Cabin smell going catless DP

[XLeezardx]

I found the problem by opening on the hood with the engine on. Took a wiff and noticed the potent smell of exhaust gasses. Then I let the engine completly cool down, then put my car on jacks. Removed the undergaurd and heatsehield. I then turned the engine on and felt my hand around all connections points and sure enough I felt the gush of air. Replaced the Copper gasket with OEM, problem solved. Now dont blame crucial for this cause this could be just my bad lucky.

 

Edit: "Luck" hooked on phonics didnt work for me. =P

[tommypenguin]

I found the problem by opening on the hood with the engine on. Took a wiff and noticed the potent smell of exhaust gasses. Then I let the engine completly cool down, then put my car on jacks. Removed the undergaurd and heatsehield. I then turned the engine on and felt my hand around all connections points and sure enough I felt the gush of air. Replaced the Copper gasket with OEM, problem solved. Now dont blame crucial for this cause this could be just my bad lucky.

 

Ya figured I would get a big whiff if it had been from one of the 3 gaskets i messed with under the hood. Since I can,t but if I put my head under the car take a whiff by the driver's door, it wreaks of exhaust. I didn't mean to talk bad about crucial, hear they are amongst the best in aftermarket parts for us but i've read many threads while searching exhaust leak smell about the crucial gaskets failing/disintegrating. I have a bpm flex up pipe and with brand new oem gaskets, I wasn't too worried about that leaking. Though I should have been with as many people having leaks.

[XLeezardx]

Ya figured I would get a big whiff if it had been from one of the 3 gaskets i messed with under the hood. Since I can,t but if I put my head under the car take a whiff by the driver's door, it wreaks of exhaust. I didn't mean to talk bad about crucial, hear they are amongst the best in aftermarket parts for us but i've read many threads while searching exhaust leak smell about the crucial gaskets failing/disintegrating. I have a bpm flex up pipe and with brand new oem gaskets, I wasn't too worried about that leaking. Though I should have been with as many people having leaks.

 

Ok im home now, sorry if I sounded like an ass I was in a big hurry lol. I think copper gaskets seal very well, but they seem to be really weak and crack overtime due to high temps. Plus they are expensive! I would just get OEM gaskets and bolt eveything up properly.

 

I would go under the car and check for loose bolts. After a few days of stage 2, I was missing 3 nuts off the DP studs. Thats right, they were gone . I purchased some lock nuts and applied high temp locktite on them. Never had a problem since.

[SeeeeeYa]

"heavy torque" Those torque specs exist for a reason the heat expansion will cause the over torqued bolts to break or damage the pipes. Factory torque specs, factory gaskets and no magic spray works. If it doesn't then there is something is wrong and you should figure either figure it out or weld the joint

 

With all due respect, I have been wrenching for over forty years and have yet to have a reason to question my methods. Perhaps it is the interpretation of "heavy torque" that is the issue here. But to those of us who have a relationship with mechanics, and know through experience what we are doing instead of depending on some, sometimes erroneous, abstract paper to guide us 'heavy torque' is an obvious comment. It doesn't mean break it. It means torque to the limits of the circumstance at hand. Thus far I have never broken a bolt or had a leak. In the years of building successful race motors with which I broke several national records I never suffered a failure of any kind. To me, advising 'heavy torque' on exhausts with the caveat to use a torque wrench on torque sensitive applications should be issueless.

 

Frankly, after years following these forums and reading about endless leaks from up pipes, down pipes, and exhausts from people following the 'torque specs' I think it is time someone posted information of value. If the person wielding the wrench cannot destinguish between enough torque to snap a bolt and torque heavy enough to secure it properly they should pass the wrench to someone who can. I can.

 

My comments are intended to help, based on successful experience. If it is your intention to get into the finer points of building or modding motors, or cars, do so. If your intention is to belittle, beware of your opponent.

[rao]

With all due respect, I have been wrenching for over forty years and have yet to have a reason to question my methods. Perhaps it is the interpretation of "heavy torque" that is the issue here. But to those of us who have a relationship with mechanics, and know through experience what we are doing instead of depending on some, sometimes erroneous, abstract paper to guide us 'heavy torque' is an obvious comment. It doesn't mean break it. It means torque to the limits of the circumstance at hand. Thus far I have never broken a bolt or had a leak. In the years of building successful race motors with which I broke several national records I never suffered a failure of any kind. To me, advising 'heavy torque' on exhausts with the caveat to use a torque wrench on torque sensitive applications should be issueless.

