This is a question in reference to my truck (signature - 89 F150 300/6 Manual).

Airbox on this thing is weird. Oblong intake..going to circular again and then oblong into the left side of the box. Flat panel filter and then the twin circular holes on the left side again. This doesn't strike me as a very efficient setup. It would seem all the air wants to go in the left side of the filter. What I was curious about was enlarging my intake hole...and taking the box and plugging all the holes that are there currently. After this...cut out holes to attack the twin intake hoses directly to the box on its top (same side as it pulls air from now) so that it is centered and it will be pulling air from all across the filter. Then...repeat this same thing on the bottom. Run a larger pipe or hose from the enlarged opening (sealed up) and then cut a hole in the box to run the tube into so that the air is being sent into the panel filter more centered..and hopefully it would use more of the filter overall. Does this sound alright, or stupid? I'd make sure everything was sealed, all the new holes all the old holes. I just don't like the design it has right now. Makes me think that one side (left) would get dirty fast and then hurt power.

Another thing. The crankcase outlet runs a line over to my filter housing and puts the air into the right side of the box...and on my old filter that I changed two days ago, it was all oily over there. Can I just leave the line open and have it put out into the engine compartment?

My truck was getting terrible mileage - like between 9 and 11 mpg, before I changed my filter. The old filter was terrible. You could beat it against the bumper and dust would go everywhere. It was visibly filthy and everything - looked well beyond replacement cycle. Would this have been somewhat responsible for my mileage troubles, maybe? Not solely..but somewhat? Guy at Orielly's said so. Btw..old one was Fram-crap new one is Motorcraft =).

 

You got me confused with all that cutting and relocating. If you got a few bucks and want increased HP at the same time, here's something a little easier.
http://store.summitracing.com/partde...2D2503&view=33

 

Thats exactly it, I don't have the extra bucks to throw around.

Ok. Currently air comes in the left side on the bottom, and then goes out on the left side on the top. I'm wanting to basically turn the box on its side so that the portion pointing to the front of the truck would be pointing up. This would make the intake-side of the filter face the engine, and the filter side face the air. Now...holes on the sides would be plugged and sealed completely. My truck has twin air hoses that go into the intake (Don't understand it...do I have twin TB's?), and so I would simply cut out the holes for the two tubes and then plug them into it, then glue and seal the hole. Following suit, I'd run a tub from where the air is currently brought in (under the battery almost) and bring it into the air box in about the center of the bottom. Again, sealing up the hole. This would make it a tube - box - filter flat in the way - box - twin air tubes - intake manifold. I hope that maybe explains it a bit better. It seems like it wouldn't be too difficult as long as I was careful.

Am I just being dumb, and should I just leave the stock system as it is?

 

No sounds good. Just try to keep it as short as possible. The longer the system, the more time the air gets to heat up. The colder, the denser. As far as the twin T/B, yes,but in on piece, later Ford went to single large.

 

If I decide to do this..I'll probably go to a junk yard first and pick up an old airbox assembly from a friend of mine...that way if I screw up then I'll be ok still.

As far as the question in my original post about the crankcase filter as well as just the mpg deficit in relation to the appearance of my air filter, what's your opinion on those?

 

As far as the crankcase fitler goes, get a longer hose and run it down to just below the frame with the filter on the end or something like a piece of Chore Girl(Plastic Brillo) in the end of to keep from being plugged up. That way it won't make a mess of the engine compartment.

Dirty airfilter will definitely cause poor MPG. You might want to invest in a K&N filter for the box when you get some extra cash. There about $40 for your year. Reuseable and allows more airflow than stock type paper filters.

 

You can make your own K&N FIPK for your truck. No need to spend $200 or more on it. Just buy the filter that goes with the kit and get two 3" tubes to connect the air hoses to the filter. A buddy of mine made a how-to on this setup. Shouldn't cost you more than $60 and works great!

 

FWIW, redirecting the airflow through that box is not likely to improve the performance of your engine. That filter has more than enough surface-area to feed even a modified I-6 (just for comparison, the same airbox was used for the 460 engine), and the pressure difference across that filter surface is going to be minimal, so relocating the attachment-points for the hoses won't make much, if any, difference.

In regard to your breather vent filter, all that oil will just go all over your engine-compartment if you disconnect it; besides, it's supposed to be an air INLET, to provide fresh air to your crankcase to be drawn out through the PCV valve. Your PCV valve could be clogged or stuck shut if you're getting oil in your aircleaner housing. Of course, just leaving it open to the engine-compartment will also draw in dirty air from inside there, when it isn't blowing oil-vapor everywhere.

 

Bob is right about the PCV filter.

And the box setup is very poorly thought up in my opinion. Especially since mine is broke all to crap. Then again, the previous owner of my truck was a wanabee mechanic.
routeing the filter properly in the engine compartment, instead of hanging it to the ground would be best. If the filter stays above the engine, its more likely to get air, isntead of leak out oil. =)

akford351:
I like the how too. I"ve been thinking of that mod myself. Cause my filter is crap for one, and my filter box is broke.
Talking to performance truck owners and such though, they dont use stock air systems. Trucks need air, and letting it get air easly, and the ammount it needs is good. I think the stock ford system works fine, but its still lacking compared twards better systems which dont have dead space in the filer boxes and such.

If you look at the picture on that how too sight, the air box has gathered all that dirt at the bottom of the box. Thats not the best in my opinion, It just flys around in there.

Pluss the PCV valve is in there too. If you have any oil come back, it goes right in there into your filter, cause the air is recycled back into your engine.
oil+filters isnt' the best thing from what i understand.
Oil actually destroyed my PCV valve filter, I should probably get in there and check that to make sure its still somewhat holding up.

 

i think when i get a couple of bucks i will try to do that modification to my air system like that web site says. i think to take care of the crankcase vent tube i will cut a hole in one of the large tubes running to the TB and insert it there i have had no luck with trying to filter the tube in any other way.

 

I have that same setup on my truck, except mine has a outerwrap over the filter. Bang for the buck, its a very good mod and you can feel a nice performance increase. On mine I plugged the hole on the filter that's for the oil breather tube and just left that in the stock location for the reasons you stated... didn't want any oil getting in the filter. You can also get a small K&N oil breather filter that'll fit right on the valve cover as well.

 

akford351, it looks like you replaced the two big tubes coming out of the air filter, where did you get those? also, where did you get the red wire covers? is there still a need for the intake tube that comes out of the box to the hood?

 

I used two 6" pieces of 3" exhaust pipe to connect the air hoses to the filter. I left the bottom portion of the box intact... I figure that the tube going to the hood will suck some cold air when you start moving.

I got the red wire loom from www.summitracing.com
Its called Taylor Convoluted Tubing and its available in a bunch of different colors.

 

Saurian, you could go with a inexpensive route by getting a drop in style k&n for your existing air box and then using thermal barrier tape on the outside of your airbox to further insulate it from engine heat. You still will get about the same acceleration results as the more expensive FIPK system. Check out the dyno testing on the different set ups at performanceunlimited.com/projectmpg/aircleaner.html

 

where can i buy the filter KNN-RF-1012 ? jegs doesnt' have it and summit racing is out of stock and im not waiting 2 weeks just for it to be shipped.