Thread: Get whine from stock GTP airbox

Hey, stock GP drivers! Heres a free one for your Saturday afternoon. Advanced GPers with CAI can go right past this post...

If you have a 98-03 3800 GP (whichever years had the "improved" airbox like a 99-up as shown) N/A or supercharged with the stock airbox, check this out:

This how-to shows how to let supercharger noise out of a stock airbox. A simple and free one hour modification, all you need is a drill and bit after removing the airbox. If you don't plan on major mods but would like to let the M90 speak, this is for you. It might howl on GTs also but I have not tried it on one. No claims one way or the other about power. I just wanted noise and the 99 GTP coupe already had a K&N drop-in. I didn't think the mod would be as successful as it was but after enjoying the nice level of whine for awhile, I figured some others may want to try this as a no buck alternative to messy cone filters. I tried that and it was a little too noisy for my taste.

First, remove the entire airbox



Now, see the phillips screw on this piece? Remove that baffle and leave it out.



This group of grooves on the outside of the box is at the baffled area



I used a 1/8" drill bit in a Dremel tool. Drill a series of holes along each groove then carve it out from there, carefully with the bit.



Heres the inside. You can feel free do it more neatly!



Slap it all back together and you can barely even find an angle to see them from. Still looks factory fresh.



Click on these images to compare before and after sound. Nice and whiny with windows up or down.

Before:



After:



Theres no reason this wouldn't add cool sound to a N/A car as well. TRY IT! Kinda looks to me like GM intended for us to do this if desired, by the way the box is made. There is another row of grooves across the top of the box that could also be cut out but this seems to be sufficient, and keeps the filter clean and dry like stock. Just a poor boy mod, really.

When I get some time I'll pull apart the air box on my 98 gt (has the old style box) and see what can be done to it as far as letting more air in

Originally Posted by 87IROCZOWNER69

When I get some time I'll pull apart the air box on my 98 gt (has the old style box) and see what can be done to it as far as letting more air in

Go for it, man. This was just to let the sound out, with no consideration given to airflow. But the slots are right at the filter and away from heat.

Originally Posted by Pest

Excellent write up. this looks nice and clean, I think you are right about a GM engineer thinking about the enthusiast and giving us a template. looks like there was a motorhead working that day I'm going to do this tonight. Registered just to say thanks.

You're welcome! Thats not very pest-y of you to say. Keep reading these forums, they are very informative. Careful with the drill, and with the right foot tomorrow.

I was going to do that today, but then I opened my airbox and didn't find the baffle in there. I guess my box is different. I have a 99. Anyway, I drilled holes in the side of the airbox. I like the sound, makes me feel like I have a supercharger... in my dreams. But yeah, it's giving me a whistle sound that I enjoy. Smaller holes=louder pitches, I'm probably going to do some more. Thanks for the idea. BTW, here's a pic of my airbox, the part that you had.

Originally Posted by chrisdaboss

yeah, it's giving me a whistle sound that I enjoy.

Thats odd, I thought all the 98-up 3800s had the same box but yours doesn't even have bosses for screw holes. Bonus time saver! You're welcome and enjoy. I wish I had thought of it when I was driving a non-supercharged one.

Hey thanks for the replies guys. Yep all you really need is a drill or Dremel-type tool. When its heavy traffic time, the whine isn't anything to be excited about. But when I drive for pleasure, I listen for it and it gives me even more. So-

I deem this: "The Whine Box Mod".

*bump thread for update. It kinda sounds like a turbo diesel at shifts. so cool.

Originally Posted by tc300

Anybody done this to a N/A GP??

you cant get whine from an n/a car

might as well just make an intake so you can hear the awesome roar

Originally Posted by tc300

Anybody done this to a N/A GP??

The member in post #6 of this thread ("chrisdaboss") did. Apparently it gives a whistle sound similar to an open element intake.

Originally Posted by tc300

Anybody done this to a N/A GP??

yeah, I have a 99 3800 N/A. I get some whistle at shifts sometimes, I drilled holes in mine. It's a cheap, fun mod.

What is a stock air box?

Original equipment air filter / computer housing, Slick. Made of plastic, as shown in previous photos. Thanks for playing Jeopardy.