Had a fun night wrestling the exhaust last night, installing my shiny new Cobb Catted Downpipe and Cobb Catback. Forgot to pickup a tool for the O2 sensor so after much struggling I ran next door and borrowed a 22mm wrench. Besides that it was a pretty smooth install. The sound and feel is AMAZING, worth every penny. Can't wait to get this leak fixed so I can really romp on it. The leak is coming from the joint where the downpipe meets the midpipe, where it used to be a flexjoint on the stock exhaust but it seems Cobb's design isn't intended to flex much. I used the springed bolts off of the stock exhaust (was actually an STi stock turboback I got free) and installed them as directed but I can't get the joint to sit completely flush. The leak is on the driver's-side of the fitting, and no matter how many times I loosen every bolt on the entire exhaust and readjust everything it just won't seal. Any advice? Should I just buy some gaskets to stick in there or what? The leak isn't bad but it's enough for me to hear noticeable engine noise when standing on the left side of the car. I swear it's like my turbo is facing 4-5 degrees too far to the left, I had the same problem when installing the STi exhaust. I think I'm going to go buy replacement springed bolts at Advanced since these got pretty roughed up by my cheap tools. Still stoked as hell about the exhaust though - couldn't be happier with the sound volume & tone and the massive performance increase. Thanks for any help -- Justin
Well it came with a gasket for the midpipe-catback junction but not for the dp-mp, and there wasn't one on my old exhaust :eek3: Can I find the right gasket locally? <noob
Definitely get some gaskets. Make sure its for a 3" pipe or 2.5" if its the STi catback, OEM won't fit. Metal on metal doesn't make the best seal. Glad you are enjoying stage2, the top end is lots of fun. Try SOG or a local member.
Cobb's design is to mate with a stock intermediate pipe (or the Cobb exhaust). You can see the taper in the downpipe and in the intermediate pipe. Ditch the spring bolts, go to homedepot and find replacements and get new gaskets and possibly copper gasket sealer. For comparison, here is a quick video of my Cobb catback and my Godspeed downpipe. http://youtube.com/watch?v=nEaDiT1PKGA
Ahh thanks! I feel retarded, went down with a screwdriver and a hammer and pulled the stock donut gasket off that seemed to me to be welded to the pipe . This is all I should need, right? Besides replacing my crappy bolts. Just to double-check, there's no gasket between downpipe and turbo right? I'm very inexperienced and did this whole install alone. Nice video btw - I might make one of mine once I get it straightened out
you cant get a good seal an will eventually leak between a flange end and a donut end. you can try 1. face the donut opposite direction for now alternate 1. get an aftermarket int pipe that has flange ends 2. cut the existing pipe and weld a flange there and get some gaskets your stock IP is not 3" either and BTW every joint on an exhaust connection has a gasket
I am about to do the same install including an up-pipe. It was recommended I stick with OEM gaskets, based on the aftermarket gaskets leaking. It was also recommended I wrap the down pipe especially the cat. I having a seasoned tech doing the install for me and I want to supply the best parts available so I don't have to tear anything down after the fact. Any recommendations regarding the extra's...gaskets, exhaust wrap, hangers etc..
Well I put the gaskets on and retightened everything really solid and it's still leaking a little. Any reason I shouldn't drive it hard like this besides it sounding annoying? Again it's the joint right behind the O2 sensor and its leaking down towards the road now so I don't think it'll hurt anything. Hopefully next weekend I'll figure out a way to fix it :squint: Thanks for the info
No .. you should be drive JUST fine. ive had a leak near my mid pipe for the last yr and a half ..lol
Well, an option would be to replace the hangers. Another trick would be to hold the intermediate pipe level to the downpipe (with your chest or what not), while you tighten them both together. Ive found that it helps to tighten the left a few turns and then the right a few turns until both are fully tight
It is a metal crush gasket. Yours might have gotten stuck to the turbo. Check the old DP and see if ther eis ametal gasket still stuck on it. You would have a massive leak there without a gasket.
Yea I can hear it leaking at the DP under boost now. I'll run to SoG first thing tomorrow and get the gasket. So for the other leak I should turn the donut gasket around backwards and have the intermediate pipe completely loose as I tighten? I wonder if I would end up having to put a lot of stress on the IP>catback joint this way. Worth a shot - is everyone else just using the stock donut gasket at this joint? Seems like there would be a simple better alternative. Don't see why Cobb couldn't include any gaskets or even mention them in the directions for a $1200 purchase :/ Thanks
copper sealant will be required the donut has a taper side --> 3" O with copper sealant you are trying to wedge it tight (seal) the donut square side --> 2.5" IP w/ cu sealant again tyring to use the conical side to wedge a seal depending how well you line up and if donut is not damage - this MAY work as a temporary fix only this is by no means a permanent fix. im sure you like your car so why rig it
I don't know if there needs to be some flexibility in the coupling or it is not enough of a clean fit, but I would consider running a bead around that thing and be done with it. Weld it! You should also consider prior to any permanency wrapping that down pipe and retaining the stock heat shield or getting an after market one if Cobb did not supply it. I am about to do the same install and have been doing much research. Apparently allot of people are melting their CV joint boots and power steering lines because the heat is so intense. This is per a Subaru tech.