Catted Downpipe Smell?

[MoTeC_R]

Perfect, that’s what I wanted to know. I’m taking it to a different bmw shop today to have it checked for any leaks along the exhaust or dp/turbo. I brought up the smell issue to the original install shop and they said they just needed to tighten down the v band a bit more. But smell is def still very prominent with recirc off, so def a leak somewhere. Hoping it can get identified and fixed today!

Did it help?

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[ethanc]

Did it help?

Unfortunately not really. They did find an exhaust leak in the dp to mid pipe connection, and they reduced it (still a small leak they said from the smoke test) but should be a lot better. Still smelling fumes through the vents when coming to a stop with HVAC recirc off, or even with recirc on if decelerating in sport mode with downshifts and loud pops. I’m still scratching my head as to whether this is just the nature of high flow catted downpipes, where some smell is inevitable when driving primarily in Sport mode, or if there is a leak in the engine bay where dp meets turbo. They checked it and said the v band seemed to be on there good, so not sure where it could be leaking, maybe still from that midpipe to downpipe connection? But would that give such a strong smell?

Debating whether to just go back to oem downpipe at this point to get over all of this headache

 

[swrdply400mrelay]

Just got the AA catted dp installed. I noticed a smell like gas coming from the engine bay. When I stand behind the exhaust tips there’s not a smell.

Is this normal or a leak?

 

[ethanc]

Just got the AA catted dp installed. I noticed a smell like gas coming from the engine bay. When I stand behind the exhaust tips there’s not a smell.

Is this normal or a leak?

Yeah I was just noticing that today as well, with engine running, or soon after turning off the engine and I sniff sort of near the passenger side cowl where the hood meets the passenger windshield, it smells like exhaust/gas. That’s where the HVAC intake is so makes sense that it gets sucked in.
Do you smell anything when you come to a stop and have HVAC running with recirculation off (A mode)?

 

[swrdply400mrelay]

Yeah I was just noticing that today as well, with engine running, or soon after turning off the engine and I sniff sort of near the passenger side cowl where the hood meets the passenger windshield, it smells like exhaust/gas. That’s where the HVAC intake is so makes sense that it gets sucked in.
Do you smell anything when you come to a stop and have HVAC running with recirculation off (A mode)?

Haven’t tried yet, usually windows are closed and HVAC is off. I’ll give it a try tomorrow. I opened the hood and the smell is pretty strong underneath.

 

[ethanc]

Haven’t tried yet, usually windows are closed and HVAC is off. I’ll give it a try tomorrow. I opened the hood and the smell is pretty strong underneath.

Yeah give that a try and see. Try it with HVAC recirculation off (A mode), this should give smell in cabin if what you're experiencing is the same as me. Recirculation on helps mostly, but when decelerating in Sport with loud pops on downshifts, and then coming to a stop, even recirculation on I can smell a little inside cabin

 

[swrdply400mrelay]

Yeah give that a try and see. Try it with HVAC recirculation off (A mode), this should give smell in cabin if what you're experiencing is the same as me. Recirculation on helps mostly, but when decelerating in Sport with loud pops on downshifts, and then coming to a stop, even recirculation on I can smell a little inside cabin

Yea so I put it in A and could smell it at a stop. I asked the shop that installed, and said it's normal, and worse with catless, so I'll probably leave it in M mode most times.

 

[ethanc]

Yea so I put it in A and could smell it at a stop. I asked the shop that installed, and said it's normal, and worse with catless, so I'll probably leave it in M mode most times.

Hmm yeah I’m just not entirely sure if that’s the proper behavior or not. Everyone else keeps saying no smell in cabin, can smell only outside behind car. But for you and me, we can easily and quickly smell it with HVAC set to A

 

[swrdply400mrelay]

Hmm yeah I’m just not entirely sure if that’s the proper behavior or not. Everyone else keeps saying no smell in cabin, can smell only outside behind car. But for you and me, we can easily and quickly smell it with HVAC set to A

I asked my friend who also got the AA cat version of the dp, he said pretty much the same thing, he can smell it only with windows open at a stop, but he's not sure what HVAC mode he has it on so he's going to check

 

[Eastwood]

From my experience, every car I've had a downpipe installed on there's always an initial smell, usually a chemical smell that lasts for a short time. It usually dissipates same day, but it's the smell of manufacturing oils, grease and oil from hands burning off.

Personally I have 0 smells from my downpipe at this time but it did when first installed. Only in cabin smell comes from me eating spicy food.

 

[ethanc]

From my experience, every car I've had a downpipe installed on there's always an initial smell, usually a chemical smell that lasts for a short time. It usually dissipates same day, but it's the smell of manufacturing oils, grease and oil from hands burning off.

Personally I have 0 smells from my downpipe at this time but it did when first installed. Only in cabin smell comes from me eating spicy food.

Yeah makes sense for the initial few days for sure. But I’m at almost 400 miles on it now.. and it’s definitely exhaust smell and not new component smell. It must still be from a leak then I guess? At this point, I’m just wondering how many people are driving around with exhaust leaks with aftermarket dp, as it seems like it’s so hard to get a proper install and/or trace any leaks (mine was installed at a reputable bmw performance shop in Raleigh NC, and then I went to another bmw shop for a second opinion) ?

 

[STV3]

I can't recall if it was already mentioned in this thread but did you make sure the gasket was installed in between the DP and turbo housing?? A lot of people miss it because it sits inside the DP flange.

 

[ethanc]

I can't recall if it was already mentioned in this thread but did you make sure the gasket was installed in between the DP and turbo housing?? A lot of people miss it because it sits inside the DP flange.

Didn’t explicitly confirm with shop but I did see that the gasket was preinstalled on the dp, with a zip tie around the front o2 bung to effectively prevent the gasket from separating during shipping. So I’m assuming gasket was used, I also see the original gasket still on my oem dp. I did go ahead and order a new oem gasket and v band, in case I want to have it reinstalled again

 

[STV3]

Didn’t explicitly confirm with shop but I did see that the gasket was preinstalled on the dp, with a zip tie around the front o2 bung to effectively prevent the gasket from separating during shipping. So I’m assuming gasket was used, I also see the original gasket still on my oem dp. I did go ahead and order a new oem gasket and v band, in case I want to have it reinstalled again

Yeah doesn't hurt to check. They could have snipped the zip tie before installing it and simply placed the DP down to roughly and it could have popped out.

 

[ethanc]

Yeah doesn't hurt to check. They could have snipped the zip tie before installing it and simply placed the DP down to roughly and it could have popped out.

Yeah I think I plan on having everything redone anyways with new gasket and v band, with a different shop this time, and explicitly tell them to ensure gasket is in place and be cognisant of dp to turbo seal. While checking for exhaust leaks, the second shop saw that my transmission pan/bolt is leaking/moist. So will need to swap back to oem dp, take it in for warranty (with how stingy Toyota has been with warranty on gr’s) and put back the AA with all new hardware

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