 

Frankly, after years following these forums and reading about endless leaks from up pipes, down pipes, and exhausts from people following the 'torque specs' I think it is time someone posted information of value. If the person wielding the wrench cannot destinguish between enough torque to snap a bolt and torque heavy enough to secure it properly they should pass the wrench to someone who can. I can.

 

My comments are intended to help, based on successful experience. If it is your intention to get into the finer points of building or modding motors, or cars, do so. If your intention is to belittle, beware of your opponent.

 

 

I am very afraid

 

I speak from personal experience. I did the UP, DP swap on my car almost three years ago and have not had a leak; I have helped several others do the same job and not one person who used factory gaskets and factory torque specs has had ANY leak whatsoever. If you want to use another method please feel free. Anybody who wants to use copper gaskets go ahead and knock yourself out. The FACT is that sealer and large torque is not necessary, they are a band aid, not a solution.

[tommypenguin]

Oh brother.... well regardless I thank you both for chiming in and giving me your opinion. I respect both of you guys, definitely seen a lot of your posts. I wasn't trying to stir any thing up.... just wanted to get some advice from guys who have more experience than I with the car, which I did and am about to try and diagnose my leak.

 

I will let you know what the result is, ironically, when I drove home from work, I didn't smell any exhaust, the only time I noticed it was last night, and it was cold for the first time in a while. It gave me a headache drawing my immediate concern. I will post when I learn more.

[tommypenguin]

To test your work you can use an old trick, find a piece of small plastic plumbing pipe long enough to reach whatever joint you question, then with the pipe near the suspect interface sniff away . The same pipe will let you listen similarly to specific areas.

 

Yup once again, you were right, I used a hollow hockey stick, with no stick blade on it, had a buddy give the car some gas, once again I couldn't smell it under the hood, but when I put the hockey stick end by the dp>mp connection and took a whiff and voila exhaust smell, I should have gotten a pic. My buddy said I looked like crack head, sniffing a line with a 10 foot pole:lol:. Thanks a lot guys, I need to get a gasket and sealer and go to town on it, won't be able to make time till probably friday, got hockey again tonight and tomorrow.

[XLeezardx]

I had my little brother rev the engine. =) but good idea seeeee ya!

[rao]

Group hug via PM .

 

I am glad you folks are getting your problems sorted out.

[tommypenguin]

Once again order is restored.

[psucaptainkickass]

Just throwing this in here. Crucial gaskets suck.

[tommypenguin]

Just throwing this in here. Crucial gaskets suck.

 

That is typically what i've read from the posts i looked up that had exhaust leaks after going stage 2.

[tommypenguin]

Ok then, please excuse me for my stupid questions. Delete or lock this thread please. Thank you

 

Lee

 

 

I'm glad this didn't happen.

[darb1]

I used to smell it in my 02 WRX, not with my LGT though. MR DP and SPT CB.

[tommypenguin]

Next time open your trunk and take a sniff . Back when I was catless (gutted stock components, Cobb DP w/HFC now!) the catless smell was very bothersome. I traced it to the invisible vent flaps inside both rear sides of the trunk. The exhaust was entering there and migrating into the cabin. Cracking the front windows exacerbated things, apparently creating a vacuum which sucked air from those vent flaps out the window. Cracking the back windows, however, relieved the smell.

 

My concern was this, if I could smell the exhaust then how much of it was carbon monoxide. I actually rode with the CO monitor from home but it never indicated any present. Still, it makes one wonder.....

 

Alright So on friday, I checked my car for leaks on every connection, everything was still tight. I went to my buddies place, put the car up on jack stands and he gave it gas while I put my hand around every exhaust connection, could not feel any air hissing out, like there would be if I had an exhaust leak, no smell from the engine, no smell from the mid pipe to dp connection.

 

I stuck my head in the trunk today after my ride to work, it smelled of exhaust hard. Could you be more specific about the "invisible" vent flaps, were you able to use anything seal it?

[SeeeeeYa]

Alright So on friday, I checked my car for leaks on every connection, everything was still tight. I went to my buddies place, put the car up on jack stands and he gave it gas while I put my hand around every exhaust connection, could not feel any air hissing out, like there would be if I had an exhaust leak, no smell from the engine, no smell from the mid pipe to dp connection.

 

I stuck my head in the trunk today after my ride to work, it smelled of exhaust hard. Could you be more specific about the "invisible" vent flaps, were you able to use anything seal it?

