Ridin Dirty

Here's a question to which I likely know the answer but forum's been a lil sleepy lately so I'll throw this out there......

Sooooo I thought removing my cats would be a nice touch and installing a Fab by-pass. And it is a good idea very pleased with results and sound. Running Fisters too. Lil loud but I like it like that, no drone, so all is well...EXCEPT....
IT FREAKIN STINKS!!

No one ever talks about the noxious aspect of this minor performance modification....does that make mechanical sense to you all? I mean I have to warm the car up outside now or the smell permeates through the house and I get hell from the wife. This smell should be discussed as a tangible implication for those considering removing their cats. Driving on a beautiful sunny day, got your sunroof open? Stop at traffic signal.....yup smell it.

Allow me to provide an analogy:
Now our cars are not exactly the most green things rolling around but as a comparison with cats in place on the 993TT on scale of 1 to 10 was about a 3/10 with noxious fumes.....Using my Cayenne turbo as the control vehicle in this experiment; it is at level of <1/10 on the stinkometer. Now with the cats off the 993 its like 8/10. That bad!! (Note 10/10 would be maybe a tri-axle dump truck in your garage.)
....... So, 8/10 stink???

But again reason for post...is that about right? Should it smell "that" bad???.....or is something else at play here? But I don't recall a night and day difference it kind of crept up. And my Protosport/Protomotive ECU knows it doesn't have cats. so....no freaked out O2 sensor, no codes thrown. Note: I think my idle has been a bit rough lately and my exhaust visual puffs of steam at warmup had always been even now I've noticed I have more out of the passenger tailpipe. Donno if that means anything; just different.


Disclaimers: I know, I know, get race cats (...nah), or pollution implications? well I drive the car 1000k/year so im not raising sea levels; further, no animals were harmed in this post (unless they were in the garage).

Thanks all!

Quadcammer

this is something of a no brainer, no?

When the car is cold, it will run rich. without cats, you get a crap load of raw fuel right out the exhaust pipe. If you feel you have a rough idle, go through the usual suspects of ignition and fueling.

I ran without cats on my supercharged mustang for years. I got tired of the smell and the headache inducing fumes. I went with sport cats on the 993TT and would never delete cats again.

Mike J

What is the smell like? Sulfur? Fuel? Burning oil?

I like my clean air, so I run with the cats all the time - for the perhaps performance increase over sport cats, its just not worth the side effects, like the smells you are talking about.

Cheers,

Mike

sonny1

You will need a reflash to take care of that particular cold cycle.,cheers,
Sonny1.

ronnie993tt

Thanks for post. Never heard of this. Might keep micky population down!

PiB993

Is your car belching flames though now?

sonny1

You can call Garrett Lim,at GIAC, regarding a possible re-flashing and besides a bit of more hp never hurts!Sonny1.

owen meany

I am a strong supporter of the idea that we all need to be running cats. It stinks because that crap is bad for you, your wife, the neighbors kids and the rest.
Sounds cool to run with no cats, but come on guys, we're being piggy enough running at 10 mpg.
We (Porsche owners) have a bad enough rap as it is, imagine if the general public started to learn that we are polluting the air like it was 1970 just so that we got a few more horses and some more noise?
Not good PR that's for sure.
I'm sure I'm not in the majority. But since you asked, that's my worthless 2 cents.
Thanks

DM993tt

you normally warm up the car inside the house?

chsu74

My wife complains that I smell like I have been riding a motorcycle when I take the TT out. I have to back into my garage because it is easier to maneuver around the driveway.

Ridin Dirty

Well....actually...I think I specifically didn't ask for the "cat-ethics" opinion. I just wanted to know if anyone's rear end stinks.

Sigh...gotta defend myself I guess. Since I never want to be accused of ignorance (which is why I had the disclaimer) and running my 993 for....lets see 874 miles last year is not as I said "raising sea levels". In fact, in PA they don't even do emissions for vehicles driven less than 5000k miles.
And by socially responsible accepted definitions I suppose my Cayenne Turbo at 12mpg 20k/ year is alright then? How bout the dozen or so Suburbans in my hood commuting to work...alone...everyday? ...and lumbering I might add.

Further, I run a small fleet of hybrid delivery vehicles in my business. My choice, and no the gov subsidies did not cover my net expenses for them. My overall "print" is far less than most.
The real "green" differences are being made by the half million miles my "green" vehicles are driven every year in commerce. That's the real change. Business is the backbone of north America and it must transpire for us remain relevant but in conducting said business we can be environmentally responsible. And my business is a leader in that regard.
We as Porsche drivers have a bad "rap"? I was blissfully unaware of this. Why do we drive them then? I was of the opinion that the majority of Renn are at the upper end of conscious members of society actually paying the bulk of our nation's taxes which fund all these green programs, policies, and subsidies in the first place.

off on tangent there....but I didn't start that...and to reiterate, I actually called for not "going there".

Anywho.. back to original question:
Car did not smell like that with the cats removed initially..it took awhile. Which is the reason for the post. Something is up. And i hate to cart her 300 miles back to Proto.
Thought there was something overt I was missing in repair or to find another "cat-less" fellow out there telling me "yup it's gonna stink like that". In which case I would invest in some 100 cells b/c it is indeed unacceptably pungent and makes a less than desirable experience which would in turn actually potentially preclude others from choosing this route.

And yes I warm up in garage with garage door open of course, but it permeates, so I must pull it entirely outside and close g-door behind it.

And no, ha!, no flames ever observed out of tailpipes. And the smell is exhaust gas..gas, not sulfur, not oil.

Thanks again.

Joe

owen meany

Shhzaammm,
It truly sounds like you're making loads of wonderful decisions. We all thank you for those. I didn't mean to call you out directly. I stand behind my believes. It just sounds like your safe from my attack.
Best regards.
Oh about the Porsche guy thing. As soon as I got my first Porsche, nearly everyone I knew said "I didn't think you were a Porsche weenie". I think people see an old Porsche and they think it's the same as a finance guy driving a brand new one. You can hear the Top Gear guys talkin' SHI+ about Porsche guys too. I don't agree of course : )

PiB993

A little race fuel has a nice sweet smell.

It seems like the British blokes get a pass on cats all the time. They produced cars cat-less much later than in the USA and AFAIK have had them legally removed as well in some cases.

And as far as the Porsche guy thing - somebody parked a later model P-car in our garage over night in a non-parking space and of course by default the French lady next door blames me even though I have no idea who's it was.

My trunk/bonnet flap hole smells of fuel a bit. I need to check the fuel hose bands in there.

Seems like the OP should check for some kind exhaust leak. For your own health while you are driving!

geolab

here is the Porsche explanation:

http://www.pcarworkshop.com/images/7...996_620496.pdf

Quadcammer

i think his problem with raw fuel smell, not the rotten egg from the cats smell.