[sum_weirdo]

Just curious. The stock airbox doesn't look too bad as airboxes go and considering $50 filter versus $300 kit....

[digiti]

Well, it's to do with the piping too..

[BullMeister]

Think about it. The K&N doesn't require a tune. A CAI does because it's drawing in so much more air that the engine will run lean without one. A cone filter has several times the intake surface area over the stock airbox little intake hole.

More air and fuel stuffed down it's throat = more power.

Take it a step further and go forced induction with a supercharger. All your doing is stuffing even more air and fuel in which gives you even more power.

[johnr2001]

A CAI does not rquire a tune and in my opinion are not worth the money. I would just do a k&n filter. I have had several cold air intakes on different applications and really dont think they are worth the money.

[A7X1031]

I have a K&N air filter and I think its great just money wise. You can buy a cleaning kit for it for 10 dollars at your local auto store. You never have to replace it either, you clean it every 50k miles. As far as performance goes its like a 2hp difference from what I hear. A CAI like JLT with a tune could give you about 30.

[BullMeister]

Originally Posted by johnr2001

A CAI does not rquire a tune and in my opinion are not worth the money. I would just do a k&n filter. I have had several cold air intakes on different applications and really dont think they are worth the money.

It might not require one on your 2001 Mustang, but the 05 and newer are a different beast. If you don't tune for a real CAI, you will run lean. They are also reusable and you clean them like a K&N.

Here's a dyno pic on a 87 octane bamachips tune (the improvements are much more dramatic if you step up to 91 or 93 octane 'cause you can get timing adjustments then):

[jmmckay]

The airaid for the 05-08 does not require a tune, and does not run "lean"... I'm still considering it, but most guys will say get a cai, get a tune.. i'm gonna go with a K&N for now, maybe a cai with a tune later...JMO..

[mrjimmy]

before I went with the xcharger I had a K&N in the stock air box.That was the first thing I did when I got my car,change the air filter. I noticed an immediate improvement,butt dyno says yes.Most CAI's require a tune to get the most out of the increased airflow,some dont.You would be wasting your money if didnt get the complete set,CAI and Tuner..IMHO

[BullMeister]

Originally Posted by jmmckay

The airaid for the 05-08 does not require a tune, and does not run "lean"... I'm still considering it, but most guys will say get a cai, get a tune.. i'm gonna go with a K&N for now, maybe a cai with a tune later...JMO..

There are some out there that don't require a tune but that's because they restrict the airflow down to the point where it doesn't require one. They still give you more air than the stock airbox, but not as much as a true CAI.

I think the demolet intake is a good example (hope I'm thinking of the right one). If you want to run it without a tune, you have to insert a baffle into it to restrict airflow. Once you get a tune for the CAI, you can remove it and get the full performance out of it.

[sum_weirdo]

Well I already have a Hypertech programmer so it's a bit late to get a CAI/Tuner combo. The Hypertech is supposedly designed to accept minor mods like CAI and exhaust but it's a more universal tune I guess. I'll have to research it some more to decide.

[burnrubber4.0]

diff = night and day to me....the k&n does help, but not like a CAI and a tune

[FYouGitive]

There is a learned gentleman on Usenet group rec.autos. .ford.mustang who is making cogent arguments that a K&N is no better than an original pleated paper Ford air filter in all conditions other than WOT. He backs it with citations and examples.

I like the K&N (been using them for decades) because of its economy. Not fuel economy, but replacement cost economy. It costs a lot less over the life of a car than the paper ones.

I wonder if running without an air filter for short periods (autocrosses, drag racing events) would yield more power, or would it overwhelm the computer?

[wnewport]

I remember reading that ANYTHING in the intake upstream of the throttle really matters the most at wide open throttle, because at part throttle the biggest restriction to flow is the throttle itself! Exhaust on the other hand provides a reduction in backpressure across the throttle and rpm bands. (No BS about the engine requiring backpressure please- that belies a misunderstanding of how an internal combustion engine works.)

[BullMeister]

Here's a decent article (with pictures!) on how backpressure works in 4 stroke engines.

Flowmaster, Inc.