New Air Filter
 

Is it worth while replacing a stock air filter on a stock engine with a K&N air filter. Will you actually gain any HP, feel and difference, or reduce your 0 to 60 times?

It won't net a whole lot of power, but so far, the best results in terms of intake have been seen with the stock intake and a K&N (or the likes) filter.

Replacing the filter with an aftermarket drop in filter may get you a few extra HP, but it's nothing you'll be able to feel. 5 HP difference at 7000 RPM in a 2900 lb. car just isn't going to be noticeable. It may change the intake sound and make you think it "feels" faster though. I bought mine mainly so I can wash and reuse it.

That's correct, but I was just saying that you won't get any more by going with a whole intake over just dropping in a filter. Only reason to get a full intake is for looks.

Now that's interesting. I would have thought a full cold air intake would do much better.

the factory with its millions of dollars is pretty good at designing intakes these days. Scion Tc's where the same. Stock intake beat aftermarket ones everytime. On a side note if you put too much oil on a K&n it can get on the maf and cause problems. More common in the GM vortec world though. But it is important to note a paper filter will always do better at filtering out water when compared to a oiled cotton filter.

Well when the stock design is already a well designed Cold Air Intake system...an aftermarket one is a huge waste of money.

There was a tiny increase in throttle response with the K&N. Secondary benefit of K&N (an other) drop in air-filters are they are easier to get in and out of the airbox than the stupid stock filter....hate the double stack/offset stock filter design that makes it a royal PAIN to get in or out of the housing with a silicone intake tract! Literally took me nearly a half hour to get the factory filter in the first time when I replaced the intake track with a smoother silicone section before I was able to source a K&N filter...

I suggest skipping the K&N filter and going with a non-oiled filter such as Cosworth or Blitz. As many have said, the oil in the K&N could cause MAF fouling issues. I have a Blitz dry filter installed in mine. There is an increase in throttle response and a rather noticeable change in the induction noise. Power-wise, it feels as if it's gained a little more power in the top end. Doesn't feel like it's being 'choked' at high RPMs. However, it will lean out the fuel/air mixture slightly. The stock ECU is notoriously difficult to tune and difficult to accept mods, especially with shitty CA 91 fuel. It may eventually 'learn' the lean-ness of the A/F ratio and 'tune' out any gains you may have had when you first installed the filter to bring the A/F ratio to safe levels to prevent knock. Rule of thumb: Anything dealing with the intake requires a tune to get the most out of it. Just installing a cold air intake will may gain you a few HP for a couple of days. Until the ECU 'learns' it. Then you're back to stock power.

Check out this article:

http://www.motoiq.com/MagazineArticl...strations.aspx

And that's just on the exhaust side. Can't imagine the how much of a PITA it would be to tune one of these with an aftermarket intake using CA 91 fuel.

Hmmm........If I lived in a potentially dusty area like Indio ...... I'd leave the stock filter in place.

I live in Western Washington, where we don't have much dust, just rocks and rain and I put in a K&N oiled filter.

Any difference I sinse I think is in my head .... ??


humfrz

agree with most of above post

What happens on 91 usa fuel is the engine knocks then the ecu to "save" the engine reduces a parameter called the IAM (Ignition advance multiplier) which reduces the timing advance applied across the entire RPM/load range and hence reduction in power. Generally this knock is most prevalent in the 1500 to 3500 rpm range but the result will be advance retard over the entire rpm range.

The engine is designed to run on 93 plus octane it will run on lower octane fuel but at reduced power. On higher octane fuel above 93 (once IAM=1) its max value then no more power is produced unless you now alter the "tune" of the engine to take advantage of the extra octane rating of the fuel, but you will get increased knock resistance for hard or track driving especially in hot weather.

see here for more info (our aussie fuel is not quite as good as 93 usa ,our 98 RON)
http://www.ft86club.com/forums/showthread.php?t=61820

For intakes yes they generally will upset MAF scaling and some are not to good may produce turbulent flow arround MAF (the stock intake has an "air straightner" inside before MAF) which makes tuning difficult, the stock intake is quite adequate for NA cars ,but just a filter will be fine as it does not change the diameter of the tube the maf sits in or the flow pattern around the MAF (Mass air flow sensor) you might pick up a couple of HP at the expense of poorer filtration.

The ecu will attempt to correct for afr (MAF scale problems) over time, usually fairly short and if the intake caused a leaner/richer AFR than target (in the fueling tables) the ecu will adjust fuel trims to compensate often negating the apparent HP increase at the initial installation or ecu reset. this will generally occur in minutes of driving at the effected rpm/load range.

see here
http://www.ft86club.com/forums/showthread.php?t=64790


generally an aftermarket intake will only produce a few hp gain at high rpm after a tune (on a naturally aspirated car)you can pick up most of that with just a drop in filter, but most aftermarket intakes and aftermarket filters will not filter as well in adverse conditions as a stock filter.

Sounds like a K&N might cause more problems than benefits with poor quality gas.
Does anyone use an octane booster? I have used this in my other car
http://www.motorsports.mybigcommerce.com/single-can/
I use one quart to 20 gallons of gas. This takes my 91 to 93
Would something like this be good to use with 91 gas?

Problem with that logic is that cost of manufacturing always plays a huge part in manufacturing. So they would choose a simpler, cheaper design if it saved $100/car and only lost, say, 5 hp.


I have run a K&N filter for more than 15k miles without any issues, including a re-oiling. I noticed a little extra on the butt dyno, and so have many others, but take that for what it is. Use an MAF cleaner at each re-oil and you'll be fine. I'll probably use the MAF cleaner again now that the re-oil has a few thousand miles through it.

Also, this has been talked about ad nauseam on here already.

I just installed the injen cold air intake system. It's worth the price, I paid $270 for mine, they're now listed around $250 on amazon. Just google: Injen SP1230WB

10hp gains to the wheels according to dyno's posted on this forum. It sounds nice when you step on it, and quite when you want it to be.

I installed the K&N air filter a few weeks ago, I noticed that the engine sounds alot quieter when idling. This is normal I suppose?