Gas smell with Downpipes

Kett3333 · 08-21-2018, 04:27 PM

Quick question for all you guys and gals with downpipes.

I've been reading the last couple of days that when you put on aftermarket downpipes you inevitably have a gas smell. Are there any quality downpipes that can prevent this? Or due to the aftermarket downpipes construction, you have to live with this in order to have peace of mind they won't crack like OEM downpipes. Any help you can provide would be much appreciated.

Thanks

4everkidd · 08-21-2018, 04:36 PM

Quote:

Originally Posted by Kett3333

Quick question for all you guys and gals with downpipes.

I've been reading the last couple of days that when you put on aftermarket downpipes you inevitably have a gas smell. Are there any quality downpipes that can prevent this? Or due to the aftermarket downpipes construction, you have to live with this in order to have peace of mind they won't crack like OEM downpipes. Any help you can provide would be much appreciated.

Thanks

Downpipes with a high performance cat' will help reduce the smell.

Unfortunately the smell is unavoidable, but I don't find it an issue unless I'm in my garage or stuck in rush hour when it's 90+.

captaindingy · 08-21-2018, 04:37 PM

Quote:

Originally Posted by Kett3333

Quick question for all you guys and gals with downpipes.

I've been reading the last couple of days that when you put on aftermarket downpipes you inevitably have a gas smell. Are there any quality downpipes that can prevent this? Or due to the aftermarket downpipes construction, you have to live with this in order to have peace of mind they won't crack like OEM downpipes. Any help you can provide would be much appreciated.

Thanks

The smell has nothing to do with the quality of the part. It's solely related to the fact that aftermarket dp's are "catless", meaning they have no catalytic converter. This is a metal substrate in your exhaust system that creates a reaction with gasses that pass through it to make the output cleaner.

If this is what you're currently concerned about, I'd definitely do more reading and look into how catless dp's would effect your emmissions and smog certification. This is usually the bigger problem for those that go this route.

gatorfast · 08-21-2018, 07:31 PM

Honesty I don't really smell anything with my DPs. I def noticed it on my e90 m3 but not the f80.

M4Dutch · 08-22-2018, 05:57 PM

The gas smell in my convertible was pretty bad and very noticable. Because of that reason I changed back to stock dp's and changed to midpipe and muffler. No smell, less rasp and loud enough for my taste.

RoundelM3 · 08-23-2018, 07:32 AM

DPs with "race cats" (reduced density catalysts) are available. They are less restrictive than stock but not as "open" as those with no catalyst.

Mike@N54Tuning.com · 08-23-2018, 10:39 AM

Quote:

Originally Posted by gatorfast

Honesty I don't really smell anything with my DPs. I def noticed it on my e90 m3 but not the f80.

+1

There should be no gas smell with catless. The exhaust will have a touch more odour but I hardly notice anything unless the car is idling and I am doing something in the back close to the exhaust.

Saying that I know some people that are super sensitive to any exhaust smell..

Mike

dtmwerksm3 · 08-23-2018, 10:42 AM

I'm running fully catless there's no gas smell, but sitting still with the windows down and the car at idle I can definitely smell the exhaust but other than that you're all good. Just do it, because race car.

SflBimmer8484 · 08-23-2018, 11:05 AM

Maybe try this stuff http://powerpluslubricants.com/fuel-fragrances.html

John Tanglewood · 08-23-2018, 11:09 AM

Quote:

Originally Posted by gatorfast

Honesty I don't really smell anything with my DPs. I def noticed it on my e90 m3 but not the f80.

Same. Smelled on my supercharged e92, no smell with AA DP on my F80

shay2nak · 08-23-2018, 11:24 AM

Some people are hyper sensitive to odors and will pick it up. I'm one of these people. I can smell things others can't. I'm like a bloodhound.

Fast4d · 08-23-2018, 11:43 AM

my cars were catless from 1992 through 2006. I'm sure I lost quite a few brain cells over that time.

mixing leaded race fuel got me hooked on the sweet smell.

I wonder if running full E85 catless will reduce the 'odor'...

Bahn360Photo · 08-23-2018, 03:14 PM

Quote:

Originally Posted by Fast4d

my cars were catless from 1992 through 2006. I'm sure I lost quite a few brain cells over that time.

mixing leaded race fuel got me hooked on the sweet smell.

