I had a local Midas shop install my Borla catback two days ago. I have this annoying rattle coming from the passenger side when I have the window down. It almost sounds like a rattle snake. I thought it was a leak, so I took it back to the muffler shop.

First we checked the h-pipe. No leak. Check all the other connections. No leak. Then we retorqued everything to 34 ft-lbs just in case.

I still had the rattling sound. I don't think it's a leak, but something rubbing somewhere.

I jacked it up this evening and there seemed to be plenty of clearance for the rear sway bar. At one point I tried putting padding there to see if it would help. But stilll there was a rattle.

I've searched here and my350z.com for solutions, but nothing really definitive.

Only thing I can think of now is to weld the h-pipe and check the clearance with the "M" crossmember.

Just wondering if there anyone has experienced anything else that could cause such a rattle in the Borla system? Thanks.

 

But I think it is a loose clamp since I didn't use a torque wrench. I hear it when I rev to about 3500 RPMs and then let off the gas. . .there something that sounds like a hissing cobra, then goes away at idle. . .but I can only hear it if the passenger's window is down and I'm near a wall or garages or something. If you find any info, let me know too! I know my clearances are all good, since I checked that 3 days after installing it. But I'll have to get a torque wrench to confirm correct clamp tension. Good luck!

-drew-

 

No rattles or hissing from my Borla TD. I don't know if I would have chose Midas to install my exhaust. Then again I installed mine myself.

BTW, what's with the thread title? You make it sound like Borla is known for rattles.

 

On my350Z.com there are a lot of threads talking about rattles, ticking, and buzzing on the Borla system (due to so many connections). It's described as a rattle snake or like someone hanging paper out the window and letting it flap in the wind. It happens sometimes when I accelerate and then let off the gas. Mine really sounds like the chattering that the aliens made from the movie "Signs". I guess I was just frustrated when I was writing the thread.

I wish I had a lift.

 

You have to remember that the Z Borla is a whole different system then what the G has. You are the first G owner I have heard that has had a rattle problem with you Borla.

 

I took a look under the car this morning. Looks like there are no clearance issues with the pipes and the "m" crossmember. The sound is definitely coming from the passenger side.

I snapped a picture of the H-pipe clamp. I would like to know if I have the two pipes close enough together. Should I try to get the muffler shop to pull these pipes together and reclamp it. Perhaps I should go ahead and weld it. Thanks.

 

I don't know. I have the sedan and it's a different set-up. I found this online though:
http://www.borla.com/media/installations/140057.pdf

Looks like the pipes should run parallel where the h-pipe is.

 

I climbed under the G again tonight to see if I could further diagnose the strange "rattle snake rattle" that is hiding in my exhaust. First, here is what I did:
1. Inspected all joints and clamps
2. Loosened clamps and repositioned so that they are right to the edge of the pipe, like in Figure 11 of the Borla install document.
3. Tightened clamps to 34 ft-lb.
4. Made sure Cat flange bolts were tightened to 34 ft-lb. (G-manual says 34-44 ft-lb)
5. Started car, revved up to 2500. . .when I let of the gas, sure enough. . .PTCKTCKTCKTCKTCKTCK!

So, I decided to test out what are the cases that cause this sound. Test drove in MM mode, 1st gear and made the following observations:
From 1500-3000 RPMs, (checked in 500RPM increments), after a rapid let off of the gas, the sound occurs. Anything above 3000, nothing. . .or nothing audible. But as the engine revs down through 3000 the sound slowly starts and then gets the loudest from 2500-2000, then tapers off again as it passes below 1500.

My thoughts on possible causes:
The paper gaskets on the cats are stacked, and if there is any point that doesn't seal well, the exitting exhaust gas may cause the sound, like wind blowing through window blinds. Even though the Borla manual says to re-use the gaskets, I may just trash them since the G-manual specifically states that any time there is exhaust disassembly, the gaskets need to be replaced. Second, I did notice that my H-pipes had some flashing around the weld at the cross-member piece. I was going to buy a file and try to file them down a bit and smooth it out, but forgot to do it before I installed the kit. When I replace the gaskets I will file the flashing off the edges of the cross piece of the H-pipe, too.

Anyway, just my thoughts. If you come across anything else sooner, please let me know! I don't think that the sound is going to kill the car, but it is a little annoying.

L8r!

-drew-

 

Drewer, I really do think we have the same problem. I had my girlfriend in the car today and we rolled down the windows. We could really hear it when I let off the gas at around 2500 RPM. The sound definitely comes from the passenger side and she described the sound like driving over foil or something.

The connections to the cat are the only ones that I did not retorque down. So I'll need to do that.

I just can't enjoy the real sound of the Borla with this rattle.

 

I'm really starting to suspect the cat gaskets. . .especially since I didn't make sure that mine were "clean" when I re-attached the cat pipes. Oddly enough, I do also only hear it on the passenger's side. So maybe it's just the gasket on that side. . .
Anyway, I'll let ya know if I find anything new.

-drew

 

I have the RT Cats and the Borla exhaust. I hear a slight "hissing" noise when I let off the gas and the rpm's drop to idle.

Is this the sound you are hearing?

*click on link*
http://members.dslextreme.com/users/g35driver/noise.wmv

Drewer, thanks for pointing out that pdf file for the Borla Exhaust. I bought mine used so I always wanted a set of instructions to go with it.

 

Yeah. . .it kinda sounds like that. But for me it seems to last a little longer. . .no just like a quick "SHHHHHHHHHt!" It was kind of hard to tell, but the sound I hear REALLY sounds like a snake's rattle. . .or really fast marracas. <sp> Anyway, I'm going to check the cat gasket and go from there. . .

-drew-

 

It really does sound like fast marracas or something like ball bearings in the muffer. I've been under my car every morning/evening for the past three days. I tightened the bolts to the cats this morning, but it didn't help. Mine almost sounds like it's coming from the rear passenger side. You can really hear it going over bridges or through an over pass since the sound reflects back. Now I'm wondering if I just have a bad cat or something.

 

I have a similar problem but mine is a crack down the pre muffler. Having Borla send me a new one

 

Sure, give Drewer all the credit.