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Downpipe Installed, Small problem

7.1K views 32 replies 17 participants last post by  wrecks43  
#1 ·
I just recently installed my Perrin Catted Downpipe, and flashed Cobb AP stg2.

I love the new power its awesome, but i think i have a small problem. Every time i'm stopped and start going, when i have the clutch almost fully out there seems to be a small clanging noise/feel. And i THINK its only from starting when stopped.

Also, i'm not sure if this is anything, but when i start my car it feels different when the engine is igniting, not sure if thats normal with a new DP.

Any ideas?
 
#3 ·
Yeah, i know the engine sounds quite different due to the exhaust, it just feels different when i turn on the car.

And maybe i only get the rattle at very very low RPMs...

Oh, and i think he had to uninstall the stock heatshield to fit the new downpipe... should i think about getitng a new one?
 
#6 ·
Yes if you want your intercooler to be colder get a heat shield!
Is it worth the 50 bucks?
 
#7 · (Edited)
here's a pic straight from cobb's downpipe installation instructions... it shows two options... trim where the black line is. do yourself a favour and save $50! :) .. you might even come up with a better trim pattern to save more of the heatshield.

Image
 
#8 ·
u might wanna check the rest of the bottome of the heatshield i came wit the same rattle problems and it was the rest of the heatshield goin downward.... just unscrew it, and i didn't put my heatshield back on just left it showin the Invidia part.... all i get is a engine check light, probably cause i have no cats now so if anyone can help me wit it, instead of me disconnecting the negative battery all the time i would appreciate it but i'll keep lookin the forums to see if anyone has an answer for it.....
 
#9 ·
I just went catless over the weekend. I also got a rattle that only made itself known when the engine shuddered during startup or shutdown. Figured out that the probem arose from the aftermarket DP being about an inch shorter than the stocker. I had to pull my catback forward to mate up with the new DP which in turn caused the rubber exhaust mounts to rotate forward and up, thus raising the catback about half an inch. This left the catback resting against a bolt on the bottom of the car, causing the aforementioned rattling. As a temporary fix I taped a thick piece of rubber to the offending bolt to provide some cushioning between it and the catback. I just ordered kartboy long exhaust hangers from OAKOS, who has free shipping on all kartboy products btw.:) Here's hoping that it is something easy. Good luck.
 
#10 ·
Ok just took my car for another drive, and the rattle/noise is starting to get fiercer. It starts to get pretty bad rattle at around 4500 rmps, and when i put in the clutch to shift semi aggressively (and normal, but worse when aggressive) the rattle gets even worse than when at 4500 rpms. It gets worse as you go up.

I pulled the car over, opened the hood and stared down to where teh DP is connected, it wasn't loose anywhere, so the DP seems to be pretty securely put.

My guess is that it HAS to be rattling up against something causeing a kindof hard core vibration. It just doesn't feel right.

Any thoughts/ideas/solutions would be greatly appreciated.





PS.

Sucks so much to anticipate a new part only to get problems with it. (It has to be a shoddy install, its a high quality company/part: Perrin)
 
#12 ·
Did the rattle or noise start right after your install? As Yossarian mentions, did you check the rest of the exhaust system. Perhaps somewhere the tubing is coming in contact with the body. Does it only occur on throttle, engine moving?!? Maybe the material inside in the catted down-pipe has come loose (highly unlikely though)

I would concentrate on the exhaust making contact with the chasis.
 
#13 ·
if you have the same problem i did it wasnt an issue with just exhaust as soon as i put my uppipe on the bottom of my cobb heatsheild rattled against the uppipe.seeing you already have an uppipe the cobb heat sheild wont do you well.
 
#14 ·
No, i don't have an uppipe... or a heatshield at the moment.

But, i talked to the guy who installed it and he said if he remembers correctly that its vibrating against the "Transmission Crossmember"?

And it only rattles on me when i'm in high RPMs. 4k and above it starts to get pretty bad.

Any ideas on a solution?
 
#31 ·
I had this same problem after I installed the STI gruppe N trans mount. You have to remove the bolt holding the DP in place and if youre not careful you can have the DP vibrating against the trans crossmember when you reinstall the mounting bolt. You just have to loosen the bolt holding the DP in place, pry the DP away from said crossmember and retighten bolt. The noise should disappear.
 
#15 ·
drummerboy said:
here's a pic straight from cobb's downpipe installation instructions... it shows two options... trim where the black line is. do yourself a favour and save $50! :) .. you might even come up with a better trim pattern to save more of the heatshield.

Image

i just got this one
Image


HERE
 
#17 · (Edited)
Yep thats exactly where it is.

I went under my car today to have a look, and the guy who installed it had to cut a little bit of the xmember to even make the DP fit. He only cut a little bit off because he didn't want to do anything too radical, which is completely understandable.

(There is barely any room between the cross member and the DP in only one small section btw.)

Now that we know its vibrating against the xmember, any one have any ideas?
 
#18 ·
bump...

i am also interested in hearing more about this problem/solution...

my perrin catted dp is coming in 2 days... sorry to hear about the problem snowave6... i hope this isn't a common problem with this dp (since it did just come out).
 
#19 ·
snowave6 said:
Now that we know its vibrating against the xmember, any one have any ideas?

ya, buy the long exhaust hangers from almost any online store..
or you can go the cheap but harder way.. and drill another hole in the mount on the downpipe, so that it mounts away from the xmember and stays.
 
#20 ·
Thats good news. SEems to be quite an easy fix to the problem. Are the any downs to getting longer exhaust hangers? Does it hang too low?

How do i tell if the exhaust hangers i order are the "long" ones.

Thanks for the help.
 
#21 ·
#23 · (Edited)
Hopefully this will drop my exhaust down about an inch and fix the issue.

Just ordered them from that site. (thanks le wagon)

And thanks all for the needed help.
 
#24 ·
Will new hangers fix this problem for sure?


I'm going to talk to the installer tomorrow, will bring the new hangers. I can't imagine Perrin making a part that would require any cutting on any wrx.
 
#26 ·
I would assume so... he's a pretty experienced guy (the guy who installed it).... although he isn't a subie specialist.

I'll check with him tomorrow and update you guys.

Thanks for the help subie.