aftermarket filter

[MAKG]

Your stock intake is not the smallest restriction.

See if you can ask a machine shop (or auto tech school) to show you a head. The smallest restriction is in the intake runners, right behind the valves. Every head has a venturi there.

Removing ANY other restriction is putting a bigger funnel into the same garden hose and expecting more water to come through.

And you do NOT want to remove this restriction. It gets air past the valves quickly; if you don't, your head will be a flaming brick of s**t, and will lose performance across the board (including peak power).

 

[JohnPi]

As most of the stories are, my experience is by definition annecdotal.

When I bought my truck in '99 with 89,000 miles, it's paper filter was clogged beyond belief, making the engine choke out around 3,000 RPM's. I replaced the filter with a K&N, and was able to get proper breathing at all engine ranges. I now have 247,000 miles on the truck with the same K&N, and I've never had to clean the MAF sensor. I've cleaned and oiled the K&N about once every 50,000 miles. I've never experienced the bogging that the truck had when I bought it.

Now, admittedly, when I bought it I was looking to get HP gains, but as I got older I realized that wasn't really happening. Now, from a more pragmatic standpoint, I keep it because I don't have to buy a paper filter at $10/ea. every 6 months. I bought the oiling and cleaning kit once, and now I use Simple Green to clean the filter, and the oil lasts a long time. I don't worry about Environmental Fallout from the cleaning, because the Simple Green is biodegradable.

So, I think I've saved myself a ton of money from my initial investment, and I don't have the efficiency issues I had with a negleted paper filter. The filter was originally around $40, which would have bought 4 paper filters, which would have lasted 2 years, and I've had the truck now 9 years. So, I've had 7 years of "free" operation (7 years after the K&N was amoritized). I have a K&N on all three vehicles in the fleet, and have not experienced one problem.

And I wouldn't have a problem recommending one to anyone, with the caveat that they shouldn't really expect HP gains, but they will save money in the long run.

 

[85_Ranger4x4]

Your stock intake is not the smallest restriction.

See if you can ask a machine shop (or auto tech school) to show you a head. The smallest restriction is in the intake runners, right behind the valves. Every head has a venturi there.

Removing ANY other restriction is putting a bigger funnel into the same garden hose and expecting more water to come through.

And you do NOT want to remove this restriction. It gets air past the valves quickly; if you don't, your head will be a flaming brick of s**t, and will lose performance across the board (including peak power).

I was bored one night and did a little experimenting. Like I said I didn't really notice much change one way or the other, milage is the same, it still tows just as well as it ever has so I am fairly sure if I lost power it wasn't major.

You do have to reset the PCM or it will not run right (like with any other intake), which tells me something is different than it was stock. It would eventually adapt to it on its own but it is easier to start with a clean slate.

I know the there are more restrictions than that goofy little part I swapped out, but it was dirt cheap, easy to do, easily reversable and killed a evening.

 

[shadetree]

Your stock intake is not the smallest restriction.

See if you can ask a machine shop (or auto tech school) to show you a head. The smallest restriction is in the intake runners, right behind the valves. Every head has a venturi there.

Removing ANY other restriction is putting a bigger funnel into the same garden hose and expecting more water to come through.

And you do NOT want to remove this restriction. It gets air past the valves quickly; if you don't, your head will be a flaming brick of s**t, and will lose performance across the board (including peak power).

It is evident you have never ported a head before. In fact, this entire thread has more mis-information in it than in any single thread I have seen in quite a while. shady

 

[JohnnyU]

Actually flow velocity is VERY important to head performance.....

 

[Black_Splash]

Thanks guys. This is the info I was looking for, I can now make an informed decision. I assume the MPG gain is all BS also?

