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Old Sep 14, 2005 | 05:39 PM
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Default !cats and gas smell

From reading a few threads about deleting cats, it seems one of the bigger complaints is the smell (unburned gasoline)
Right now I'm considering headers and true duals (over the axle) but since my youngest boy (3 months old) likes to ride in the bird, I don't really want to choke the kid on gas fumes, so is it possible to tune out the gas smell, or would it be better to get a set of hi flow cats
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Old Sep 14, 2005 | 06:11 PM
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you are probably better off gettin some high flow cats, the smell is really strong at certain times to. keep the kid safe
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Old Sep 14, 2005 | 06:23 PM
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The smell of the exhaust is definetly different without cats...but it doesnt smell like gas. To me smells like motorcycle exhaust.
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Old Sep 14, 2005 | 07:01 PM
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Mine only smells on startup. It doesn't smell like gas either.
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Old Sep 14, 2005 | 07:35 PM
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currently with just open headers, the fumes aren't that noticeable, i guess if you were idling at one spot it would be bad, but even with the headers exiting right under my feet i never realized the smell enough for it to be a problem, although i do smell it from time to time, its worse standing around the car than being in the car atleast for my case.
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Old Sep 14, 2005 | 07:43 PM
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When I used to run an ORY with my setup the smell was worst when starting the car up in the garage or pulling back into it after driving. The smell would seem to fill the gargage and once you exited the car it would stick to you like glue. I DD my SS alot and being in work clothes smelling like unburnt hydrocarbons is not too cool. I added a Catted Y and don't have to worry about it no more.
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Old Sep 14, 2005 | 08:35 PM
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I don't notice it, even with the cutout open.
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Old Sep 14, 2005 | 08:43 PM
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I have a 2001 Trans Am, which I added Pacesetter headers and no cats w/ hooker cat back exhaust... and I'd have to say the exhaust smells better w/out cats than with, no more sulfer... but I guess it is all personal preference. I did not notice that big of a change. I had been worned by people that I wouldn't be able to stand the smell w/out cats, but I would say they were wrong.
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Old Sep 14, 2005 | 08:47 PM
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Originally Posted by tjswanson2001
I had been worned by people that I wouldn't be able to stand the smell w/out cats, but I would say they were wrong.
That's what I heard (read) that the smell was almost unbearable, but you guys seem to think it's not so bad, now I myself don't mind the smell of gas, but the little kid might, so I may just toss on a set of cats just to be safe, at least until he gets older, not gonna look good to drop a kid off at daycare smelling like the pits @ Daytona
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Old Sep 14, 2005 | 08:58 PM
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I have the exhaust in my sig, dumped. and let me tell you when i drive with my windows up theres days i smeel fumes faintly then theres days that its incredibly strong. me i like the smell but for your kid i would say stay away from that and add some high flow cats. theres times where i come home n when i walk into my house i have a smell of exhaust and even my parents say i smell like i was under the car while it was on.
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Old Sep 14, 2005 | 09:18 PM
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I love the smell of a V8 with no cats.
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Old Sep 14, 2005 | 10:43 PM
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Originally Posted by Ryan02SS
When I used to run an ORY with my setup the smell was worst when starting the car up in the garage or pulling back into it after driving. The smell would seem to fill the gargage and once you exited the car it would stick to you like glue.
It is the same for me...if I'm in the garage after the car has been run, my clothes pick up the smell...it's not actually a gasoline smell...the description of motorcycle exhaust is pretty accurate. Anyway, it's annoying...IMO.
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Old Sep 14, 2005 | 10:52 PM
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I would also agree that you should put High Flow Cats intead of ORY. My wife is really sensitive to chemicals, If I start the car in the garage I usually ask her to come out the front door and I back up the car. Otherwise she will get light headed. Usually it is stronger on start up but sometime you can smell it from the inside when the you are sitting at a light with the windows down. I wouldn't get your kid hooked on 93 octane gas smells this early .
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Old Sep 15, 2005 | 04:04 PM
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My car reeks of unburnt fuel at start up, and when sitting in traffic stopped. Smells like i've got a cup of 93 octane premium gasoline sittin in the backseat.

and my car is tuned... to the right a/f's
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Old Sep 15, 2005 | 06:58 PM
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running a little rich are we?
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Old Sep 15, 2005 | 07:38 PM
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Originally Posted by 85transamtpi
running a little rich are we?
Not according to the wideband on the dyno's I've been on. Dunno if my a/f is just wacky and the tune didn't really work for idle or what.
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Old Sep 15, 2005 | 07:48 PM
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I also stink if outside the car after starting it in the garage. I dont smell it at stoplights and im dumped at the axle with tds. I think if you go over the axle and out the back and are tuned correctly you should not smell it. And whatever you do, shut the vents and stay in the car until outside the garage.
Ultimate safety would be the hf cats though. Startup is the worst.
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Old Sep 15, 2005 | 08:12 PM
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Forgot to add that the more overlap your cam has the worse the smell will be..... TR230 sums that up.
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Old Sep 15, 2005 | 09:13 PM
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It's not gas that smells.

You need to to understand what cats do:

1) They get red-hot
2) Fumes from the exhaust valves get throught the headers, and into the red-hot cats, which burn off what didn't get burned in the cylinders, and that includes, hydrocarbons, and some traces of Nitrogen/Sulfur containing compounds. (hence the smell if that doesn't get burned)

3) When cats are cold during initial startup EGR kicks in (EGR= Exhaust gas recurculation) What it means is that when cats are cold, they are inefficient (dont' burn the hydrocarbons as well) and fumes get re-circulated. cold-cats are bad, hence removing them further away from their orginal location is illegal. Even if you have catted Y-pipe on midlenght or long-tube headers it's still illegal. (because they are not as close to the block, and won't heat up as much)


4) Personaly I think cats are good. They don't rob as much power as some idiots claim. 1-3 rwhp max. 3 rwhp is nothing, and you don't smell like freaking rotten eggs.
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Old Sep 16, 2005 | 05:29 AM
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Originally Posted by 2K2WS6TA
From reading a few threads about deleting cats, it seems one of the bigger complaints is the smell (unburned gasoline)
Right now I'm considering headers and true duals (over the axle) but since my youngest boy (3 months old) likes to ride in the bird, I don't really want to choke the kid on gas fumes, so is it possible to tune out the gas smell, or would it be better to get a set of hi flow cats
where does this info come from???????????????????????????

Seriously.

You guys may have had cats since the 70's but in the UK it wasn't mandatory until 1994.

I've never smelt any petrol fumes because of not having them. I currently own 3 petrol cars all without cats as standard. No problem.


with any exhaust that exits under the car you will be under more risk of fumes getting to the interior (cats or no cats). This is why in most places such exhaust systems are illegal.

Just get the exhust exiting as per normal = no worries.


BTW an adult would fair no better to consentrated levels of fumes than a child in all reality. If you think its bad enough to affect them then its certainly enough to give the driver a light head and probably cause an accident.


If you can smell petrol (unburnt?????) then you have other far more serious problems with your car.
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