Headers are in but strange noise from the Tail

F

FXtion

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Location
sherman oaks, ca
Managed to get the DC headers in today after about 14 hours of work. Let me tell you if you don't have every combination of tools and Extentions with in reach, do not attempt it. Also, if you don't have the patience of turning a nut on a 1.5 in bolt 1/4 turn at a time for over an hour, working in an area smaller than the palm of your hand, DO NOT Attempt to do this yourself. Make sure that you have purchased new Gaskets, and 12 flange nuts from the dealer. Unlike what you might think, they are not M10 metric nuts. The thread is different.


Anyway, now that I have them on, there is strange noise coming out of the nismo tail pipe, anyone knows what that might be.

Also, I'm prety sure I need to reset the ECU and do a Air flow reset, right?
 
from what I've seen when I did my headers, the headers alone do add quite a bit of rasp to the exhaust, going back to stock cats helped a lot, without cats it's really horrible, but even with the cats you'll get slight raspyness... I'm guessing that's the noise your talking about.

yeah, the headers are a ton of fun to install, patience is one of the things needed to install them, & yeah, a nice selection of tools... I feel your pain when you say one nut can take an hour... the really fun part is, after you get them off & feel like your half way there, you then start to realize it's even harder to get at the bolts for tightening with all the tubes in the way of the headers... there harder going back in than comming out:smile:
 
turbocad6 said:
from what I've seen when I did my headers, the headers alone do add quite a bit of rasp to the exhaust, going back to stock cats helped a lot, without cats it's really horrible, but even with the cats you'll get slight raspyness... I'm guessing that's the noise your talking about.

yeah, the headers are a ton of fun to install, patience is one of the things needed to install them, & yeah, a nice selection of tools... I feel your pain when you say one nut can take an hour... the really fun part is, after you get them off & feel like your half way there, you then start to realize it's even harder to get at the bolts for tightening with all the tubes in the way of the headers... there harder going back in than coming out:smile:
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I think they deliberately made it impossible to get to the middle nut. It seems there is no "modern" tool that will bet in there and turn. You have to turn the nub a "hair turn" at time. I used Stillen's instructions as a guide and let me tell you; the line "SOME PATIENCE IS REQUIRED" is completely an understatement.:mad:

As it turns out, the noise is not coming out the back. When the car is at idle there is no abnormal noise of any kind, but when you rev it up, there is a Hissing noise that comes straight out of the Air Intake and you can hear it through the filter.:confused: It almost sounds as if it's Gasping for AIR :eek:

There is a little bit of Raspyness to the sound now but (I'm quoting some one in :iS:) it does not sound like a "Ricer". I actually like it.:smile:
 
rookie said:
What kind of noise? When I put DC headers on a friends G, it came with new nuts. I believe it is a M10x1.50 vs M10x1.25?
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we took the originalls to three different places and there was not a single bolt, Metric or otherwise that fit them. The M10 would trun to the tip of the nut and then would stop, where the original bolts, that are on the engine would allow you to hand turn the nuts all the way. I did not want ot take a chance and sine the Dealer's parts dep. is closed on Sunday, I had no choice to use the originals. That's what you get when you buy used. I did however use brand new Nissan Metal Gaskets.
 
AAAaaaaaa.....

There is something definitely wrong. When driving uphill or in the freeway, the exhaust changes sound, and there seems to be no torque. It almost sounds as if the car's got laryngitis:frown:. I also noticed that some how the Nismo Exahust has moved about 3/4 inch back. I'm prety sure that everything was bolted back.

Could it be rattling??? It sounds so restrited. Could it be the the mid-pipe gasket blocking part of the flow??
 
When I got my headers put on - pushed the rest of the piping back just a tad.
The Mid pipe was making contact with the rear crossmember and it was rattling.
I took it to a muffler shop and they fixed it for me, but your symptoms dont seem like its a rattle.
 
I may have used the right word, the Ehaust tips used to stick out about 3/4 of an inch, but now they are about a 1/4 of an inch out. I gues I should have said, they are pushed in, not back.

IMGP6661.jpg

(this is what it looked like before, I don't have after pics, yet)

Also, there is no way for me to check if there are any leaks. The sound only seems to be there under stress. Even if I rev it up to 4-5k there is no sign of leakage. :confused:

I'll have to find a place where I can put it on a roller and while it's up on a jack. Like a dyno shop except one that either has pit or is raised.
 

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fothion said:
AAAaaaaaa.....

There is something definitely wrong. When driving uphill or in the freeway, the exhaust changes sound, and there seems to be no torque. It almost sounds as if the car's got laryngitis:frown:. I also noticed that some how the Nismo Exahust has moved about 3/4 inch back. I'm prety sure that everything was bolted back.

Could it be rattling??? It sounds so restrited. Could it be the the mid-pipe gasket blocking part of the flow??
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Its funny you mentioned the mid pipe gasket. When I bought my Nismo from a my350z.com member he had used a mid pipe gasket with a smaller opening and when I took it out, it had a black ring around the smaller opening. He also complained that his exhaust was too loud (he was running with test pipes and headers)

hope you can find your noise problem.
 
Yeeeehaaaaa!!!!!

The problem resolved.

It seems that there was about $70 stuck somewhare between the Cats and the resonator. :wink::laugh:

It turns out that the DC headers are not only stlightly shorter, but thy are slightly pointing downwards. They change the angle of the Cats just enough to cause the Y-pipe to sit lower. Once you connect the mid-pipe to it, the resonator will rest about 1/4 of an inch lower that where it should. Once the car is moving at a higher speed, the combination of the road condition, the resonance of the exhaust system, and the movement of the engine causes the resonator to rattle against the metal brace directly underneath it. So the Noise was coming from the resonator hitting the the metal, and I'm happy to say it was not Larangitis.:top:

What we had to do was to open all the bolts from before the Cats all the way to the back of the extension pipe, and re-tighten them with a jack under neath each peace as we moved back. Also, i made sure that I adjust the gaskets each time so the Inner holes match exactly so there is no overlaping. Once done, there is enough clearance for it not to hit. And the POWER is Back. 120 in 3rd gear is no longer an issue. :listen::tongue:
 
StuLax18 said:
so what was causing the lack of power? something not fitting right?
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I'm not sure, what ever it was is not there anymore. It may have been the gaskets not aligning the holes, or the pipes may not have been totally though. The power is back, but the MPG is gone. I know it was too good to be true. went from 14 to 17, and now back to 14 again:frown:

I
 
turbocad6 said:
from what I've seen when I did my headers, the headers alone do add quite a bit of rasp to the exhaust, going back to stock cats helped a lot, without cats it's really horrible, but even with the cats you'll get slight raspyness... I'm guessing that's the noise your talking about.
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Turbo,

Wich mod did you do on your cats wich you didn't like...?? I now have the DC headers on as well with the Kakumei Y-pipe and am thinking on changing my cats as well,but then with metallic cats and no dummy's or so. But am doubting as i do not want the sound to change that much and give it a more "Tin" sound. But do think i need it to get more out of it as for performace.

Any suggestions...?? ( of course all suggestions from everyone are welcome )
 
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