If you still have a stock exhaust and you have a loud rattle coming from underneath the engine. There is a 95% chance it is your A-Pipe. This pipe is sometimes called the Y-pipe and it connects between the exhaust Manifold and Catalytic convertor. Metallic rattling occurs between 2800 - 3500 RPM's. The rattle is created when the exhaust gasses are moiving at a particular speed and pressure through the A-Pipe and the inner exhuast tube begins to resonate. Same thing happens when you play a flute, blow into a bottle, or when a subwoofer gets especially louder at just the right frequency when mounted in a tuned ported box, also similar to how church organ pianos work.

I discovered the inner tube was originally wraped with sound deadner and the outer tube was supposed to contain it. Years later the sound deadner begins to burn up and slowly disintegrate and exit through your tail pipe. The inner pipe never actually vibrates enough to hit the outer pipe or anything at all. That simply is what 16 guage irregularly shaped steel sounds like when it resonates.

So here is how you fix it.

Tools. 12mm, 14mm, ratchet, breaker bar(or impact gun), 8" extension, 12mm open end wrench.

1. Remove the A-pipe
a. Spray PB Blaster on all the nuts (highly recomended)
b. 12mm remove the 3 exhaust manifold flange nuts.
c. 12mm and 14mm remove the 2 spring bolts that connect the cat.
d. 12mm remove the 2 A-pipe mounting nuts.
e. Pull straight down from the exhaust flange then pull towards front of car.

2. Looking at the end of the A-pipe where it connects to the cat, you will be able to see the gap between the inner pipe and outer pipe. You should also notice trace amounts of sound deadening material sparsley scattered around the pipe. If you take a screw driver and tap the inside pipe you will hear a familiar ping.

3. Take your A-pipe to a local welder or exhaust shop and have him weld a small bead to fill that gap. Make sure you tell him NOT to distort the outer tube's round smooth diameter. You will need to remove the old doughnut gasket before he welds. I reused my doughnut gasket and it worked fine, otherwise Autozone will probably have to order you one. I also replaced the exhaust flange gaskets as well, (2 round metal o-rings).

4. For bonus points you can grind down the welds to make it smooth, but YOU DONT HAVE TO. It will look like a 6 gauge shiny steel tube that will NEVER create an audibale resonance ever again. Unless you can manage to get your 1.8 liter at about 13,000 rpms you might hear a low frequency tuba note, or not.

5. Reinstall is same as reverse.

I did this to my 94 gsr and figured it out. I think most other year GSR's have the same problems. I also have the original heat shields and never had a problem with those before. 170,000 miles and still no issues with those. I do believe Honda was supposed to have done this to the A-Pipe but for some odd reason it never made it back to an engineers revision notes. Or it was to costly.





Modified by Sweetsystem at 5:49 AM 10/29/2006

 

You are a very smart man, thanks for the info, the infamous integra rattle gets really annoying. bookmarked btw do you have pics just for reference?

 

will post pics soon.

 

Is this only for the stock GSR header?

I have a JDM ITR header on mine and the rattle is HORRIBLE. I thought it was my muffler, like a baffle blown in it or something.

 

I can only know for SURE the problem exists on the USDM 94 GSR. I would assume most other Exhaust Manifolds that were built in the same way would eventually have the same issue as well. Take it out and test it. Takes like 1 hour to remove (Start to finish). All you have to do is listen carefully and narrow down where the noise is coming from. I had a friend rev the car while I was underneath. I had leather gloves on while I squezed and pushed on the heatshields, connections, and pipes till I narrowed down the noise source. I have no experiance with a Muffler baffle coming loose, or the packing material inside it deteriorating. Good luck.

I do think they all have this problem though.


Modified by Sweetsystem at 8:14 PM 10/30/2006

 

well, if you can, post the pics. I loathe the way my GSR sounds from 2800-3300.. Blahh

** Edit** I don;t have a Y-Pipe or a Cat.. The header connects to the test pipe which in turn connects the rest of the exhaust...

I'm screwed.

 

I bet you the Type R Header is built the same way. Take it off and look at the joint where it meets the cat. You will see an inner pipe, shine a light between the inner and outer pipe and if you clearly see that the light travels about 2-3 inches deep then there is your problem. Perform said repair. If you can still see the packing material then thats not your problem. If and when you do figure out what the issue is Please Let me know or post to this thread or somthing.

 

i'm running

dc 4-2-1
w/ greddy evo1

and mine is around 2.1-2.4 i think... is this the same rattle or is my rattle something else because it is not withen your listed range of 2.8+

the only heatshield i have is on the cat i think

 

niceee now i know why my gsr rattles lols thanks dude!

 

dont think it helped me yet my rattle could possibly be the tranny but why would it be the tranny at 2.1-2.4

lol

heeelp

 

I also have the DC sport header and have the same rattle. I have not checked to see what is making the awful noise yet.

 

is it between 2.1-2.5~~?

 

, thanks man, I hate the way my gsr sounds at 3k, that rattle is so bad ahh, so annoying.

 

check your throwout bearing in your tranny just a suggestion

 

i know that my 93 da had the same problem. luckily, i just dropped $450 on a jdm 5zigen header (jasma certified ).

 

Holy thread digging batman!!!

I've had 2 different OEM Y-pipes on my car, and both of them had the rattle fixed by an exhaust shop simply making a hole in each pipe of the Y, then welding it back up. The weld secures the inner wall of the pipe.

However I think it was worked loose and started rattling again on my car a few years back.

 

Add to FAQ?

 

dooo it.

 

Does the DC Header have an inner pipe?

If so the rattle may be coming from your DC pipe, in which case the above directions would apply.

 

imma try taking off the cat heatshield soon and see if its that, i read another post few days ago and solved the problem for a good amount of people

 

good stuff

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Sweetsystem &raquo;</TD></TR><TR><TD CLASS="quote">Does the DC Header have an inner pipe?

If so the rattle may be coming from your DC pipe, in which case the above directions would apply.</TD></TR></TABLE>

I have not seen any aftermarket header that had double-walled pipes like OEM does.

 

I had an annoying metallic ringing when I had a dc sports 4-1 header, random tech hi-flow cat, and apexi wsII catback. IIRC it only happened at ~3-3.5k rpm. I swapped out the dc header for an edelbrock 4-2-1 and still had the same problem. I think mine was due to the heat shield welded to the random tech cat.

Oddly enough after getting a ticket for loud exhaust, I've since went back to oem ls exhaust and didn't have a problem (yet).

 

Well it doesnt sound like you have an exhaust problem then. Have you heard someone elses known exhaust problem before to compare too?

Does your rattle sound occur when just in park with gear shift in neutral? Throwout bearings can make this rattle sound too if they have loose bearings.

 

I cant get those spring bolts off for the life of me. I'm hoping that a breaker bar and some PB blaster will help or I'm screwed.