airflow plus bigger tires = bad mpg?

[Mortis Mango]

I purchased a 2015 silverado 1500 LT, 5.3L 4x4 crew cab..Added 275-50 R20's bfg ko2, and a k&n airflow. MPG in town went from 18 to 13, hwy from 23 to 18. Is this normal? (no lift, staying out of throttle also.)

Called Chevy got the "if you alter" blah blah blah but its not like I put on 35's. I figured maybe 1-2mpg loss, just seems excessive.

Will a chip or tuner help bring up mpg? Any help is greatly appreciated!!

[Rawyzf]

275/50 is smaller than stock, did you mean 275/60?

 

That's a pretty big drop in MPGS. I lost a little with going to an AT tire, but gained it back with and Airaid MIT.

 

Sent from Tapatalk App - Samsung S6

[SouthernSilveradoGuy85]

Do you mean K&N air intake kit or K&N drop in factory filter? K&N and any "high performance" air filter will just allow more air which means it will need more fuel so that means the MPGs will drop. By that much though, I don't know.

[Mortis Mango]

sorry 275 55 r20's

[Rawyzf]

That's a big drop, but I get about 16-19 per tank depending on traffic, etc.

 

Stock tires are good for MPGS I have learned.

 

Sent from Tapatalk App - Samsung S6

[Mortis Mango]

installed k&n full airflow kit. They said it should improve mpg maybe .5-1 mpg at chevy.

[Mortis Mango]

Interesting..Any idea if programming/ chip will help?

[Rawyzf]

Tuner will certainty help with MPGs, but not warranty.

 

Sent from Tapatalk App - Samsung S6

[Mortis Mango]

Thank You!

Any Brand tuner that anyone would recommend? Had a Banks on previous diesel, but that is my only experience which chip/tuners.

[Rawyzf]

I'm not tuned, so I'll let someone else chime in there. After my 36k, I'll plan on a local tuner with hp tuner and tune out AFM. If you want a hand held, I've reading Diablo is decent, and even better with a custom tune.

 

Sent from Tapatalk App - Samsung S6

[Mortis Mango]

Thank you

[Rawyzf]

Thank you

I'm still a borderline newbie. I've modified cars for 15yrs, but this is my first 4x4 that I've started tinkering with.

 

Sent from Tapatalk App - Samsung S6

[SouthernSilveradoGuy85]

Can't believe everything. It's simple math and science I guess when it comes to engines. Again I'll say that a high performance air filter no matter the brand (unless it's a cheap normal paper filter that's just sold as high performance on ebay) allows more air to the engine which means the computer will have to add more fuel to adjust for proper air/fuel ratio which of course means the MPGs will drop.

 

Too be honest, nothing aftermarket will make your MPGs better unless you hook a tuner up to it that has an eco mode. When I added the K&N air intake kit on my '98 all it did was give better throttle response, wasn't a huge difference but noticeable. All I have on my '14 is the Airaid MIT tube which keeps the factory filter box and just adds a simple tube from the box to the throttle body. Oh and by the way, when it says that an air intake kit will give a 10 HP gain, that's on a cold run where the engine bay isn't at operating temps. Once you get up to normal temps then it really only adds 2-3 HP. It's just less restrictive which gives you better throttle response, which is why I just got the Airaid MIT tube and not a full intake kit like I did on my '98.

[MMC]

Remember your odometer is no longer reading the distance traveled correctly if the new tires are taller. I doubt that a CAI is going to affect your A/F ratio enough to be the problem.

[Chevor]

I agree with GM.