: air filter

04-10-08, 10:36 PM
im wonder ing what happens if i replace the stock filter for a 99 sts to a k&n cone filter? does it do anything or just deepens the engine sound?

04-10-08, 10:45 PM
It costs you some $$$, requires some periodic maintenance, does nothing better or worse for cleaning the incoming air, and, depending on how much you're willing to hack out of the air box, changes the sound (only) of the engine intake at WOT.

BUT, go back in the Northstar Performance threads a year or more and find the air filter/air intake/CAI threads. You can do the same noise modification with what you now have, costing a lot less $$$, and using a bit of ingenuity.

No, it won't look as cutesy at the drive-in, but you will have accomplished a real beneficial modification as opposed to buying fluff.

(Just found your other post on the same subject up in Seville. Why the double post ???)

04-10-08, 10:55 PM
Im planning to take off the whole box and replace it with a stainless steel pipe im just wondering what the heck is the little oval-like piece above the filter box? because as the rubber tube goes to the box, there is also an opening that the oval-like piece is connected to it also.
Also i just used the ebay method :D bought the whole thing for about $50
Also with the stock removal as i looked into it, It is such an annoyance. They placed a screw at the bottom under the box... lucky i am able to fit my hand in there

04-10-08, 11:06 PM
Now what do you do with the PCM ?? It's under the black plastic cover with an air filter change date on it........ Go back to my post ^^ and add "butt plug" to your search efforts........

If you went to eBay already, and have the aftermarket setup on the way, why post in the first place ??

Click on the pic and scroll in. What you cannot see is the entire side of the air intake box closest to you is opened into the left fenderwell and sealed with 2 x 2 foam gasketing.

04-10-08, 11:24 PM
because i need more info about this.
also where can i get the "butt plug"?
Lastly i noticed this section after the last post...sorry about that

04-12-08, 02:04 PM
Where is it possible to find the plug? Home depot or pepboy a possibility?

04-12-08, 03:37 PM
The "butt plug" is a non-performance enhancing removal of the kidney-shaped resonator which sits atop the intake tubing just after the MAF in later Sevilles. It cleans up the engine compartment visually and makes transmission fluid checking a breeze.

Go to Home Depot or Lowes, or even a local hardware store and pick up a 2" rubber pipe cap, used in PVC drain pipe work. It comes with a s/s hose clamp. $2.00. Remove the resonator (Torx screw and pull straight up) and convoluted hose from the TB and MAF, carefully (TB end first), pull and check the MAF but don't even consider modifications, and you might as well put in a new WIX panel while you're at it. Why WIX ? Because it has a LOT more filtering surface than other replacements. Use an old chrome Philips screw from your junk box to replace the Torx screw. Temporarily install the rubber plug, skirt down, until the top is flush with the hole left by the resonator, look into the intake hose and mark the intruding plug skirt with a Sharpie. Cut away the excess skirt until the installation looks fair. Pull the plug back out and reassemble the piping, making sure that the MAF is properly oriented to the locator tabs in the connector sleeve. The airflow straightener screen and airfoil are suposed to be oriented properly to insure clean flow to the TB area. Now install the plug with a smear of RTV gasket maker gel and use the supplied hose clamp to just barely compress the resonator mounting sleeve around the plug. Use my picture in Post #4 for info. The intake air noise will be a bit louder at WOT, but no difference in daily driving.

04-12-08, 04:33 PM

I still dont understand what the kidney-shaped resonator does
I understand everthing but
After the installation of the cone filter should i keep the plug on or replace it back to the resonator?

04-12-08, 07:33 PM
A resonator is a resonator. It quiets sound waves in a labyrinth or tube. (This is a Cadillac, remember ??) When you install your aftermarket cone filter kit what you have left will bear no resemblance to what's in there now. All of those carefully designed hoses and filter box as well as the resonator will be gone, your PCM will be hanging out somewhere, exposed to moisture and engine room heat, and your cone filter will be sucking hot engine room air also. You may well experience a low to midrange throttle stumble from incorrect airflow monitoring. But it might look cute to someone who doesn't know better.

Please, please go back in these performance threads as well as Seville/Deville and read up on air filters, so-called cold air intakes, CAI, anything you can find on intake work BEFORE you butcher your present OEM system.

Don't take only my word for what you're contemplating.......let some of our other members chime in. You're in here to learn BEFORE you chop things up. (You know why you got the aftermarket setup on eBay for $50 ?? Because someone else discovered it didn't work.)

04-13-08, 09:33 AM
at least on a deville (96-99) the only way to do this properly is the way i am going to do it.

remove windshield washer fluid tank
cut out steel
run tubing down into fenderwell/airdam
seal off said area

then you still need to:

relocate IAT sensor
fab new washer fluid tank
find a place for PCM and shield it from heat/actively cool it

it is not a plug & play deal...it is not something a 50 dollar ebay "kit" will get you. it's an all custom gig...and even then i wouldnt expect more than a 1-2 tenth improvement at the track (if any). Unless you engineer it properly, you will be opening yourself up to alot of problems with the PCM and/or crap getting sucked up into your motor...

i should have pics when i get around to fabbing mine up...steps one and two are already complete (removal of stock washer fluid tank and cutting the steel out)