How much horsepower will a drop in K&N filter give me?


Asked by Apr 15, 2008 at 12:43 PM about the 2008 Nissan Altima Coupe 3.5 SE

Question type: Car Customization

23 Answers


I put a K&N on my truck I also removed the screen before the air filter box and don't forget to remove the positive cable for 5-mins so the computer can reset and re-learn the new air-fuel mixture. You will hear and feel the difference. Remember more air means more gas and less miles per gallon! (OUCH!)

2 people found this helpful.

first of all you wont notice much if any difference; seat of pants difference takes more than a 2hp increase. secondlyin response to the guy above dont you think engineers spend countless hours do making sure that the stock paper element isnt restrictive and how will there be more sound? thirdly it will use the same or less amount of gas until you floor it all the time naturally the milage is most dependant on the driver

4 people found this helpful.

yea more air means more gas, but your only going to get more air if your accelerating harder. The K&N filters simply make air flow less restrictive, and thus more efficient. You will see nothing but improvement. However, k&n gets expensive. A k&n for my car costs about 180 plus shipping, and i got one off ebay, just a s good, for 70 shipped

1 people found this helpful.

1 - 3 hp max, and it does flow in lots more air, but it also flows in lots more particles. Stick with the factory style air filters, unless you're getting a decent WAI or CAI.

4 people found this helpful.

Paper filters are not 100% resistant to dirt and particles.

1 people found this helpful.

The industry standard is 96% and K&N meets those requirements. I doubt the validity of the these independent tests. Botton line, I installed one on my GTI and there is about a 3% increase in hp BUT the throttle is more responsive and I actually can hear more of a growl!

6 people found this helpful.

regarding KN performance I do notice a small amount. I drive often and lots of miles per year. the last KN filter I used for over 100,000 miles with no damage to my engine in all weathers so negligible particles do not get through and the bonus is the durability of the filters, sure they cost more but you never have to replace them (unless damaged). I just remove the KN, wash it out every 50,000 miles or so and coat in a thin layer of engine oil then replace. just remember to tell your garage not to replace the air filter when you service your car. works out cheaper than changing the paper ones every 15,000 to 30,000 or so. iv used KN filters for years on many cars and never had a problem. and no dealer or mechanic has never told me I shouldn't be using them.

3 people found this helpful.

Bought my 2006 mustang gt new in Sept. 2005. Replaced stock air filter with K&N drop in filter and noticed an immediate performance boost. 0-60 times 2/10's better. 5.1 to 4.9 (auto trans and 255/50's). Best thing is increased throttle response. Stomp it with K&N and paint long black burnout lines without power braking.The car could not do this with stock filter. Same performance now with 30k miles and have not touched the filter.

1 people found this helpful.

1-3 horsepower, which is about what you would see in a temperature drop of 5 degrees

2 people found this helpful.

Without changing driving habits I got a 1mpg increase. Hard to tell if there is much of a difference in HP. My truck (F150 3.5L Ecoboost) has always pulled and accelerated like a banshee. With that said I really got because of money savings over the life of my truck not having to buy air filter after air filter.


Just the filter won't gain you much if anything but if you go with the upgraded K&N intake system you probably will gain several HP especially if you upgrade the exhaust too. I think K&N can back up their claims with dyno data. Don't use engine oil, use the correct air filter oil!

I heard from some folks who have a K&N Air filter that it ranges from 4 to7%. I'm guessing with my 2012 Camaro 2SS with 400hp without the K&N Air filter (Auto) that it will range from 416 to 428HP new HP ratings. 400HP x 4% equals at least 416HP. your thoughts?


gives increased airflow and better throttle response if you have a turboed car youll hear the difference in the sound of the turbo spool




All these people claiming they've gained 1-3 hp are total freaking idiots!!!! How do they know, because they "THINK" they can feel the difference when they mash the gas pedal down???? I don't hardly think so!!!! In a car you will NOT notice a 1-3 HP gain!! 1-3 hp gain is barely if at all noticeable on a 500 lb motorcycle let a lone a 3500-4000 lb car!!!! The only way to tell if you've gained any hp is to have your car PROFESSIONALLY run on a dyno machine and those numbers will tell you that hp gains with a K&N are minimal at best!!!!!!!!!!! And even if you did run your car on a dyno and gained 1-3 hp, those gains could be attributed to a number of things besides the air filter like air temp at the time of the dyno run, humidity at that time, barometric pressure, tire pressure at the time, fuel etc etc etc. 1-3 hp can be had or lost from day to day depending on those factors and those factors alone and not because of putting in a K&N air filter.

2 people found this helpful.

I put a K&N on my 05 Stang...great throttle response. plus i changed out the stock headers for BBks and 40 series dual flow masters with an x pipe. car runs mean and sexy.


There is definitaly some improvement with the K&N air filter. I don't think it right for Mr Tom there to call people idiots just because they feel some slight power improvement. It is proven on dyno results that in using a K&N filter does help improve slight hp. Either it be 3 ho or 5 hp. Bottom line you are gaining and are not going the opposite direction. Then there are savings in usung one filter instead of replacing it every so often. You are also contributing to the environment. I am happy with my K&N air filter and do also feel the car respobding better. What do i drive? 124 Abarth Spider twin turbo.

1 people found this helpful.

I have added this photo on my fuel consumption. The driving conditions were a nice sunny mild day and temperature around 28c. My car also just had a service a few days ago, so tyres e.t.c are what it should be. The Car is a 124 Abarth Spider 170hp 2017 model. My drive on the day was a leasure drive but giving my Roadster stick every so often as well. You should find just like i did that fuel consumption are nothing to be concerned about witg a K&N filter unless one has a lead foot most the time. I am pretty happy in the results my car shows ne on the display.

1 people found this helpful.

The regular drop in filter will give you about 80 horsepower or so. After I installed one I was able to do 200 foot long burnouts in my 94 civic automatic. Yesterday I raced a hellcat and almost won. Also, it sounds so sweet now, my car sounds like a fighter jet now

1 people found this helpful.

Thanks ABARTH. I just bought one Friday. Pretty peppy as it is but I always add a K&N

1 people found this helpful.

Hahaha is this site called car gurus or car gullables? K&N filters will do nothing for your engine except lessen its life time. The guy who called everyone idiots was absolutely right. Don’t want to be an idiot, open your eyes, do some research and apply some goddamn common sense.


Good on you! You will always have some critic but from personal experience all positive with the K&N filter.


Have used K&Ns on two Audi V8s as well as a Yamaha FJR 1300. Love them. Barely noticeable snappiness to acceleration. Frankly, not sure if one gets a measurable power/torque increase, but certainly the airflow is better/less restricted, and that can only be good. Have over 100k on one of the Audi filters and have used the proper K&N "recharge" system to clean and oil the filter. Love 'em.

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