Stock airbox modification...

[fastdrvr23]

I decided to mess around a little this weekend with the factory airbox in my P5. I took the intake silencer off first and drove around a while, and could notice some improved throttle response around 4,000 to 4,750 Rpms, and a deeper intake sound. Well, this got me to wondering if the amount of airflow in general was being restricted alot with that shroud, since I felt a gain in performance... I finally decided to put the airbox back on, and actually modify the bottom/side of the box to let a higher volume of air in, especially on the bottom and fenderwell side of the box where the air would be cooler. Anyways, I drilled a few holes in the side and bottom of the box, and reassembled it with the intake shroud back on. I still noticed the increase of performance, and the throatier sound. I did this on my 1990 Protege 1.8, and had similar results for about 80,000 miles of driving.
Here's a pic of the side:

and the bottom:

with everything reinstalled:

another reinstalled:

Oh yeah, I am looking for another airbox to mess with also, so if you have an aftermarket intake, go look in the forsale forum, I am looking to buy another factory airbox.

If you have any questions about what I did, ask away.
Thanks,
Will

 

[P-Funk!]

I still have the stock/box and i do not see a 'silencer'...

What is it so i can delete it?

Thanks!

 

[fastdrvr23]

The "silencer" is the flat piece on top of the radiator that leads down and into the airbox. Supposedly it is there to bring in cooler air from outside the engine bay, and to keep the intake noise at a minimum. It made a big difference in sound without it there. I was more concerned about getting more air and as well as cooler air if possible, while remaining as close to stock as possible. That's why I modified the box itself, instead of leaving the resonator or "silencer" off.

 

[Liv2ride21]

What would the negative effects be of removing the silencer (both pieces) and keeping them off permanantly?

I switched to a K&N filter, and am trying to use it to it's potential... a friend just pulled off the plastic pieces that make up the silencer and said that all it is for is to keep it quiet. I'm sure it also gets a little bit colder air to come in, but am wondering if it is worth it at all to have it on.

any takers??

 

[fastdrvr23]

What would the negative effects be of removing the silencer (both pieces) and keeping them off permanantly?

I switched to a K&N filter, and am trying to use it to it's potential... a friend just pulled off the plastic pieces that make up the silencer and said that all it is for is to keep it quiet. I'm sure it also gets a little bit colder air to come in, but am wondering if it is worth it at all to have it on.

any takers??

I drove around with both peices of the silencer off for about an hour or so with my K&N. The main thing I noticed was an increase in intake noise... It felt like it gained a little in the higher 4K rpm range, but not too much. With the holes in the air box, I still feel those gains, with just a little less intake noise. It still sounds throaty, just not as loud. I figured the silencer can draw some cooler air (cooler than the engine compartment anyway) so I left it and let the box itself take more air in. I am pleased with the results so far. I drove it in a huge downpour of rain 3 days ago, and was forced to drive through a puddle about 8 inches deep. I checked it at home, the box and filter were completely dry. Even the box itself is cooler to the touch after normal driving for ~30 minutes. Anyways, good luck...

 

[o.g.sk8er]

i too, am driving without both pieces, have a k&n drop filter, home depot intake, using a 3 inch dryer exhaust hose coming from the stock airbox following down through that big hole on the drivers side and exiting below the front bumper. also, have the mazdaspeed factory muffler and i must say i'm quite impressed with my results. i would advise anyone to do this if you can't quite afford a cai. this combo is quiet up front, no growl like the cai. out the back is not that loud at all, but noticeable. i like it! as far as damage, the is little chance of anything bad happening. i have had mine in place for about a month now and the only thing i noticed was a slight drop in engine temp. maybe it's me, but i seems cooler now.

 

[Angel]

i,m also running with both silencer and the air box out . put a hks filter with a obx-r muffler. i love the way it sounds i'm like a sleeper on the streets. at the lights it looks like it cann't do much but surpise roars like a lion of the line. got to love our mazda(silverp5)

 

[yllwp5drvr]

I decided to mess around a little this weekend with the factory airbox in my P5. I took the intake silencer off first and drove around a while, and could notice some improved throttle response around 4,000 to 4,750 Rpms, and a deeper intake sound. Well, this got me to wondering if the amount of airflow in general was being restricted alot with that shroud, since I felt a gain in performance... I finally decided to put the airbox back on, and actually modify the bottom/side of the box to let a higher volume of air in, especially on the bottom and fenderwell side of the box where the air would be cooler. Anyways, I drilled a few holes in the side and bottom of the box, and reassembled it with the intake shroud back on. I still noticed the increase of performance, and the throatier sound. I did this on my 1990 Protege 1.8, and had similar results for about 80,000 miles of driving.
Here's a pic of the side:

and the bottom:

with everything reinstalled:

another reinstalled:

Oh yeah, I am looking for another airbox to mess with also, so if you have an aftermarket intake, go look in the forsale forum, I am looking to buy another factory airbox.

If you have any questions about what I did, ask away.
Thanks,
Will

you no what is better than that is going out and spending 20 to 30 dollars on a cone shaped racing filter from pep boys ro something like that will give u more h/p and better throttle response

 

[pr5owner]

just get this you know you want it !

GIVE into your temptations!!!!!! LOL actaully if you can find some way securing the filter and ripping out everything after the filter im sure you will get more power (slightly more not ALOT more).

 

[fastdrvr23]

Re: Re: Stock airbox modification...

you no what is better than that is going out and spending 20 to 30 dollars on a cone shaped racing filter from pep boys ro something like that will give u more h/p and better throttle response

I actually tried the monster conical K&N off my other car, pictured here:

The gains weren't any better than the K&N panel inside the drilled stock box. Since the stock airbox is now drawing air from the bottom, side, and outside, it should be cooler than the Conical filter by a good margin anyway. With the conical filter it made more noise, but other than that, it didn't feel any different at all. The main reason I did the holes in the airbox was to increase flow, without making as drastic a change as the Injen. (Those are quite nice by the way.) If I want power, I can always revert to my newly acquired T-type pictured above. I've been real happy with the change on the P5 though, it was well worth the 10 minutes of effort!