerically higher) will help restore some of that lost power from the bigger tires and lift, and it might help save MPGs in the city as it will take less power to move the truck and it will take the strain off of the engine and tranny, but you will lose mileage on the highway. Lower gears makes the engine and tranny turn more RPMs at highway speeds and that's why highway mileage might suffer.
 

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All good advice here. While the mods suggested - custom tune, synthetic lube, e-fans, etc. will help some, probably the most important thing is going to be driving style. Easy on the right foot around town, reasonable speeds on the highway. I do 65 on the highway. Almost everyone passes me. I get 20 mpg in a 96 Tahoe 4wd with 210K.
 
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