Catted Downpipe Smell?

[B58_ hwAyaq]

I’ve obviously had OEM cats in my cars, and I’ve had a catless car, as well. This is my first time with a “high flow” catted downpipe, and it still has some smell to it. More than I thought I’d get from a catted downpipe.

Just wondering if this is normal.

It is a CG Precision DS-1, so it’s a 200 cell cat.

I figured that this may be smellier than a 400 cell cat like the AA downpipe, but I guess I’m just trying to understand what the “norm” is in terms of smell for aftermarket high flow catted downpipes.

(I’m tuned - not worried about CELs. Just trying to learn so that I know what to expect for catted downpipe purchases in the future.)

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[Souriall91]

I had some smell from my previous catted DP. I’d say it’s pretty normal. I had single cats on my Audi as well and it still had a smell. I wouldn’t worry too much about it.

 

[B58_ hwAyaq]

I had some smell from my previous catted DP. I’d say it’s pretty normal. I had single cats on my Audi as well and it still had a smell. I wouldn’t worry too much about it.

I appreciate it. That’s helpful. Not really “worried” so much as I am trying to set expectations for myself for the future. It’s fine for the Supra, but if I were to get a new 4-door family car, for example, and mod it, I don’t want exhaust smell as much as possible. Trying to figure out if the smell is due to the 200 (vs 400) cell cat or if this is just the nature of catted downpipes.

 

[HaiFrends]

yea, i have a smell on my 200cel catted dp. my CEL also was on before the tune.

 

[type-964]

I have the AA catted and it definitely smells more than stock while it’s warming up.

 

[Extreme Power House]

It depends on the brand. It will smell more than stock but not nearly as much as catless.

Active Autowerke produces the slightest smell, I don't even notice it, but then again, im used to catless

 

[SD_MK]

@mokleen catted doesn't really change much.

 

[METAL]

Try a GESI catted DP next time. My AMS smells sweet but I am running ethanol too.

 

[MisterEff]

Can confirm. Just installed AA catted DP and my vehicle smells like a 90s car now. Wasn’t expecting that, but love the other results.

 

[type-964]

Can confirm. Just installed AA catted DP and my vehicle smells like a 90s car now. Wasn’t expecting that, but love the other results.

Ja that’s exactly what it smells like to me - a 30yo car. And we both have the GESI cat.

 

[NitroYellowMKV]

I am used to my catless but on all my clients cars the AA I can notice smell, besides cold start maybe.

 

[Awales74]

"My AMS smells sweet but I am running ethanol too. " -- fringe benefit of rolling corn.

 

[ethanc]

Just got an aa dp installed along with my fi exhaust. I’m smelling some faint exhaust smells when stopped at a light for more than 10 seconds with windows up not down, is this normal or should I have the shop check for any leaks? I keep reading that some smell is normal, but only when windows down. Or are people smelling 400 cell dp with windows up as well?

 

[B58_ hwAyaq]

Just got an aa dp installed along with my fi exhaust. I’m smelling some faint exhaust smells when stopped at a light for more than 10 seconds with windows up not down, is this normal or should I have the shop check for any leaks? I keep reading that some smell is normal, but only when windows down. Or are people smelling 400 cell dp with windows up as well?

From my research, even quality high flow cats let some smelly exhaust fumes through.

As far as smelling with the windows up, do you have your a/c sourcing air from the outside?

If so, turn on recirculation, and see if that prevents it.

 

[ethanc]

From my research, even quality high flow cats let some smelly exhaust fumes through.

As far as smelling with the windows up, do you have your a/c sourcing air from the outside?

If so, turn on recirculation, and see if that prevents it.

I do indeed have HVAC set to auto, which prioritizes outside air. Is everyone else with 400 cell aftermarket dp’s running with recirculation? Or don’t have noticeable smell? Or just deal with it lol

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