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Hey guys,

 

I’ve been getting an exhaust type smell up around the drivers side window after putting on a used Cobb 3” downpipe I brought from someone here on the forums. Is this normal? I put the OEM Subaru downpipe on and smelled nothing, it’s only with this down pipe. I’m thinking a leak in welds or something? Everything looked good on the pipe itself and I made sure to get a new donut gasket and tighten the bolts where the downpipe meets the turbo. Any ideas would be helpful.

 

 

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Could be an exhaust leak, but also realize that whether it's a catted or catless Cobb DP, you'll have more exhaust smell from it because it's not doing the full catalytic convertor process that the OEM one does, so that the Cobb can recognize performance gains from less restrictive flow.

 

I have an invidia catted downpipe and even added a second high flow cat in my mid-pipe and I can still smell some exhaust with the windows down.

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Could be an exhaust leak, but also realize that whether it's a catted or catless Cobb DP, you'll have more exhaust smell from it because it's not doing the full catalytic convertor process that the OEM one does, so that the Cobb can recognize performance gains from less restrictive flow.

 

I have an invidia catted downpipe and even added a second high flow cat in my mid-pipe and I can still smell some exhaust with the windows down.

 

 

Thanks for the info! I wonder if I wrap it in heat shield tape if that’ll contain the smell cause It can get a little noxious.

 

There aren’t any down pipes out there that have a similar cat as the OEM pipe but an open mouth up top for the wastage?

 

 

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May be I'm used to it, but I don't smell anything with either car, both have Invidia Catted DP.

 

Do you have a exhaust leak further back in the system ?

 

Jack up the car, start the engine and spray some leak check fluid on the joints

305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD).  CHECK your oil, these cars use it.

 

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May be I'm used to it, but I don't smell anything with either car, both have Invidia Catted DP.

 

Do you have a exhaust leak further back in the system ?

 

Jack up the car, start the engine and spray some leak check fluid on the joints

 

 

I shouldn’t. I can confirm that this is happening only when I had the aftermarket pipe on the car. I think what I’m gonna do is get some pipe wrap and wrap the downpipe in it. From there, who knows [emoji2371]

 

 

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  • 2 weeks later...
Hey guys,

 

I’ve been getting an exhaust type smell up around the drivers side window after putting on a used Cobb 3” downpipe I brought from someone here on the forums. Is this normal? I put the OEM Subaru downpipe on and smelled nothing, it’s only with this down pipe. I’m thinking a leak in welds or something? Everything looked good on the pipe itself and I made sure to get a new donut gasket and tighten the bolts where the downpipe meets the turbo. Any ideas would be helpful.

 

 

Sent from my iPhone using Tapatalk

 

The one thing about a used DP is you dont really know the mileage and the condition of the catalyst. Also while the COBB is catted its not the same substrate was OEM (material or cell count) the OEM doesnt smell b/c there is a lot of catalyst catalyzing the exhaust gases. Some DPs are better than other, like Max I dont have any smell and I run a GrimmSpeed Catted DP.

 

The more likely culprit is the Y-pipe flanges or a crack in the DP. The stock donut gasket and flange are not the best at sealing even if you buy a new gasket. The best way to tell is to look for an accumulation of soot around the flange. Also the muffler flanges are known to rot out and leak over the years.

 

I know you tightened the turbo nuts and bolts but are you sure you got the one underneath all the way ? Do not wrap the DP, it might seem like the right thing to do, it is not. :)

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