: G-Northstar Intake Plug



jadcock
04-07-07, 05:18 PM
I found a nice little plug for the intake tube that allows the removal of the intake silencer or resonator or whatever it's called. No performance characteristics are expected to change, I just wanted to clean up the engine bay and make transmission fluid and air filter inspections much easier. I guess all the G-platform Northstar cars have this setup? (98+ Seville and 00+ DeVille)

It's a rubber "quick connect" product designed for connecting lengths of PVC piping (rather than using PVC unions or elbows). But they also had plugs, or caps. The Quick Cap for 2" PVC pipe fit VERY snugly in the intake tube hole...almost like it was designed for it. Tightly enough for it to never fall out, but it's not so crammed in there so as to cause a deformation in the cap or intake tube and create an air leak. It's really a perfect size.

Found it at Home Depot. It was a buck and a half or something.

http://www.jnjhome.net/forumPics/cadillac/intake_plug_fp.jpg

danbuc
04-07-07, 05:29 PM
That's exactly what I used....bought if from Home Depot. Except I flipped it the other way around, so that the bottom was almost flush with the inside of the tube. That way, you don't have air rushing pass a large opening, since it's sits almost flush inside. Just a thought. Also, you might want to use some glue as well. I tried just using a metal band clamp, and one night on my way to pick some food up at the Outback, the plug came loose and logged itself flat up against the maf screen bogging the engine down until it stalled. Kinda threw me for a loop at first since I had no idea what happened, then I looked at the intake tube and saw the hole. At that point, I got some high strength RTV and lined the outside of the plug before I set it back in place. Hasn't moved since.

clarkz71
04-07-07, 05:30 PM
Nice.

Ekindler0584
04-07-07, 05:53 PM
I made mine originally out of two circles of pvc cut at different sizes. It felt real secure... But one night as I was getting on the freeway, manually shifting, and really getting on the gas... And it popped out!

Needless to say, the engine started bogging down, and I had to pull over to find the cap and put it back on. Since then, I have added an extra piece of pvc, so that it is three layered circles, with the middle one a quater inch thick and a quarter inch smaller than the two outside pieces... With a thin strap around it all to keep it from popping out...

So make sure yours is secured! (That is, if you always drive your caddy like you stole it!)

jadcock
04-07-07, 06:03 PM
Thanks guys for the comments.

Good comments about it becoming unsecured. That's actually why I installed it how I did...the "top" of the plug has much more deformity resistance than the "bottom" (hollow) end...simply because the top is where the flat of the cap is. I think the only way it could fall out is if it popped OUT, rather than getting sucked IN. But some rubber glue/RTV couldn't hurt. And if I do that, I might as well flip it to create the smoothest surface possible, as you suggested, Danbuc.

Edit: and I really don't want this getting sucked in. On the 2000+ engine, this is BEHIND the MAF, so if it did get sucked in, it'd lodge itself against the throttle butterfly, possibly blocking it open (dangerous). After thinking about this for about .3 seconds, I WILL go ahead and use some CA.

codewize
04-08-07, 11:26 PM
I'm scratching my head. What the heck are we talking about here. First of all what is a G platform Northstar? Secondly my car doesn't have ANYTHING that looks like that. My trans dipstick is wide open. No problem accessing it at all and my air filter box is totally exposed. No problems whipping off the couple of wing-nuts for inspection. Of course I did have the Volant box on there which made even more room but I'm talking about with the factory air box.

Is that a Seville? because my overflow tank isn't even on that side of the car.

jadcock
04-09-07, 09:33 AM
So the engine compartment on your '01 DTS looks totally different from that? I thought all G-platform Northstar cars (meaning 98-04 Seville and 00-05 DeVille) looked like that under the hood.

The Seville (beginning in '98) has a large resonator/silencer box that "plugged in" to the intake tube where my plug is. It as a loose slip-fit at best, and I didn't like the potential for dirty air getting in there anyway. And I did CA the plug to the tube, so it has an AIR TIGHT seal now (and won't come out).

