Hello Everyone

After do lots and lots of searching, with no answer, I'm now reaching out for help.

I installed Reso Test Pipes, Magnaflow X, and X02 catback. I've gotten the nasty whistle explained.......

http://www.zcar.com/forums/read/5/1805863
and
https://my350z.com/forum/intake-exha...oll-video.html

Has anyone come to a definitive solution to this problem? or does anyone have any suggestions to fix this?

**Edit**
I've already got new gaskets in place, I just need to know if I need to get my hands on anything else to get rid of the sound.

 

Yea, put you stock exhaust back on.

 

I thought the TD exhaust takes out the Y-pipe and has its own pipes going to the TP.... I think take out the magnaflow :/

 

After seeing the info posted about the Magnaflow, I doubt that it's the problem since there are some people without it are having the same issue.

 

I got it fixed with the Magnaflow X-pipe installed. However, it is not really a fix, it just silence the whistle noise with the build-in resonator. I can still hear it slightly under full throttle, but still much better than before.

In your case, if it is still very loud. Check carefully for exhaust leak or any damaged/cracked exhaust components first. Also, make sure all the welds are good, *sometime* the muffler exhaust may missed a spot and causing the exhaust leak.

 

Test pipes make strange noises you know that. The solution is OEM catalytic converters. Definitely.

 

You may want to check out Motordyne test pipes...

 

Thanks I'll take everything down and check for leaks on welds. Never thought of that

Yeah, but not the noises I want. I love the sound except for the whistle at 2k. It sounds like I have a slipping belt

Thanks.

 

Lower quality flex sections are capable of generating that type of noise.

 

I believe the hissing is due to turbulence in the exhaust caused by different piping diameters.

I've got the same sound when the revs drop from 2.5k to 2k rpms with HFCs on stock exhaust

 

I only know what I have tried myself. Hope this helps:

TPs + stock y-pipe + stock mid pipe + Greddy SE = very raspy

TPs + xyz-pipe w/res + stock mid pipe + Greddy SE= Rasp

HFCs + xyz y-pipe w/res + stock mid pipe + Greddy SE= No rasp but too quiet

HFCs + xyz y-pipe w/straight pipe + stock mid pipe + Greddy SE= Almost no rasp and best combo so far for me. Still fairly quiet at high speed yet deep at low speed.

I think RAYZ33 is right "...caused by different piping diameters" ...

My midpipe (2.75") and Greddy SE (2.5") may need to go. I kinda want to get a 3" exhaust from the y-pipe all the way to the back. But now I just want a 40" LCD tv... So for now Yoshimi will have to wait.

 

Thanks for the responses everyone.

I just ordered a few things I'm going to try with a shop local to me. Once everything comes in and I get to work, I'll post my results. I've ordered new flanges, new flex pipe, and all new gaskets. I'm going to get to the bottom of this.

 

**UPDATE**

Well the solution has been found. It's simple...............

Have the flex pipes removed, and just have the person weld in a regular pipe. That removed the loud whistling noise I was experiencing at 2k RPM when the engine was down revving.

I did however take a look inside the flex pipe, and it seems to have a liner like the flex pipe that is suggested. I'll post pics of that if needed.

 

hey, i think u bought that exhaust from me??? anyways, the problem may be the test pipes...those are obviously gonna free up some air/sound...which may be making that "sound" you dont like...anywho, keep us updated...

 

Yep that was me.

Like I previously posted, it's those cheap flex pipes. Once those were taken out, the loud whistle was gone. I'm cool with the hissing, but the whistle sounded like I had a slipping belt.

 

i was going to recommend wrapping your flex bung things heavily with some 30 $ exhaust wrap but you got it.

 

Wouldn't completely replacing the flex pipes eventually cause cracking at flanges and such? Since it can't "flex" at those joints when the car is under load and there's torque applied from the engine....

(Same concept as to why people request HFC's or TP's with mounting brackets welded on)

 

It can, but if you have been under there, there is some serious "play" on the midpipe side of the exhaust. Not so much on the cat side, but nonetheless, you could get away with it. Some friend's cars don't have a single flex plate. I think it depends a lot on the hangers used....

 

Well if you look around at some exhaust you'll see that they don't have flex pipes (Fast Intentions for example). Nobody has experienced any cracking with those exhaust, and the few others that don't. That was one of the key pieces of info I was looking for before I went this route.

I've gotten extra flanges, and got some better quality flex pipe, so if something breaks, I can fix it.

 

idk but if you look at the exhaust design i beleive the whistling noise is caused by that tube that runs up to the back part of the muffler. where it bends and goes up. try seeing if you can stuff a towl in it and see if it goes away. i hated the way it did that when i had my hks. but im pretty sure thats where it comes from.