 

[lil red]

if you dont slam on the gas ypu should see a little gain, not much
it is possible to get a little bit, but nothing to call mom over

i just liked the lowend the k&n and the 40 series did to my friends bronco

 

[kunar]

im suprised nobody has posted this link yet

http://www.bobistheoilguy.com/airfilter/airtest1.htm

he tested a few different filters for flow and filtering ability. kinda neat to skim through

 

[Will]

Velocity is everything because it takes time to fill a cylinder at you don't have a lot of it. You cut airspeed when you make the hole bigger and you might not have time for your high-volume, high inertia air mass to get its ass into the chamber.

I've seen a lot of people port heads and create stinkers. When people actually used stock motors to race with in NASCAR and ProStock, they massacred truckloads of factory castings before they got ones that would work. It wasn't making it larger that did the trick in many cases--it was moving the port to straighten the path into the head and removing turbulence.

 

[Bob Ayers]

Velocity is everything because it takes time to fill a cylinder at you don't have a lot of it. You cut airspeed when you make the hole bigger and you might not have time for your high-volume, high inertia air mass to get its ass into the chamber.

I've seen a lot of people port heads and create stinkers. When people actually used stock motors to race with in NASCAR and ProStock, they massacred truckloads of factory castings before they got ones that would work. It wasn't making it larger that did the trick in many cases--it was moving the port to straighten the path into the head and removing turbulence.

I agree, and don't forget about the accuracy of the MAF sensor. It is designed for a certain air velocity, and going to a larger diameter intake
lowers the air velocity, which makes the MAF sensor mesure less air than is actually flowing. This will cause a lean condition.

 

[shadetree]

The intake works just like the exhaust in relation to the physics that effect flow. The system needs to work as a whole. Doing one without the other can offer some benefits, but to get full benefits of the system, it needs to be "tuned" together.

If you are going to go to the trouble of porting, polishing, enlarging the ports to increase flow, port matching, etc., you would not be putting the stock MAF(if it has MAF) back on the engine. Defeats the purpose of the work.

If it is just bowl clean-up, reducing restrictions, cc polish, and port matching, the MAF will adjust accordingly.shady

 

[Bob Ayers]

If it is just bowl clean-up, reducing restrictions, cc polish, and port matching, the MAF will adjust accordingly.shady

The MAF will not adjust to a larger diameter intake with reduced air flow velocity. Once in closed loop, the O2 sensors will try and make the A/F ratio correct, but it will still probably throw lean codes.

 

[shadetree]

The MAF will not adjust to a larger diameter intake with reduced air flow velocity. Once in closed loop, the O2 sensors will try and make the A/F ratio correct, but it will still probably throw lean codes.

Please re-read the second paragraph of my post. Also, the operative word in your post above is "probably." My question would be "how much reduction in airflow would be necessary to require retuning the system?" Port work on later stock heads doesn't effect that much change. Some earlier heads could really be opened up, however ther were not used with EFI systems unless they were aftermarket, or modifications to the stock computer.

A MAF measures mass, not volume, so it is very lenient in its operation. Air density due to temperature, humidity, etc., changes the mass, and the sensor can adjust accordingly.

In many cases, the MAF itself is the restriction, and anything you do to the airflow system after this restriction would be somewhat nullified without a change to a different device.shady

 

[TwoWhels]

LOL LOL i just read through this thread Just wanted to add....

I found something new ...
Fram Washable air filter. On my 86 2.9 pn was WA3660

Been on for about 3000 miles

No oiling just wash and about $14.00


Anyone else see em?

 

[Bob Ayers]

A MAF measures mass, not volume, so it is very lenient in its operation. Air density due to temperature, humidity, etc., changes the mass, and the sensor can adjust accordingly.

WRONG Shady, if you decrease the air velocity across the MAF sensor, then the MAF element will not change resistance accordingly for the same air flow. There is a IAT for determining the temp of the air in the intake.

And Shady, I said VELOCITY, NOT VOLUME, but since you didn't know it, air volume and mass are directly related:

http://www.grc.nasa.gov/WWW/K-12/airplane/airprop.html