If you could provide a pic of the underhood of your '01 DeVille, I'd love to see it. That would be my mistake if it's completely different. You learn something everyday, even if you think you already knew it. :)

Edit:

G-platform is the structure which began with the '95 Aurora and Riviera and which underpins the 98-04 Seville and 00-05 DeVille. This is a short article about it: http://en.wikipedia.org/wiki/GM_G_platform_%28FWD%29

This following Wikipedia article claims that the recent FWD Cadillac models were still technically K-platform cars, though does admit that it's based on the G-platform: http://en.wikipedia.org/wiki/GM_K_platform_%28FWD%29

The 1998 Seville is generally referred to as being on the G-platform, with the DeVille joining it in 2000. If that Wikipedia article is correct, and I guess that it probably is, the Cadillac platforms are still officially called "K"...although they share all the signature trademarks of the G-platform, like the battery under the rear seat. The 98-04 Seville also has the coolant surge tank in front of the driver side strut, just like in the Aurora. Since the Seville shared that design, I figured the DeVille would also, but I must be incorrect. Prior to 1998, the Seville's pressure surge tank was in front of the passenger side strut -- is that where it is on your '01 DeVille?

codewize
04-09-07, 03:49 PM
Nope, my layout is totally different. I would love to provide pics but I think I deleted the ones I had so we'll have to wait until tomorrow when I get the car back from the tranny guy.

OffThaHorseCEO
04-09-07, 04:33 PM
here it is

Submariner409
04-09-07, 07:00 PM
Late 2002 (02-02) STS, Magneride, strut bar, CORSA, some tricks. Resonator in question is kidney-shaped box over driver's side transmission area. PITA for air filter changes/cleanups. Thanks for the butt plug tip...........Jim

dwight.j.carter
04-09-07, 07:22 PM
Guys I hate to tell you this but that little add on plastic box is to help in cooling the air before it gets to the motor. I won't be taking mine off anytime soon. I would like to find a cold air intake for mine though made of rubber or plastic as the metal ones on ebay get to hot and don't work right.

Submariner409
04-09-07, 07:26 PM
Dwight......Think about what you just said about a sealed resonator box cooling air. Maybe theoretically, by damping intake pulses, but the route to the intake valve is already damped by the MAF, throttlebody butterfly, and the standing wave pulses in the tuned intake runners.

codewize
04-09-07, 07:45 PM
Yup, that's it al right. Thanks

here it is

danbuc
04-09-07, 07:55 PM
Guys I hate to tell you this but that little add on plastic box is to help in cooling the air before it gets to the motor. I won't be taking mine off anytime soon. I would like to find a cold air intake for mine though made of rubber or plastic as the metal ones on ebay get to hot and don't work right.


Haha..WRONG!

It's a resonance chamber tuned to reduce induction noise in the intake system under heavy load.


You are correct that a cai made out of metal that's placed in the engine bay is counter-productive. The best material to use would likely be white pvc piping. It's a light colored plastic, and therefor will not transfer heat very well...which is perfect.

danbuc
04-10-07, 12:54 AM
dwight.j.carter, I didn't mean to sounds like a complete douchebag in my response by the way. Long day, got written up at work, and have a generally sh**ty ass week. Sorry to come at you like that....just in case you happen to read it the wrong way.

jadcock
04-10-07, 08:01 AM
At the speed at which the air flows through the intake duct, most of the "airflow" is bypassing that resonator anyway. Sound waves probably don't, but the airflow will. Besides, I'm not sure how a reservoir in a hot engine bay would help cool the air. If anything, it's just a chamber with a bunch of HOT air sitting in it. The time it takes for the air to travel from the outside, through the intake snorkel, through the filter, through the MAF, and into the throttle butterfly, at normal engine speeds, could probably be measured in seconds, if not less; there's nothing you can do short of applying ice to the intake system (which racers do between runs) to cool that air down lower than what it already is at the point of entry at the snorkel and filter.

Edit: For what it's worth, I drove the car for the first time today after doing the "butt plug" and, as expected, noticed no change in engine noise.

Submariner409
04-10-07, 05:06 PM
:highfive: DITTO !!! Did a 100 mile country road run this afternoon after the butt plug install (cut a couple of shallow curves in the plug skirt to equal the curves in the OEM connector hose and used the supplied hose clamp judiciously....). Same $2.65 plug as earlier posts......No change in noise or anything else I could hear/feel. Makes the transmission side MUCH cleaner and easier to get to...........

