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K&N Filters and Cold Air intakes - worth it?

greywolf2112

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greywolf2112 Enthusiast

greywolf2112

Posted
Posted

OK, just got the 2004 Suburban with the 8.1L engine. My dad has an RV with the same engine and told me that installing a K&N filter to replace his regular filter gained him about 2 MPG.

 

Now, the filter is about $50. A cold air intake is about $250.

 

Would either gain me some MPG? I drive very conservatively (under 70 - most of the time on the interstate I am doing 65).

 

Would the extra $200 for the cold air intake give me enough of a savings to justify it over the $50 filter, and would the $50 filter be worth it over just a regular old air filter?

 

Thanks for the help!

ZZ327 Senior Enthusiast

ZZ327

Posted
Posted

just the filter is worth it. what they have now is basically cold air intake. You could build your own piping out of black PVC and save 230 bucks.

Elwood 2000 Senior Enthusiast

Elwood 2000

Posted
Posted

I have an AEM Brute Force intake systam and I do like it. I feel that it did gain me a little bit of power, although I don't have any dyno sheets to prove it. It is a bit noisy though. If you are going to use this rig to travel in, long hours of driving, I would keep things quiet.

 

I have read that tru-flow drop in filters work very well.

Dragon Slayer Enthusiast

Dragon Slayer

Posted
Posted
OK, just got the 2004 Suburban with the 8.1L engine.  My dad has an RV with the same engine and told me that installing a K&N filter to replace his regular filter gained him about 2 MPG.

 

Now, the filter is about $50.  A cold air intake is about $250.

 

Would either gain me some MPG?  I drive very conservatively (under 70 - most of the time on the interstate I am doing 65). 

 

Would the extra $200 for the cold air intake give me enough of a savings to justify it over the $50 filter, and would the $50 filter be worth it over just a regular old air filter?

 

Thanks for the help!

 

 

 

 

 

I bought a drop in K&N filter at Wal-Mart for $39

07SilveradoClassic Enthusiast

07SilveradoClassic

Posted
Posted

Since I am cheap (and having spent hours researching the various CAI systems with no concrete proof of improvements) , on my stock air cleaner box I took my die grinder and opened up (port matched) the plastic air box inlet horn to the fender which had what looked to me to be a pretty good restriction, I also sanded the airbox to MAF area to remove/smooth flashing. I inspected the air tube to the intake and it was surprisingly smooth and left that alone. End result is the fact that I did not spend any money and call me crazy but, I have the same psychological feeling of a horsepower and sound improvement.

 

HA ( I am also guilty back in the late 70's of flipping the air cleaner lid on my 75 Cutlass to get the Quadrajet howl) now tell me none of you ever did that one!!!! :cool:

keebler Enthusiast

keebler

Posted
Posted
Since I am cheap (and having spent hours researching the various CAI systems with no concrete proof of improvements) , on my stock air cleaner box I took my die grinder and opened up (port matched) the plastic air box inlet horn to the fender which had what looked to me to be a pretty good restriction, I also sanded the airbox to MAF area to remove/smooth flashing. I inspected the air tube to the intake and it was surprisingly smooth and left that alone. End result is the fact that I did not spend any money and call me crazy but, I have the same psychological feeling of a horsepower and sound improvement.

 

HA ( I am also guilty back in the late 70's of flipping the air cleaner lid on my 75 Cutlass to get the Quadrajet howl) now tell me none of you ever did that one!!!!  :cool:

 

 

 

 

My thinking is more like your's except I'm not enough of a believer to actually modify anything. I can't get past the reasoning below-- maybe someone here can change my mind...

 

Better fuel economy would require using LESS fuel under any given set of circumstances, right?

 

The truck directly measures the volume of air drawn in to the engine with the MAF sensor. If it doesn't already know from the MAF senser, there's a IAT sensor to measure the temperature of the air so it can calculate its density. With this information it adjusts injector pulse-width and injects enough fuel to match the ideal 14.7:1 ratio of air and fuel by mass. Even if you can modify the intake and make it calculate wrong and inject less, the feedback from the O2 sensor allows it to fine-tune everything back in to balance anyway.

