High Flow Cats smell vs Straight Downpipes without Cats!!

soooma · 04-10-2018, 08:05 PM

Just did APR High Fkow Downpipes and curious to know,
Am I the only one bothered by the SMELL even while cruising at low speeds!!
Granted the car is better overall and throttle is better but the smell!!

Can’t imagine will be worse without cats!!

Any experience ?!

Craze · 04-11-2018, 04:57 AM

I found the smell not to be too bad with catless

Apparently on non turbo cars its worse

Rocketsoda · 04-11-2018, 11:47 AM

Anyone know what the smell is like for gutted downpipes? Would the double wall help?

Used2be · 04-11-2018, 12:02 PM

Quote:

Originally Posted by Rocketsoda

Anyone know what the smell is like for gutted downpipes? Would the double wall help?

I'm sure the stock double walled DPs will smell the same without the cats as the aftermarket catless DPs. I have the gutted stock DPs and there is a definite smell for me when I come to a stop and roll down my driver's side window. That is the only time it's objectionable for me though. If I'm moving at anything above 5 mph I don't notice a smell with the window down. No smell at any time through an open sunroof, stopped or moving.

soooma · 04-11-2018, 12:05 PM

Quote:

Originally Posted by Used2be

I'm sure the stock double walled DPs will smell the same without the cats as the aftermarket catless DPs. I have the gutted stock DPs and there is a definite smell for me when I come to a stop and roll down my driver's side window. That is the only time it's objectionable for me though. If I'm moving at anything above 5 mph I don't notice a smell with the window down. No smell at any time through an open sunroof, stopped or moving.

My issues is and I am the OP

I have smell with HFCats!!!

Vic55 · 04-11-2018, 12:25 PM

Maybe you need to join the audi boards--- since you are talking about an S8 and asking for technical help.

soooma · 04-11-2018, 02:07 PM

Quote:

Originally Posted by Vic55

Maybe you need to join the audi boards--- since you are talking about an S8 and asking for technical help.

I am an Audizine member and I will do that,
But feel that people here seem knowledgeable about all these issues being owners of many brands like yourself Vic55

But sure
I will pose same question at that forum too!

04-10-2018, 08:05 PM	#1
soooma ///MD 1442 Rep 3,999 Posts Drives: M5 F90 Join Date: Apr 2013 Location: NC iTrader: (1)	High Flow Cats smell vs Straight Downpipes without Cats!! Just did APR High Fkow Downpipes and curious to know, Am I the only one bothered by the SMELL even while cruising at low speeds!! Granted the car is better overall and throttle is better but the smell!! Can’t imagine will be worse without cats!! Any experience ?! __________________ Life is too short even if you live to be a 100!! As what really counts is the few moments we are really happy and excited! -Kids, Family, Success, Career, Helping others stand on their feet (Paying back and sometimes forward), Travel, Seeking the truth, Reading, Hobbies eg ///Madness -
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04-11-2018, 04:57 AM	#2
Craze Captain 170 Rep 686 Posts Drives: M5 E60, M5 F10, X5 50i Join Date: Oct 2017 Location: Australia iTrader: (0)	I found the smell not to be too bad with catless Apparently on non turbo cars its worse
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04-11-2018, 11:47 AM	#3
Rocketsoda '13 M5 18 Rep 35 Posts Drives: 2013 BMW M5 Join Date: Mar 2015 Location: Montreal, Quebec, Canada iTrader: (0)	Anyone know what the smell is like for gutted downpipes? Would the double wall help?
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04-11-2018, 12:25 PM	#6
Vic55 Lieutenant General 26317 Rep 11,759 Posts Drives: 2024 BMW M3 CS-2025 Audi RS6P Join Date: Jul 2009 Location: THE Orange County iTrader: (9)	Maybe you need to join the audi boards--- since you are talking about an S8 and asking for technical help. __________________ 2025 Audi RS6 Performance 2024 BMW M3 CS Frozen Solid White 2024 Mercedes Benz AMG GT63 2022 Porsche Carrera GTS Coupe Shark Blue 2012 Mercedes Benz C63 AMG Black Series Obsidian Black
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