Ranger
04-11-07, 12:50 AM
That thing is a silencer and has nothing to do with cooling. If you follow the intake, you'll see that is already drawing cool air from behind the headlight assembly.

jadcock
04-11-07, 08:47 AM
By the way, I found how to get the noise back that I loved from my '97. (No, not permanently.)

The Seville has a computer access cover just behind the left headlight area. If you open this up, you can see the computer and the front (dirty) side of the filter. Removing this cover effectively opens up the front of the airbox to ambient (underhood) air. It has absolutely no effect on actual filtration, since it opens up the dirty side only.

The sound at WOT is exhilarating. The engine sounds so exotic. It's totally habit-forming.

You can see my choir robe on, so save the preaching. ;) I know it pulls hot underhood air, I'm not going to keep the lid off, I just wanted to try it to see how it sounded. But dang...it sounds good. :)

And another by the way, when I did that yesterday, I felt just how HOT and PLIABLE the rubber intake duct and butt plug got after the engine compartment was fully warmed up. I'm glad I CA-ed the plug to the tube. I may even add a nice bead of RTV around the seam just to really "cap" it off. It got REAL pliable, and it would have been a LOT easier to remove (fall out) when hot vs. when cold. I never actually thought about using that hose clamp that came with it, but might think about that as anOTHER added measure. ;)

ewill3rd
04-11-07, 08:59 AM
That chamber controls noise and airflow, it is only on Seville.
Devilles have a different design airbox.
At least as far as my fading memory can recall.

"If it ain't broke, don't fix it".
As mentioned if you put this in behind the MAF and it gets sucked in... well you can do the math.
It probably won't do any real damage but it will open up a can of worms while you try to extract it from the intake.

Personally I hate those freakin' things. Makes checking and changing the filter a real pain in the rump, but I still put them back on if they come off.

jadcock
04-11-07, 10:13 AM
As mentioned if you put this in behind the MAF and it gets sucked in... well you can do the math.
It probably won't do any real damage but it will open up a can of worms while you try to extract it from the intake.


Exactly. What I'd like to find is some RTV-like stuff that will vulcanize rubber...essentially BOND the plug to the tube. Still, with the CA and the clamp, there's really no way it's coming out (or in).

JimD
04-11-07, 10:39 AM
Exactly. What I'd like to find is some RTV-like stuff that will vulcanize rubber...essentially BOND the plug to the tube. Still, with the CA and the clamp, there's really no way it's coming out (or in).Trust 3M when it comes to making two things stick together. Any GM parts counter should have 3M Super Weatherstrip Adhesive Black, 3M part # 051135 08008. If the parts counter can't help you, talk to the body shop manager.

cadillac8686
10-03-07, 12:10 PM
I have an 02: STS and I am looking for anything to improve performance. What kind of actual gains could I see with this?

JimD
10-03-07, 02:37 PM
No impact on performance but it sure is a lot easier to check the transmission fluid level or change the air filter.

AJxtcman
10-03-07, 02:43 PM
Guys I hate to tell you this but that little add on plastic box is to help in cooling the air before it gets to the motor. I won't be taking mine off anytime soon. I would like to find a cold air intake for mine though made of rubber or plastic as the metal ones on ebay get to hot and don't work right.


That thing is a silencer and has nothing to do with cooling. If you follow the intake, you'll see that is already drawing cool air from behind the headlight assembly.

I was told that it is a FART BOX aka expansion chamber for backfires. I was told that it was in place to protect the MAF. I will look for the training materials.

I will find some information on the air boxes and noise silencing for different areas.

RPO--R1X--Noise Control Air Cleaner, ECM, EXH Inter Pipe
They also have different PCM calibrations for Noise Control:yup:

Ranger
10-03-07, 06:18 PM
Isn't the pressure relief valve on the front of the manifold for backfires? Besides, any pressure from a backfire would have to pass through the MAF BEFORE it got to the silencer or whatever it is called.

AJxtcman
10-03-07, 06:39 PM
Yes that is what the valve is for. I am just telling you what that told me at shcool.
The MAF is on the other side on 00+
http://www.jnjhome.net/forumPics/cadillac/intake_plug_fp.jpg

Ranger
10-03-07, 08:13 PM
Ah, so it is. I keep picturing my '97. I should know better.