 

How then can ANY intake modification change the amount of fuel used?

 

 

If the answer is "less restriction", then that's confusing too. I don't care what you do to the intake, nothing has more restriction than the throttle plate itself -- unless it's WIDE OPEN. I don't know about you, but I am SURE I won't get good fuel economy if I drive around with the accelerator floored most of the time. I do believe that having less restriction can improve the volume of air the engine intakes at WOT, and this will deliver more power. But seriously, how much time do you spend with the pedal mashed into the carpeting? 10% of the time? 1% of the time? For myself, it's so infrequent that I can't remember the last time I floored it.

 

Why then does it make sense to improve how well the truck breathes if you can't ever change the air-fuel ratio and you can only benefit from the extra air volume when it's floored?

 

How much money does it make sense to spend on a modification that improves the performance only during the 2% of the time that you drive with the accelerator floored?

 

Someone PLEASE set me straight -- I want to "believe" too. There's too many people who believe in this stuff for me to be correct and everyone else to be wrong!

cmoore74 Enthusiast

cmoore74

Posted
Posted

Honestly I think it depends on how challenged your vehicle is and how often (i.e. are you towing a relatively heavy load for your vehicle very often).

 

My last truck was a 2000 S-10 with the 4.3L. I was using this truck to tow a 3500 lb. boat + occupants + gear. This was a lot for this truck. A "cold air" intake helped quite a bit with towing. I had more power for hill climbing (a lot of those from my house to the ramp) and when not towing it gave a big improvement in throttle response. The only increase in MPG was when towing and it was about 1 MPG, nothing when not towing. This is all based on back-to-back towing of the same weight on the same route at the same speed with the stock filter and intake set-up and a K&N FIPK2.

 

I put "cold air" in quotes because I agree they are not a cold air intake at all, but they do result in less restriction due to reduced losses coming into the air box, increased flow through the filter, and reduced losses through the tube from the filter to the throttle body. The less loss the less the engine has to work to draw in the air.

 

Another story, a buddy of mine has a 2001 3/4 ton duramax which he tows a 5th wheel camper at about 12000 lbs fully loaded. He got back from a 3 month trip across country including a lot of driving through the mountains out west. When he got back he checked his stock air filter. The engine was so starved for air it actually flattened out the pleats. He's now looking at intake systems for his DuraMax.

 

I say it depends on how challenged your engine is relative to the load you are towing as to whether or not you will observe a difference.

 

A lot of people here aren't crazy about K&N's due to the stories of bad MAF's due to over-oiled filters, but I've never had a problem. I was concerned over the actual filtration ability of the K&N (especially with all the fine sand blowing around during and after a New England winter) so I decided to give AirAid a try on the new truck. We'll see what the oil analysis says for silicates after this winter as to whether the filter is doing its job.

 

By the way, if you haven't observed this already, this is typically a very heated topic with opinions all over the place.

Mr. Smith Enthusiast

Mr. Smith

Posted
Posted

Unless you have actual dyno results proving an actual power increase the SOTP meter is useless. This has been beat to death more than once. Waste of money sure...Who am I to say don't throw your money down the crapper....

 

CAI & Cat-backs... These were marketed well and everyone thinks they are so wonderful. Cost vs hp gained isn't worth it.

 

SOTP-Seat of the pants.

C & A s Dad Senior Enthusiast

C & A s Dad

Posted
Posted

 

By the way, if you haven't observed this already, this is typically a very heated topic with opinions all over the place.

 

 

 

 

 

It seems like just about EVERY topic here gets heated :D

 

 

 

 

 

 

This is why I am always very careful to say things like "In my opinion" or "at least for my truck" or "this is what It has done for me". It comes down to you deciding to spend your own money on your own truck.

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