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I was considering installing a K&N air filter in mt CT....any thoughts?? I've had them in all my previous cars & motorcycles & there is no doubt that they flow more air than stock....my question is does anyone know if it would help -or- hurt the hybrid system?!?!.....I know it's designed to work a specific way & I don't wanna disrupt that. Any thoughts would be much appreciated!! Thanx & God bless to all!
 

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I personally do not use K&N or any another other cotton or even worse foam air filter media. Its been tested many times by experts that paper filters the best. K&N lets in way too many particles and the airflow difference for the same size filter is negligible which means performance difference is even more negligible if any. Not to say they have their purposes like a pro race team where they clean and replace their filters and overhaul their engines after almost every race. For daily drivers especially the CT 1.8L there would be no Pros.
 

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A down side is most tend to over oil these filters and many times the pre oil is too much and isn't good for the mass air flow sensor
 

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I have it on mine. But I replaced mine right off the bat. i haven't had issues with K&N filters before, but you MUST be meticulous with cleaning as previous posters have mentioned, especially with the longer cleaning intervals.
 

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I've used K&N filters on every car and motorcycle I've owned since 84. When my CT comes in at the end of the month it will also wear one. They breath far better than paper, they capture particles far better than paper because they have the oil to stick to. Follow the directions on oiling and cleaning and you will not have a problem. Your car will love you for it and in the long run you will save money in replacement filter cost.
 

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Matt - Never knew you had one in yours, but have you had a chance to see what it's done to your mileage? Sounds like you put it in right away. I had it in my last car, but really don't see the need for it in this car, it's not like I need more air flow in here for more HP, it's not why I bought this car.
 

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Hmmmm. I wonder if that's why my mileage has been a little lower, but consistent with other members' MPG here in trafficky LA/Orange Counties.

I replaced mine at approximately 30 miles or so, so it would be difficult to gauge any increase in MPG. I would probably have to guess little to no measurable change in MPG, since the old filter element was practically brand new and it's not like my new filter increased my HP as far as I can tell.
 

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FYI
K&N Filters Can Cost you Thousands - Technical Discussion Discussions at AutomobileMag.com
FYI for anyone who has a K&N air filter in their car and eventually experiences what seems to be fuel injection problems, hesitation, a mystery transmission problem, acceleration bucking, etc.

After 3 years trying to diagnose my problem in my 2001 Grand Am, it came down to this. The oil that the filter uses ended up fouling the Mass Air Flow Sensor (mass airflow sensor) and was the cause of a 3 year mystery that no mechanic could correctly diagnose. I spent hundreds on tranny work, fuel "fixes", etc. until I finally realized what it was. Yea for me, but a painful learning experience.

To fix it, I removed the air cleaner housing to get to the MAF sensor, took the entire housing apart, and cleaned it with brake cleaner, then let it dry. I then THREW THE K&N AWAY.


How well do K&N air filters work?
The question posed in the title of this post is one that I've seen debated on the 'net since discovering car-related email lists. Fortunately, a Duramax owner tired of the lack of scientific evidence pursued a path of testing that eventually ended with a lab performing the ISO 5011 procedure on a number of replacement air filters. The result was one that many might have concluded on their own - for a given size, a filter's ability to trap dust is inversely proportional to its flow rate. If keeping dust from your engine is the goal, a paper filter such as an AC Delco will provide far superior filtering performance, but you'll pay a price in airflow. If WOT performance is most important, the K&N filter used in this test provided about 50% less restriction to airflow, with the 1.6" of H20 difference in air pressure drop at 350 CFM making for a minimal difference (~0.5%) in power at this flow rate. The K&N and UNI filters were far less efficient at trapping dust, and note that they lose their flow advantage after filtering about 180 grams of dust. There's also the economics of washable cotton filters, with a K&N providing a savings of about $285 over 250,000 miles. All of my vehicles currently run K&N filters, but this test has me re-thinking the use of them on daily drivers.

K&N's response
http://www.knfilters.com/maf/massair.htm



It's up to you. I have yet to hear anything good about using k&N. In order to save money on filter cost one must keep car 250K. How many do this?
 

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I used a K&N drop-in filter in my Infiniti G35 and then went with a Stillen CAI conical intake (same filter media with oil) and never had any issues, 157K miles on the car. I think it's hit or miss and you need to make sure you don't over oil it, as that's what can get the MAF dirty (I cleaned this annually too).

Personally, I don't see any benefit to using a K&N in this car.
 

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hey you guys should remove the SULEV filter, it's an extra filter in the intake filter compartment...
 

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i think it's better then adding a k&n filter, which i will eventually do.
 

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I use the K&N's so I only have to buy one a/f for the life of the car. I doubt they actually boost HP. That's a gimic. But no doubt more efficient flow of air into any engine is better, regardless of whether it's a hybrid, diesel, 2-cycle, or 4-cycle. Never had a problem with MAP sensors getting contaminated.
 

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I noticed the air intake is TINY compared to most cars. Is it restricted for a reason? The hose diameter is SMALL!
 

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I noticed the air intake is TINY compared to most cars. Is it restricted for a reason? The hose diameter is SMALL!
Wow, you weren't kidding - that is small. Considering the diameter of the hose going to the engine and the size of the filter, I wouldn't think a K&N filter would help much at all (except for the reusability aspect).

I wonder how restrictive the secondary filter (SULEV?) is. It seems to be permanently attached to the upper housing of the filter.
 
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