Gmpp Cai Nbs

Raymond Lowe · September 7, 2009

(x-posted in Denalitrucks.com)

Some time ago, I removed my GM CAI. I didn't care for the noise and it didn't do anything for the bottom end. So the other day I decided to put it back on and give it a re-evaluation.

The noise in question is the bwwaaaaa sound like when we used to flip the air cleaner lid back in the 70's. In those days, it didn't do squat for the engine (other than suck in super hot air) but we thought it sounded impressive when you matted it.

The new CAI made a similiar sound when you got on the throttle a bit more aggressively. I was not impressed and I found it a little annoying after awhile.

So, while putting the CAI kit back on, I checked out the underside of the lid and then the top flange of the housing. Guess what? The two surfaces don't meet at all . There's a gap sucking in air since the top lid is a poor fit to the housing. My kit didn't come with a lid seal and a check on-line doesn't show any kind of a lid seal in the parts list - just the seal for the housing to fender port. So I'm guessing anybody else that has installed one of these CAI kits might also run into this situation. The lid really is a poor casting when it comes to fitting the air box.

I happen to have some good automotive quality "D" foam EPDM seal 3/8" tall by 1/2" wide lying around, although 5/16x3/8" wide would be even better if you can find some. It's peel n' stick so it was a simple 5 minute job adding a seal to the top of the box. The point of doing this was to keep the engine bay warm air from being drawn into the box.

But the big surprise was when I got on the road and got on the throttle. Gone was that annoying loud air cleaner hum. It still sounds mean when you really get on the gas! And it's now sucking just the cool air from the fender port likes it's supposed to.

oldschool327 · September 8, 2009

I did the same thing to my AEM brute force system. I used 3/4 D foam and lined the intake tube hole along with the hood enclosure. I marked it with red roofing snapline chalk and shut the hood to verify it made contact all the way around. Completely sealed the sytem. It was by far not sealed when AEM sent it to me and infact very poorly sealed. Now it is perfect and has the same noise characteristics as you speak of. I wis the Manufactures would pay better attention to these finer details.

MS3DALE · September 8, 2009

Hmm,My lid fits the housing fine.

LawmanSS · September 8, 2009

Hmm,My lid fits the housing fine.

Mine, too. Perhaps it's a manufacturing defect with your airbox?

Raymond Lowe · September 8, 2009

Hmm,My lid fits the housing fine.

Mine, too. Perhaps it's a manufacturing defect with your airbox?

A possibility, but not likely.

The screws line up perfectly and these are molded/cast parts. You might not know there's a problem by simply screwing the lid on. Sure it "fits" but it was far from air-tight. I just can't get over the change in noise that sealing up that little gap made.

Pilot12 · September 8, 2009

The noise in question is the bwwaaaaa sound like when we used to flip the air cleaner lid back in the 70's. In those days, it didn't do squat for the engine (other than suck in super hot air) but we thought it sounded impressive when you matted it.

I remember doing that to my dad's '71 F100 with the 360ci. Man, it sure sounded cool! Poor man's glass packs. He didn't let me leave it that way though. That truck was quick.....Still is. Next time I see it, think I'll sneak out and turn that cover over.

VMax2007 · September 8, 2009

Hmm,My lid fits the housing fine.

Mine, too. Perhaps it's a manufacturing defect with your airbox?

A possibility, but not likely.

The screws line up perfectly and these are molded/cast parts. You might not know there's a problem by simply screwing the lid on. Sure it "fits" but it was far from air-tight. I just can't get over the change in noise that sealing up that little gap made.

Thanks for the info! I will check mine out tonight.

Pilot12 · September 8, 2009

Some time ago, I removed my GM CAI. I didn't care for the noise and it didn't do anything for the bottom end. So the other day I decided to put it back on and give it a re-evaluation.

But the big surprise was when I got on the road and got on the throttle. Gone was that annoying loud air cleaner hum. It still sounds mean when you really get on the gas! And it's now sucking just the cool air from the fender port likes it's supposed to.

So it doesn't make so much noise, but does it improve your performance? You said it didn't do anything for your bottom end before, how 'bout now?

07SLT · September 8, 2009

(x-posted in Denalitrucks.com)

Some time ago, I removed my GM CAI. I didn't care for the noise and it didn't do anything for the bottom end. So the other day I decided to put it back on and give it a re-evaluation.

The noise in question is the bwwaaaaa sound like when we used to flip the air cleaner lid back in the 70's. In those days, it didn't do squat for the engine (other than suck in super hot air) but we thought it sounded impressive when you matted it.

The new CAI made a similiar sound when you got on the throttle a bit more aggressively. I was not impressed and I found it a little annoying after awhile.

So, while putting the CAI kit back on, I checked out the underside of the lid and then the top flange of the housing. Guess what? The two surfaces don't meet at all . There's a gap sucking in air since the top lid is a poor fit to the housing. My kit didn't come with a lid seal and a check on-line doesn't show any kind of a lid seal in the parts list - just the seal for the housing to fender port. So I'm guessing anybody else that has installed one of these CAI kits might also run into this situation. The lid really is a poor casting when it comes to fitting the air box.

I happen to have some good automotive quality "D" foam EPDM seal 3/8" tall by 1/2" wide lying around, although 5/16x3/8" wide would be even better if you can find some. It's peel n' stick so it was a simple 5 minute job adding a seal to the top of the box. The point of doing this was to keep the engine bay warm air from being drawn into the box.

But the big surprise was when I got on the road and got on the throttle. Gone was that annoying loud air cleaner hum. It still sounds mean when you really get on the gas! And it's now sucking just the cool air from the fender port likes it's supposed to.

I bought and shortly after sold my GM CAI for that same noise problem........it sounded cheap and unrefined (like flipping the lid on my old 72 chev but that noise was free!!).