Strange sound after exhaust install, please help identify.
 

I had my corsa exhaust installed yesterday and it sounds great. Took it out today for a longer drive and noticed once it warms up i get a strange sound at exactly 2400 rpm in all gears. Its like a high pitched screeching sound, the closest thing i can think of is when someones brakes are worn out. That screech kind of sound. Its most noticable when im off the gas and the revs are falling. If im going down a hill and the revs are holding right in that 2400 range it will continue to make the screech. I also noticed when i shut the car off it made a squeek when the exhaust vibrated from shutting down.

Whats the most likely cause of this? Is it something that will go away as it breaks in? If i get it back on the lift what should i be looking for?

Mine didn't do that. Sure it's not a leak?

I'd have the person who installed the exhaust check the usual suspects:

* exhaust leak at the connections

* see if part of the exhaust system is touching a part of the frame

* check for a lose hangar

* check welds for exhaust smudge (leakage)

If you don't see anything obvious, Bubba says to fire it up, while it's on the rack, rev to 2400 rpms then beat the hell out of it with a big rubber mallet till it's quiet ........ :paddle:


humfrz

Well, now THAT was a big fucking help !!....... :slap:


:D



humfrz

But hey Humfrz? You did hear it coming?

It only happens after the exhaust heats up a good bit. Does that point to one thing over another?

Ok if i grab the pipe leading into the muffler and give it a shake i can hear a squeek coming from towards the front of the car. I can imagine if its vibrating fast that squeek could be the screech i hear. What would squeek like that? A hanger? Would spraying with wd 40 help?

The flange between the mid pipe and front pipe has a donut gasket. That can be hard to get perfect and may need some adjustment. Tighten the spring bolts a couple turns and if that doesn't work LOOSEN them a couple turns.

I helped a friend install a catback and it took a few tries to get it perfect and get rid of the noisey leak it had.

The donut bolts are spring loaded though. You tighten them all the way until they bottom out and then torque them to spec. Tightening them more than that has no impact on the donut because it’s just springs putting pressure on it. The only way to make it tighter would be to shim the springs or get stiffer springs.

@guybo and @ermax, you're both wrong. Maybe don't give advice if you don't know what you're talking about. The Corsa does not use the donut gasket, it uses a flat gasket.

For what it's worth, my Corsa does the same thing at around 2k or 2100, it's rubbing close to the rear subframe, and have just been too lazy to do anything about it.

It's possible to over tighten or unevenly tighten them. It probably wouldn't whistle but it's worth a look

I am not familiar with this exhaust. Guy made reference to donut gaskets which was what I was responding too. No need to be such an ass though. In my short history on this forum I’ve noticed that 100% of your comments are douchey. You only respond when you find a chance to be a douche. Handclap

Good point ......... but, DANG.....the way you say it ........ :(

Remember, the shelf elf is watching you ....... :D


humfrz

If part of the exhaust system is rubbing on another part of the car ..... WD-40 would, at best, be a temporary remedy.

You should find the root cause ...... then separate the offending pieces.

Yep, Bubba style ....... a crow bar and some baling wire ...... ;)


humfrz