I wonder if running full E85 catless will reduce the 'odor'...

This definitely helps

I have been avoiding these because of the smell. I have been in few f80's that stink like crazy, e85 mix really makes a difference

blockdoc · 08-23-2018, 04:58 PM

Quote:

Originally Posted by Bahn360Photo

This definitely helps

I have been avoiding these because of the smell. I have been in few f80's that stink like crazy, e85 mix really makes a difference

Interesting. I have the VRSF catless downpipes in stock exhasur in my M4. Don’t really notice much, if any, increased smell

BigHunk · 08-23-2018, 05:07 PM

Whoever changed your DP made mistake installing(aligning) them properly.

Kett3333 · 08-23-2018, 05:55 PM

Thanks for all the responses. Who am I kidding, I putting DP on the car and would have done so even if I was passing out from the smell.

Lee808 · 08-24-2018, 03:44 AM

On a 1 to 10 scale adding downpipes increased smell by 1 and that's only if I have the car running and exhaust facing in my garage and running for a few minutes. Zero smell in traffic or at lights. Zero. I still have secondary cats if you remove those too the smell may increase a bit more.

cigarsmoker · 08-26-2018, 08:11 AM

^ This. Zero smell for me either with catless DPs, but I have secondary cats as well.

gman_newyork · 09-08-2018, 09:09 PM

Quote:

Originally Posted by Andrew@ActiveAutowerke

Maybe try this stuff http://powerpluslubricants.com/fuel-fragrances.html

I use the grape scent and I only smell it when parking in my garage and outside the car. Other than that I don't notice any smell. Catless Down pipes with stock secondaries.

gman_newyork · 09-11-2018, 06:48 PM

Quote:

Originally Posted by Telesto///Man4

I love the smell =) Its like a morning coffee replacement for me.

cbertels · 09-11-2018, 08:11 PM

Catless DPs here and I never notice a smell. Not even at start up and backing out of the driveway with windows down.

NoMoreAudi · 09-12-2018, 06:51 PM

The smell is very strong and noticeable. Not sure how people running "catless" downpipes wouldn't smell anything. Sounds like they have catless dp's that have catalytic converters lol

