This problem has been getting me for sometime. I have searched on the forums, and reinspected my work only to avoid posting this problem but my options are getting slim. I am running a stock exhaust with a Berk test pipe. Upon my installation I noticed the test pipe was a good inch shorter than the actual cat it replaced. I proceeded with my installation anyway, (the exhaust does have some slack in it due the the hangers). The spring bolts in the front are tightened to Honda specs of 17lbs or something very close to that. The three rear bolts are very short that are provided with the pipe, the washers that are provided further enhance this problem due to there thickness. I tightened the rear bolts as best I could. Now on to my rattle problem. The first week of driving the the pipe made some noise, almost like a "rushing noise", for lack of better words under full throttle. I figured this was because the pipe is made of aluminum and the cat acts as kind of a muffler. Weeks later the cat has a faint rattle rattle that occurs only when Vtec is engaged now. I have reinspected my work and everything seems snug, 02 sensor, spring bolts, and the three bolts that connect to the exhaust. I am out of ideas for what could be causing this? I am really considering removing the pipe all together and replacing the oem cat. Has anybody else had problems with this or could maybe help out my situation. Thanks!

 

I don't know if this is going to solve your problem, but here is my advice. (and to preface this, I have the stock exhaust, stock header, and the berk test pipe as well).

When I did my install on the test pipe, I went to home depot and purchased longer bolts for the rear as I heard issues about the ones provided with the berk test pipe.

I purchased bolts that were about 1/4" longer to 1/2" longer (a couple of sizes just to have some choice when I was under the car bolting the test pipe in place).

-So, I'd suggest buying some longer bolts for the rear to see if you can get it set up a little more secure/easier.

I reused the gasket that connects the header to the test pipe, but a lot of people replace this as you can have an improper seal reusing the gasket.

-I'd suggest buying a new gasket from your Honda dealer and trying this new one while you're also in there replacing the bolts on the rear.

 

By any chance would you know the dimensions of the bolts you used? To be honest with you the exhuast doughnout looked perfectly fine, the thing that gets me is one of the spring bolts seems to be able to compress more than the other one. I dont want this test pipe to turn into rocket science 101 or anything...lol. This rattle is just killing me, I appreciate your comments.

BTW: is there a certain procedure to installing a test pipe. I bolted the three rear bolts first, then moved on the the spring bolts in the front. Is it possible the tightning of the rear bolts somehow threw off the alignment of those spring bolts that meet with the header?

 

I posted the sizes in the original group buy thread (which I think is gone now). They were identical to the bolts provided only 1/8" to 1/2" longer. All I did was take one of the bolts and nuts provided, and then matched it up to ones I found in the bins at home depot. I think it cost me $1.50 to buy 6 new bolts to try.

When I bolted up the test pipe I'm pretty sure I did both ends of the pipe at the same time... basically got one or two bolts in place at the rear and then did the ones at the front, then finished up the rear.

 

when you checked to see if the o2 sensor was tight, did you use your hand or a wrench? i had a rattle with my megan pipe and "checked" the o2 sensor by hand. if felt tight. rattle was still there. got back under and did a once-over on all the bolts and the o2 sensor with wrenches.....o2 sensor tightened up a bit more and that fixed my rattle! be careful not to overtighten the o2 sensor though. you don't want to break it.

 

I agree with before posts, check your gasket, maybe its fine, just not sealed correctly. I had a friend that went to a test pipe, and between 3k and 5k RPM, there was a distinct rattle. He got a new gasket (looked thicker than stock) and it went away completely. Also, since you had to pull back your stock exhaust .5 inch, check your hangers to make sure they are not causing anything metal to rub and rattle. Thats the only things I can think of. Good luck!

 

are you sure you're not confusing the sound that the car changes to with the test pipe installed with a "rattle" that isn't there? Particularly because you can ONLY hear it during vtec? to me, it sounds like it's just the exhaust sound change that was made. your exhaust, if it were to "rattle" would be most noticeable and actually rattle more in the lower rpm range, as more vibration is there in the exhaust system vs when you are in vtec.

 

It's thin wall stainless steel and not aluminum. Yes, It allows more sound out.