Installed LTs. Weird sound

[Ssiptang]

Installed Pypes LTs and X pipe over the weekend.
Perfect fitment.

But now I'm getting this weird swoosh sound coming from engine area and underneath the car. It almost sounds like water going thru the hose. like shhhhhh sound if you know what I mean.. Maybe its the freed exhaust flow?

Also, it sounds amazing under normal driving (extremely loud tho) but under hard acceleration around 2.5K~3K, it is raspy as fuuuggg...

To get rid of the rasp and to tone it down a bit, If you had to choose between 1. swap it with O/R H pipe 2. add high flow cats to existing O/F X pipe, which will it be?

I have a pair of HFCs sitting in my trunk already.. I can always exchange them with a h pipe since they are priced about the same.

Thanks for your inputs

 

[HellsBells]

If it's a hissing noise on idle, it might be an exhaust leak. You can make sure by spraying some WD-40 along the clamps and stuff and then idling the car (ideally on a lift) and see if the WD-40 bubbles up near the clamps. If it does, you make have a leak.

 

[UltraKla$$ic]

X-pipe FTMFL!!!!!!! Toss that shit in the garbage

 

[HellsBells]

X-pipe FTMFL!!!!!!! Toss that shit in the garbage

I don't think the Xpipe is causing the swoosh.

 

[Ssiptang]

If it's a hissing noise on idle, it might be an exhaust leak. You can make sure by spraying some WD-40 along the clamps and stuff and then idling the car (ideally on a lift) and see if the WD-40 bubbles up near the clamps. If it does, you make have a leak.

Yea it sounds like hissing noise.
I might have to try that. I tried to feel the leak between the clamped area and flanges with my hands, but didn't feel any leak though..

 

[UltraKla$$ic]

I don't think the Xpipe is causing the swoosh.

The rasp is what I couldn't stand. I'll sacrifice 1hp. Lol for the H pipe.

If you trace the swoosh down to bein an exhaust leak use the Percy Seal-4-Good exhaust gaskets and be done with leaks.

Good info given on tracking the leak too btw!

 

[HellsBells]

Yea it sounds like hissing noise.
I might have to try that. I tried to feel the leak between the clamped area and flanges with my hands, but didn't feel any leak though..

It's usually really small, too small to feel with your hand anyway. You also have guts putting your hand near the exhaust while the car is idling. Try the liquid spray method, obviously, do it when your car is still cold and then fire it up. You could also use a cigarette or something to see if the smoke gets blown in a certain direction from the pipes too.

The rasp is what I couldn't stand. I'll sacrifice 1hp. Lol for the H pipe.

If you trace the swoosh down to bein an exhaust leak use the Percy Seal-4-Good exhaust gaskets and be done with leaks.

Good info given on tracking the leak too btw!

Ah gotcha, agreed on that one. The H-pipes sound much nicer in my opinion. 5-10hp difference are negligible in my opinion. It's like the difference between if you ate breakfast or not. Or if you wear nothing under your nomex suit...tee hee hee....

 

[Ssiptang]

So you guys don't have that hissing shhhh sound at idle right?

 

[Mach1Run]

Pypes LT and X here and I know the sound you're talking about. I swore I must have missed something and had a leak but I asked the shop in town to listen and they seemed to think it was normal. I love the X I have on my mach but wish I had gone with the H for the GT.

 

[Aandf1978]

I have Pypes LTs and Pypes Hi Flow Catted H, I have never heard the sound you are describing. Go with the Pypes H Pipe and weld in the Hi Flow Cats!!! I think you will love it!!

 

[Ssiptang]

Pypes LT and X here and I know the sound you're talking about. I swore I must have missed something and had a leak but I asked the shop in town to listen and they seemed to think it was normal. I love the X I have on my mach but wish I had gone with the H for the GT.

Seriously.. I do wish I had gone with the H too. This rasp is just too much with off road X pipe.
I'm just going to weld in a pair of cats and learn to live with it. Maybe it'll grow on me.
I also read from somewhere cant rememeber but It was normal to get increased exhaust flow sound after LT install. Just couldn't find the thread or article so I had to ask to be sure.
Thanks for your input.

 

[Ssiptang]

I have Pypes LTs and Pypes Hi Flow Catted H, I have never heard the sound you are describing. Go with the Pypes H Pipe and weld in the Hi Flow Cats!!! I think you will love it!!

I'm going to stay with X for awhile untill I find a good deal on used H pipe.

 

[fst06stg]

i have a hiss, but not at idle. mine does it when im cruising and i let off the gas. i think this may be the free air flow sound youre referring to.

 

[HellsBells]

I've done some extensive exhaust work on many cars and I can't say I've ever heard a "hiss" being a sign of higher exhaust flow. In fact, there's no way you can really tell if you're getting more flow or not based on sound. After all, the "flow" (I use this term loosely, as everyone else I presume) of the exhaust is affected by heat, pipe sizing, outside temperature, RPM, natural aspiration or forced induction, the bends in the pipe, the firing order, etc.. etc..

The point is, there are way too many factors and going off by sound would be like judging a stripper based on the song she's dancing to.

My vote still goes for exhaust leak based on your description of the hissing noise.

 

[Ssiptang]

I've done some extensive exhaust work on many cars and I can't say I've ever heard a "hiss" being a sign of higher exhaust flow. In fact, there's no way you can really tell if you're getting more flow or not based on sound. After all, the "flow" (I use this term loosely, as everyone else I presume) of the exhaust is affected by heat, pipe sizing, outside temperature, RPM, natural aspiration or forced induction, the bends in the pipe, the firing order, etc.. etc..

The point is, there are way too many factors and going off by sound would be like judging a stripper based on the song she's dancing to.

My vote still goes for exhaust leak based on your description of the hissing noise.

I will definately try the liquid spray method you've mentioned.
Thanks for your input.

 

[HellsBells]

I will definately try the liquid spray method you've mentioned.
Thanks for your input.

No problem. Also, if you WD evaporates too fast, windex is one I like to use too because it bubbles up easy. If you can't figure it out and aren't too bothered by it, you can take a brush and clean your exhaust pipes up to get all the crap off and just drive it for a couple hundred miles. You should see black soot build up near the leaks.

 

[bigmachano]

you'll never get rid of that rasp. i have jba longtubes with a mac prochamber and its still there, but i've learned to love it. originally had the longtubes with an offroad h setup and it was much worse, the prochamber helped a lot, but its still there under hard acceleration.

 

[Mach1Run]

I have the high flow cats in too and it doesnt make enough difference to make it worth the money, unless you have to have them for inspection like I do.

 

[PoonStang GT]

i have a pypes o/r x and i know exactly what you are talking about. sometimes if u get on it on the lower rpms you can hear the swoosh very well. i have no leaks by my xpipe and when someone revved my car while on a lift u can tell that the sound is just resonating off of the pipe.