08-21-2018, 04:27 PM	#1
Kett3333 Registered 4 Rep 4 Posts Drives: Bmw 330ci zhp, M-Sport 740iL, Join Date: May 2013 Location: California iTrader: (0)	Gas smell with Downpipes Quick question for all you guys and gals with downpipes. I've been reading the last couple of days that when you put on aftermarket downpipes you inevitably have a gas smell. Are there any quality downpipes that can prevent this? Or due to the aftermarket downpipes construction, you have to live with this in order to have peace of mind they won't crack like OEM downpipes. Any help you can provide would be much appreciated. Thanks
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08-21-2018, 07:31 PM	#4
gatorfast Major General 4992 Rep 6,859 Posts Drives: 718 Cayman Join Date: Jan 2008 Location: SoFla iTrader: (4)	Honesty I don't really smell anything with my DPs. I def noticed it on my e90 m3 but not the f80.
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08-22-2018, 05:57 PM	#5
M4Dutch Private First Class 36 Rep 145 Posts Drives: 2019 BMW X5 40i xdrive Join Date: Feb 2018 Location: Huntington Beach, CA iTrader: (1) Garage List 2019 BMW X5 [0.00]	The gas smell in my convertible was pretty bad and very noticable. Because of that reason I changed back to stock dp's and changed to midpipe and muffler. No smell, less rasp and loud enough for my taste. __________________ F84 M4 2015 AA midpipe MPE carbon tips BM3 stage 1
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08-23-2018, 07:32 AM	#6
RoundelM3 Major General 1830 Rep 6,984 Posts Drives: 15 F80 M3, 22 G01 X3 30i Join Date: Apr 2010 Location: Wendell, NC iTrader: (2) Garage List 2022 BMW X3 [9.83] 2015 BMW M3 [6.50]	DPs with "race cats" (reduced density catalysts) are available. They are less restrictive than stock but not as "open" as those with no catalyst. __________________ 2015 F80 ///M3 Sedan 7DCT Tanzanite, 2022 X3 sDrive30i 8AT Brooklyn Grey
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08-23-2018, 10:42 AM	#8
dtmwerksm3 Lieutenant 80 Rep 555 Posts Drives: 15 M4 Mineral White/Shakir Join Date: Oct 2011 Location: San Diego, CA iTrader: (0)	I'm running fully catless there's no gas smell, but sitting still with the windows down and the car at idle I can definitely smell the exhaust but other than that you're all good. Just do it, because race car. __________________ 2015 BMW M4— Mineral White on Sakhir Orange/Black DCT 2012 BMW S1000RR — Racing Red/Alpine White - Sold 2009 BMW M3 Coupe — Alpine White on Fox Red, DCT - Sold 2003 BMW M3 — Carbon Black on Black, 6MT - Sold 1995 BMW M3 Coupe — Cosmos Black on Black - Sold
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08-23-2018, 11:05 AM	#9
SflBimmer8484 Brigadier General 1467 Rep 3,157 Posts Drives: . Join Date: Dec 2011 Location: Florida iTrader: (5)	Maybe try this stuff http://powerpluslubricants.com/fuel-fragrances.html
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08-23-2018, 11:24 AM	#11
shay2nak smoke if ya got 'em 1070 Rep 2,179 Posts Drives: F80 M3/Lotus Exige/500 Abarth Join Date: Feb 2011 Location: Calipornia iTrader: (0)	Some people are hyper sensitive to odors and will pick it up. I'm one of these people. I can smell things others can't. I'm like a bloodhound.
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08-23-2018, 11:43 AM	#12
Fast4d Captain 267 Rep 885 Posts Drives: 325 Join Date: Jan 2012 Location: So cal iTrader: (0)	my cars were catless from 1992 through 2006. I'm sure I lost quite a few brain cells over that time. mixing leaded race fuel got me hooked on the sweet smell. I wonder if running full E85 catless will reduce the 'odor'... __________________ SAFE-GUARD tire/wheel/windshield/paint protection is a FRAUD! do not waste your money!
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08-23-2018, 05:07 PM	#15
BigHunk ///M 270 Rep 385 Posts Drives: X5M , iX , S1000XR Join Date: Jun 2018 Location: Edmonton iTrader: (0)	Whoever changed your DP made mistake installing(aligning) them properly. __________________ not rich enough to buy cheap
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08-23-2018, 05:55 PM	#16
Kett3333 Registered 4 Rep 4 Posts Drives: Bmw 330ci zhp, M-Sport 740iL, Join Date: May 2013 Location: California iTrader: (0)	Thanks for all the responses. Who am I kidding, I putting DP on the car and would have done so even if I was passing out from the smell.
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08-24-2018, 03:44 AM	#17
Lee808 Out in the middle of the sea 231 Rep 471 Posts Drives: 2015 M4 Join Date: Jun 2016 Location: Ewa Beach, Hawaii iTrader: (0)	On a 1 to 10 scale adding downpipes increased smell by 1 and that's only if I have the car running and exhaust facing in my garage and running for a few minutes. Zero smell in traffic or at lights. Zero. I still have secondary cats if you remove those too the smell may increase a bit more.
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08-26-2018, 08:11 AM	#18
cigarsmoker Private First Class 47 Rep 101 Posts Drives: 2015 F82 MG Join Date: Jun 2017 Location: Bristow, VA iTrader: (1)	^ This. Zero smell for me either with catless DPs, but I have secondary cats as well. __________________ BM3 OTS Stage II (Fall / Winter) / Paul Johnson Custom E85 tune (Spring / Summer)
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09-11-2018, 08:11 PM	#21
cbertels Captain 1216 Rep 775 Posts Drives: M3 YMB-SS Join Date: May 2016 Location: Orlando iTrader: (0)	Catless DPs here and I never notice a smell. Not even at start up and backing out of the driveway with windows down.
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09-12-2018, 06:51 PM	#22
NoMoreAudi Lieutenant 222 Rep 421 Posts Drives: F86 Join Date: Sep 2015 Location: California iTrader: (3) Garage List 2019 X6M [0.00]	The smell is very strong and noticeable. Not sure how people running "catless" downpipes wouldn't smell anything. Sounds like they have catless dp's that have catalytic converters lol
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