Has anyone experienced a rattle eminating from the flex pipe upon cold startup that lasts, oh, about 15-20 minutes and is more pronounced at about 1800 or 1900 RPM? I just had it installed, my installer has checked everything and the sound is coming from those flexpipes, we have no doubt. Even when driving and the engine is warm..I can hear a hint of the rattle when getting on it and around 3500 rpms. We think there may be a bad weld, shred of metal, or something that may correct itself after some heat cycles. I've only driven about 200 miles since the install. Anybody with similar experiences please share. The sound is pretty much identical to that of a bad heat shield, but we know it isn't.

thanks,


Scott

 

I had the rattle also. My problem was between 1500 and 2500 rpms the exhaust would resonate causing the midpipe to vibrate against the brace on the bottom. I just cut the hanger off the midpipe and had someone reweld it about another 1/2 inch lower. Lowering the hanger on the midpipe will raise it when mounted.

 

Yes I have it as well. I also had a problem with the weld on the back side of the resonator. The weld completely cracked (360 degrees). I could literally separate the muffler side from the Y-pipe side. Luckily it didn't fall apart while driving. I had it welded and it's good a new but you may want to check the welds frequently.

 

No rattle on mine!

 

I posted earlier this year about my rattling issues and having a hanger fabricated which completely eliminated.

-Steve

 

STX and/or FAILSAFE: On visual inspection, was it apparent that there would be a vibration situation set up? I mean, when we inspected mine visually and by just simply grabbing stuff to see what shook, none of the places seemed loose, touching other parts, or otherwise. Just wondering if you initially had the same impression or if it was apparent because it was so obvious right from the get-go what your problem was?

 

We've had my car on the lift a few times and inspected the exhaust while the car is running. The exhaust firmly in place and is not rattling against anything.
It's coming from the flex pipes but I figured it was because my flex pipes were slightly frayed (from scraping speed bumps).

 

Same here, as I said in my initial post, we really believe it is coming from the flex pipes. Sounds like you still have the problem from the way you describe it; how long has your system been on? I'm hoping that with a little time (and I do mean a little) that it will resolve itself. If yours didn't do it at first but is now, and you know you've hit some bumps...makes me think my flex pipes may really be defective from the start...poor weld, metal fragments...i don't know what else. Thanks for your feedback...let me know if anything else comes to mind about your experience.

 

Initially I couldn't figure out where the sound was coming from. I couldn't see where it could be vibrating against anything and it had plenty of clearance over the crossmember. Then one day I after driving the car really hard and got out and looked at the exhaust with the car still very hot. What I noticed was the midpipe was sagging and almost hitting the crossmember. I had my friend give it gas while I was watching and I could see it vibrate and hit the crossmember. So to fix it I just cut the hanger off the midpipe and had someone reweld it in order to get the clearance. My exhaust doesn't have a rattle anymore but I due have a rasp in between the same RPM range. I think even the old Z's get the rasp with free flowing exhaust.

 

I had the vibration last year after install. The weather was just getting colder and cold starts would produce a vibration for a few minutes until the system warmed up. It went away after a few weeks and so far with the weather getting cold again it has not come back. When I researched the vibration last year I saw a few threads where people were adding a shim to one of the flanges.

 

tx. did you also hear some vibration at various points in the rev range? In other words, it is worse at approx. 1000, 1750-2000, then somewhere around 3300-3500. And I can have driven for more than an hour and I'll still here it just slightly enough for me to know it is there.

srm

 

Regardless of whether the exhaust is defective or not, I've decided this exhaust is not for me and I'm putting stock back on. Hopefully, the buzzing will go away and I'll know it was the exhaust and will deal with it that way. If not, then something else will get corrected and I'll have NISMO exhaust for sale.

 

I would only hear it vibrate around 2000 rpm to about 3500 rpm if I remember right.

 

Wow! Seriously ? I love this exhaust. It sounds sooo incredibly good. I cant believe you dont like it.

Of course I never had that rattle problem but sheesh goin back to stock is kind of exteme (unless your an old lady or something). No offense!

 

If you sell the exhaust, get the Injen. No rattling here..Just sweeeet sounds!

 

Yup, that's where I'm at right now. Have a 400 mile road trip this weekend; will take the car. THAT will definitely convince me whether I want to keep it or take it off. I think I need to sit back and think about it some more. Like, when I just left to pick up my wife from work, I was driving thinking "...what am I thinking..." So, needless to say, I'm a little indecisive at this point. I think b/w the rattling, my CF hood coming in totally damaged, and all I just need to take a step back. But at this point, I'm leaning more toward going back to stock than not. Like I said, this weekend, 2 1/2 hours each way, will help me decide once and for all.

 

Thats cool but the highway is hardly the place to decide. Its the quick bursts around the side roads when you will miss that sweet tone.

 

OHHHH....be quiet!! That's what got me second guessing myself this afternoon...top down, on the twisties, giving it the throttle and hearing it sing...do you not see how tough this is for me?

You got to understand this is all new, modding cars that is. I'm 41 years old and doing stuff that I never thought I would do. Then when I finally do, I have these annoyances to deal with that makes me question why I didn't leave well enough alone...then I take a drive like I did this afternoon to get my wife...it truly does sound awesome.

But I gotta see if I can deal with the highway tone, too 'cause that's where I spend 60% of my time in this car. If I can live with it this weekend, then I may just stick it out and make other adjustments...maybe the cats just need to go back to stock?

 

HAHA! Actually I am just a little older than you. I dont have HF cats (yet) but I am told they make it a fair bit louder. However, the Z is also an extra car for me so its not a big deal for me. But I do love the sound. Keep it!

 

Ha...well, it was supposed to be extra for me, too, but I ended up making it a daily driver...just too hard to pass up. I do intend to drive my Frontier more, especially in the winter, though.

Anyway, if it is the cats that are rattling, which who nows at this point anyway, I may just go back to stock cats before I ditch the entire exhaust. With you not having all that done and giving me a sense of what yours sounds like on a highway run...makes me think I need to undo something else before I toss the entire exhaust. Well, anyway, I'll know in about a week what the issue is and will take it from there.

...it does sound good, though