just got my midlength dp and headers from zzp on my auto cobalt 2.4 installed. at idol and up to 3k rpms it sounds amazing. but as soon as it goes any higher i hear a vibrating noise. i took it back to the guy who put it on and he hit the pipes with his hand and heard no noise. obviestly the bolts holding it to the car are solid but what could be making this noise? i am not sure if this is how its supposed to sound it sounds like a VW. not sure if he took the heat shield off.

similar problems?

 

can you make a decent video?? id be interested in how sounds

 

i can try. i will try to get a vid up tomoro night

 

its a hard noise to describe it like is a buzz/vibration after 3,500 rpm

 

only a vibration above a certain rpm?

I know the manual pipes can rub on an auto cars swaybar.
But id just check any shielding and make sure theres enough clearance all around the pipe remember that pipe will move some when the cars given throttle.

 

Correct at about 3,500

 

you sure its not leaking? if its the older style that bolts the dp to the header its probably leaking there.

 

The 2 bolts were prone to leaking. The v bands are supposed to be a lot better. Should be fairly easy to hear if its leaking. But I'd get under the car and give it a good looking over.

 

It has the v band. And I will get undernieth it tomorow.

Btw I drove it again and the more I hear it the more I'm convinced that it's coming from the back of the car. Any chance my catback could have been set loose on a hangar? Or maby the new dp/header causes more vibrations than before.

Also I checked and the heat shield is still there

 

Muffler breaking apart?

 

flux capacitor kicking in?

 

i have the same problem with my dp from them but after i drive a little bit the noise goes away.

 

I looked under the car today and every bolt is tight and nothing is loose. The only possible thing I can think of is the heat shield by the cat. I have the vibrant j hook defouler and its like 1/2 inch from the heat shield

 

If its the heat shield under the floor of the car in the exhaust tunnel you can massage it in a bit to give it more clearance if you think it might be rubbing. Otherwise it could be an exhaust leak. But thats the only 2 things I can think of. Exhaust leak or its rubbing on something.

Off topic but how do you like the LSJ throttle body?

 

I like the lsj tb it added noticeable throttle response.
Anyways the zzp dp/header is brand new and my corsa catback is only 6 months on my car. The catback wasn't making the noise before the dp install so I can rule out a problem with the corsa. And I doubt a new dp/header is leaking. Is it a possibility to remove the heat shueld completely

 

im gonna say its just rasp/cylinders firing more audible from better/larger/thinner parts

if its a leak, it'd be audible at idle/low rpms too, start it(when cold if possible), pop the hood and stick your head in there over/near the header and listen for ticking. and or put it on jacks/ramps and do the same thing to check the dp/cat back for noise

 

Have a friend rev it for you while you listen and see what you think.

Rootbeer could be right it could just be rasp. Didnt think about that... my slp was very raspy above 3000 rpms with the shorty header and a zzp downpipe (was a 2.5 going to try a 3" to 2.5" and see if that helps... probably not lol) But its not right now due to the stock downpipe being back on (the zzp rubbed on my swaybar so it came off).

Good to hear about the lsj tb.

 

I will try to get a video up.
Also is it ok to remove the heat shield?

 

I just bought one of these combos and I'm curious to see what the problem might be as well. I have the stock exhaust though.

 

i threw away my heatshield when i put my header on lol

 

Probably header leak.

 

it just got put on im almost positive that nothing is leaking.

i think its the cat because when the car heats up after driving for like 15 min. it dosnt make as much noise.

 

Cat?

 

What he said^^^

 

more than likely, it was there high flow cat. the noise started when i put it on and it still makes the same noise to this day. i just took it as the "breaking in" procedure