Has anyone dropped a K&N in the stock "airbox" then removed the forward portion of the intake "maze" from the grille area back to the filter housing? I'm wondering if that might function somewhat like the aftermarket short ram versions that don't drop into the fender well.

 

I dropped in a K&N filter, but never thought about removing the rest of the stock intake up to the filter box. That's interesting, but I don't know what the consequences would be.

Personally, I don't think you'd be drawing in enough air through the small hole that would be left in the engine bay. At least with the stock intake, the opening for the air is at the front of the hood and the air is sorta "rammed" into the intake. I don't think you'd get this effect if you removed the stock intake up to the filter box.

I say, try it out and let us know how it goes.

 

The stock intake IMO is very restrictive. I don't even think air gets rammed in, since the opening of the silencer sits atop the grille, and gets air most likely from the front of the engine bay.

By removing the silencer you are lessening the turbulance on the air caused by the silencer on the way to the airbox which is somewhat better. But removing it will leave a 2.75inch hole which faces up to get air, which IMO is too close to the engine and the limited clearance of the hood. Since hot air rises, and the opening faces up, alot of hot air is going into the engine, which may or may not decrease performance. That is why most aftermarket intakes have their openings facing downwards to take advantage of the cold air below. e.g. AEM Manual, Injen etc.

 

The main restriction in our air boxes seems to be that the MAF is mounted right at the top of the lid. The lid tapers downwards right before the MAF and the air coming up through the filter has to make a right angle turn into a tight area due to all the angles of the lid before it can enter the MAF. The K&N filter would work well if we could somehow straighten the air flow into the MAF. Maybe if someone makes an airbox out of aluminum or plastic that addresses this. For now the CAI's out there are the best bet.

 

ive done it, works for me, i did this a while back, all you have to do is unbolt a couple things, sounds better, its not like you gain 40HP but its a small gain.

 

Thanks for all the feedback so far. It's nice to see intelligent responses, not flaming wise-guys. I'm not about to hack anything up without polling other P5'ers.

 

You have any pics of what it looks like under the hood now?

 

I took all of the silencer junk out in front of the airbox. Even that 90 degree elbow that makes the hole face up is removable, but you actually have to take the airbox off to be able to remove the elbow, which is also connected to another silencer.

I ran it for a while with the elbow and last silencer in place and found a bit of an increase in power (very slight). It made more intake noise than stock under load, but you could hardly tell when just cruising around. (BTW, no K&N filter, just stock).

When I removed the elbow and silencer I noticed a significant increase in intake noise, even when on the expressway. It's amazing what that little elbow and silencer did for cutting intake noise!!! I think it sounds pretty good actually.

The airbox was looser after removing the elbow and silencer because these two pieces braced it somewhat. I got creative and drilled two holes on the bottom of the airbox and ran a zip tie to the bracket right under the airbox to brace it a bit more. (the holes were upstream of the filter of course).

I bet this little mod, along with a K&N would be pretty close to achieving most of the gains that a CAI or shorty would get you.

The only drawbacks I can think of is maybe more wet air would get into the airbox, since all the turns and twists it had before probably did a good job of getting most of the mist out the air if it were raining hard outside. I just check on my paper filter every once in a while to make sure its not falling apart. So far so good.

 

Hey, I've tried doing a lot of things to the stock airbox including drilling holes in the lower section to increase airflow. i've dynoed it twice now, and it makes no difference. As soon as you lift the lid and allow outside air to make a straight shot into the MAF, you gain 3-5 HP all over the RPM range. Don't run your car like that though. We only did this on the dyno to prove a point.

I just ordered a cone filter with a MAF adapter to go right on the end of the MAF. All you have to do is brace it in place with a brace similar to the ones they use on the CAI's. The adapter attaches to the MAF, and the filter slides right on the adapter. I'll see what that's good for. They are inexpensive so I figured I'd try that first since that's what the dyno place said to try. Only cost me $25 on Ebay.

 

I removed that plastic jungle including the airbox and put an APC 3 inch universal cone filter on. A K& N would have been better but it was an order and I couldn't wait.

It acts the same as a short ram intake. My guess is a 3-5 hp gain and sounds way better. Best of all I can change it back anytime I want in about 30 min.

Oh yeh, you have to put a hole in the end face plate of the cone filter to relocated a sensor from the airbox, not a big deal.

An inexpensive, easy and well worth the effort mod.

 

Last weekend I removed all the snorkels and stuff. I left the elbow that faces upwards because if you take the elbow off, the opening is facing the fan. Which means that water can get blown right into your filter/airbox (NOT GOOD). So for now I left the elbow on and since we have been getting drenched here in Maine, I noticed no water getting inside my airbox. I've got a Mazda Sport Exhaust in the mail right now, and I'm hoping the breathing gets better when I put that on. We'll see...

 

I guess everyone's tried doing **** with the airbox. I ran a dryer hose after I removed all the snorkels and elbows down to were the opening is for the plastic splash guard under the car. I found it really worked well, great sound too. Not too obnoxious. It worked better than just taking all the plastic stuff off and was quiter. I think it helped cut down on the turbulence entering the airbox since it had to travel through the hose first. Only problems were that it was rubbing against a hose/pipe by the rad and that in the winter, I was getting salt in my airbox...so I took it all out, but the whole airbox contraption back together. It was all pretty loose too.

I'm thinking I'm going to take it all off again. I have a K&N inside. I'm going to block off the hole in the front and cut out a new one on the bottom and run a pipe to a safe locations were it won't suck up water and will be away from engine heat. The air will be entering the box this way from the bottom and will be travelling in the same direction as the filter (more or less) is orientated thus hopefully cutting down on the turbulence. I really don't like the really loud sound of the cone intakes that much and I know what the box sound like with no intake mufflers....it's quite bareable. Anyways, I'll let you all know how it works when I get around to doing it.

 

I dropped in the K&N replacement and removed the front portion of the airbox maze so that all that was left was the upward bend in the front of the filter housing. Also pulled the battery cable for a bit. There was a notable difference in the off-idle throttle response along with a very small increase in intake noise. I don't think there was any appreciable increase in H.P. but the improved throttle response was well worth it. The result reminds me of raising the carburetor needles in my 80's -90's motorcycles to rid them of the dreaded EPA low-end lean surge. Cool.

 

I left the elbow but ran a 3" duct to the front lower grill.

Made a hell of a difference on the highway

Not afraid of water because the elbow piece is to catch water but have to make a deflector or something to stop the cooling fans blowing on the filter box, the removed piece block some of the hot air.

 

I had both pieces of my stock intake (before the air filter assembly) removed before I installed my Injen. Definitely sounded nicer, but I didn't really notice any gains (that I could tell). Not a bad idea I guess. I was worried about water getting into the little hole, but none ever did.