The Diesel Stop banner

1 - 7 of 7 Posts

·
Registered
Joined
·
22 Posts
Discussion Starter #1
I have a 2015 F350 diesel that I hate the MPG. around town 12mpg, on straight highway 14mpg. and pulling my 15K RV about 8.5mpg.


So, I finally put a $75 K&N air filter in and suddenly it has increased my mileage by 1-2mpg? really????? pulling at 65 mph it was rated at 9.5mpg....ummm. around town--just short time---15mpg??????ummm:surprise:



I guess we'll see.


My old 2006 chevy diesel always got much better mpgs....oh well, we'll see.


go K&N
 

·
Registered
Joined
·
2,501 Posts
Not to be disrespectful, but many do not recommend the K&N style filters when the engine has a turbo. The oiled screen tends to allow some silica to pass and then possible damage over time to the turbo vanes.

Does this filter setup still use the Ford stock air box? If so, do you still use the foam pre-filter? If you use the foam pre-filter, you might be ok.
 

·
Registered
Joined
·
4,611 Posts
Is this hand calculated or off a readout.
DENNY
 

·
Premium Member
Joined
·
3,805 Posts
If the same factory airbox is used then the equation is:
Better filtering = more restrictive.
Less restrictive = poorer filtration.

Individual preference on priority.
 

·
Registered
Joined
·
22 Posts
Discussion Starter #5
update. the k&n filter seems to have increased my pulling to about 10mpg.....about time

as for just driving on highway, still around 14mpg. around town 12+mpg. I only dream of those mpgs people talk about that are around 19-20mpg.....

oh well, I didn't need the $75 I spent on the k&n filter anyway.

this is just the stock air system and I just changed out the filter, it is a non oiled filter.
 

·
Registered
Joined
·
581 Posts
Personally I don't see how it's possible for an air filter to improve fuel economy on a vehicle like this. Back in the carburetor days when a restricted filter would have a choking effect on an engine, yeah but with an engine that is measuring the volume of air going in then metering the proper amount of fuel, no. If anything a restricted air filter will limit the total volume of air available and should improve economy under wide open acceleration. Some things that will make a difference that may go unnoticed are the quality of fuel, summer or winter blend of fuel, driving habits and conditions. Short trips will kill fuel economy especially on a heavy truck. You can't rely on the DIC for accurate or consistent fuel economy numbers. Mine will vary anywhere from .5 to 1.5 difference in actual hand calculated. Fuel from different stations in the same area will yield different fuel economy. I found my truck gets better MPG from fuel I buy outside of my home state.
 

·
Premium Member
Joined
·
4,074 Posts
The motor is nothing more than a big air pump. The easier the path/flow of air into and out of the motor the better.

Go buy a really thick milkshake. Use one of those cocktail straws to try to drink the milkshake. Then go get those huge MC'D straws......

The flow thru the filter into the turbo is better with the K&N but the filter brand has had bad past history when used with turbos.

yeah but with an engine that is measuring the volume of air going in then metering the proper amount of fuel, no. If anything a restricted air filter will limit the total volume of air available and should improve economy under wide open acceleration.
Hence you would have ****ty performance to boot....not what people want at WOT right?

Since I have tracked my MPGs for over 135k now I can say there's a significant difference in the dash display, as well as the odometer showing miles driven. In the end the numbers don't lie. Even with some of the factors I listed the MPGs are only about .5MPG off from my hand calculations and using my standalone GPS miles driven.

The odometer seems to be 1-3% off on the miles when compared to GPS miles driven. That 1% number gives better results cause I'm running a size over stock tires. So when running factory tires it's in the 3% difference area for miles driven when comparing the dash odometer and standalone GPS.
 
1 - 7 of 7 Posts
Top