Hey guys,

After installing a pair of CrawfordZ HFCs (used) and an Intense Power Y-Pipe on my stock exhaust, I've been getting a really odd sound. When I get around 2500-2800rpms, the exhaust almost sounds 'tinny', as I have no other idea how to explain it. It isn't a rasp, but just an odd sound, and it doesn't sound good. Once I pass 2800rpms, it sounds AWESOME, but for those few hundred RPMs (which you constantly go through), it does not sound good one bit. I THOUGHT that it was probably the y-pipe due to the bottleneck, but now I'm questioning whether or not it's the HFCs? How in the hell do I find out what it's coming from? I really want to get this fixed ASAP, so your help would be greatly appreciated.

`John

 

Hmmm... if you're completely positive its not rasp, then im not sure what it is. You can make sure all the bolts & nuts are torqued tight enough, but I doubt that's the case.

It might be normal as your modifications have changed the flow of exhaust gases. I really can't help you unless I actually hear it

.

 

I don't believe it's rasp, unless my definition of rasp is different, lol. Care to explain to me what it would sound like if it were rasp?

 

Rasp = tin-like sound. It doesn't have to sound obnoxious. At part throttle, it sometimes sounds like a high pitched drone. At WOT, well, its pretty obvious. I'm not sure how else I could describe it.

 

It might be rasp then. Would that be from the HFCs or the y-pipe? I was thinking about removing the y-pipe. As I mentioned in another thread, there is a weird 'whoosh' sound which we checked out that comes near the back portion of the y-pipe which connects to the mid-pipe, so I just figured that THIS sound was due to the y-pipe as well?

 

The whoosh sound you hear might be two things:

1) It could be a leak. If so, check your gaskets.

or, most likely,

2) Just a normal characteristic or a more-flowing exhaust.

Does the "whoosh" sound happen almost emmidiatly after the revs start falling back down on a stand still rev? If so, then it might be #2. It's very obvious on test pipes, and its also there on HFC (although not as obvious). This sound has nothing to do with rasp or drone though.

.

 

Yeah, it happens when the revs fall down. However, I believe I hear it sometimes when I floor it, but I can't be certain.

As for the rasp, what do you think is contributing to that? I hope it's just the y-pipe so I can just yank that out and put the OEM back in, because I'd prefer to leave the HFCs in.

 

If that's the case, I wouldn't worry about it too much. It's most likely normal. Mine does it all the time, and its pretty obvious.

It could be a combination of both. I would definately leave the HFC on though. You could maybe speak to 'ShanesG' as he has a stock exhaust + HFC. Here's his video of a standstill rev. He seems to have some rasp, but its nothing crazy. Also, notice how he also has the "whoosh" as the revs fall down. It almost sounds like a whisper.

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Yeah that's the whoosh that I hear, when it's almost coming back down to idle in the background. However one other thing to note, the "rasp" or whatever sound that I hear around 2500-2800rpms does NOT occur when I'm just revving it either in P or in N. It only happens when I'm actually driving and in gear, increasing my RPMs.

It just sucks because I already paid $75 just to get these installed, and I don't want to have to pay another $50 or whatever to get the y-pipe uninstalled, and end up having the sound still there. I really don't want to keep wasting my money on these installs, because it's ridiculous. So I want to try to narrow it down first before I do anything. By the way, thank you so much for your help, I really appreciate it.

`John

 

i would chalk it up to putting a 3" outlet y pipe up to the smaller stock midpipe. the y pipe would be much easier to change to see if the noise goes away. just 6 bolts and put the oem back up.

 

Yeah definitely. So I listened to it more carefully on my way to work today, and what it sounds like is vibration/rattling between 2500-2800rpms. Any ideas?

 

could it be described a buzzing noise? along with the y pipe's outlet being too big, i would bet they used an unlined flex section in the y pipe mainly based on the price they sell it for. an unlined flex section can sound like an air leak but it could occur at just about any rpm, maybe its just noticeable in the range you gave.

 

Buzzing noise...hmm...

Not sure about buzzing noise, heh, but I'd have to listen to it again.

BTW, someone else mentioned that the heatshields may need to be bent on the CrawfordZ cats. When I take the car to the shop, do I just tell the guy to bend them and he'll know what to do?

 

bump

 

wow... this has gone from woosh to buzz to rattle... I'm not trying to be a jerk but from the first post this was something that can�t be diagnosed in a forum.

I suggest finding a reputable aftermarket friendly mechanic or knowledgeable enthusiast that knows our car and have a listen... otherwise you could really go on for days/weeks with the theories...

I've often wondered if people post bogus "sound descriptions" just to see how long the thread will go... (not suggesting this is that).