 

Actually, you can't really seal it (them) without interferring with the car's ventillation system, which really complicates this issue.

 

These vents are a series of simple flaps that act as (inefficient, obviously) valves that are supposed to let air out of the car without letting anything in. Joke on us. All or most cars have them. They are 'invisible' because they are out of sight from the inside of the trunk, covered thin deep wells in the rearmost outside corners of the trunk. And on the outside they are overed by the plastic 'bumper' cover. If you ever see a car with its rear bumper off they are obvious.

 

Although I don't have the smell anymore since installing my catted Cobb DP I still say "where there is smoke there is fire," meaning that there must be a carbon monoxide component coming into the car! As long as you can smell exhaust due to having it revealed by catless pipes how could CO not be present??!

 

Because I am now aware of this I do not cruise anymore with the front windows cracked, something that bothers me because I have always liked them open somewhat.

 

I posted more about this some time ago. People mostly ignore what they cannot see, or sense. However, people die everyday because they fall asleep at the wheel. Some, I am certain in my own mind, die as a result of carbon monoxide filtering in via these vents and at least adding to bordom and normal sleepiness if not putting people to deadly sleep all on its own.

 

These are terrible claims, I know. However, on more than one occasion I have forgotten and driven for, say, half an hour with my front windows cracked on a beautiful cool day and for no good reason found myself oddly loosing my mental crispness. As soon as I close the windows, clear the cabin with the ventillation fan, breathe deeply and perhaps have a sip of water my head clears.

 

These flaps are crude things, never meant to deal with deadly exhaust gasses. In fact they are often messed up. Opening doors sucks them in and slamming a door pushes them out, sometimes they get stuck and don't 'flap' anymore. Go to a repair shop somewhere and you'll see what I mean.

 

I can hear people say it now, "I call BS! The government is watching out for us and they wouldn't allow a potential deadly mechanism like this!" I'll bet those same people are also unaware of how many people die each year from carbon monoxide poisoning sitting on the transome of boats, from space heaters, and so on. And I agree that it is almost incomprehensible that I could be correct here. But smelling is believing to me. And until someone can explain how exhaust smells can be so strong and NOT contain carbon monoxide I will continue to believe a silent killer has been engineered into about all modern cars.

[tommypenguin]

I've been debating about whether I should go to a catted dp over this. What kind of pipe were you running before you went to a cobb? Since I have a perrin catless dp, I was thinking about going with a perrin catted dp to ensure it would mate up to my perrin catback. I normally can smell this exhaust most when I'm in boost, typically on the highway, which could be from running rich with my cobb stage 2 base map. Would protuning help resolve the issue.... or do i need the cats to get rid of the smell? Definitely a bit of a concerning issue, it makes me not want to take long drives with my car, most of the time i can't smell a thing, but when I can... yikes. I need a for sure fix, I wonder how many people are running cats with a 3" dp and still have no smell issues.

 

There has to be a substantial amout of co2 in the cabin, i know what you mean about it making you a bit slower. I didn't think there was a way to seal the bumper vents, and I'm not sure if it would be a good idea to seal them if it were possible, just because of how the ventialtion is supposed to work. I found a thread you posted a year ago, talking about your suspicions with the vents and other people having the issues, but I didn't find really anything conclusive as a fix. Thanks for helping me out Seeee Ya...

[SeeeeeYa]

Since installing the Cobb DP w/HFC there have been zero smell issues. Before that I was running all decatted stock pipes. It was with those that the issue was revealed.

 

Regardless of whether you can smell the exhaust or not the carbon monoxide will remain, assuming as I do that it is there. Why wouldn't it be, cats don't remove carbon monoxide. Therefore whether you go with a high flow performance cat or not remain aware of the issue and you should be ok.

 

By 'illegally' running catless I became aware of something that has bothered me for many years. Only on long drives, during which I had my front windows partially opened for ventillation and communication with the outside, especially in the mountains, I would sometimes become terribly and inexplicably sleepy. Nothing except stopping and getting out for a while helped. It wasn't lack of sleep. I always had company. Since becoming aware of this mechanism that problem has disappeared except for the rare time I forget and crack the front windows, and the 'fix' then has been to do as I just posted.

 

Err on the safe side, don't drive with your front windows cracked, catted or not. And if you start to feel your mental state drift and become 'sleepy' beware and take immediate action. You cannot defeat carbon monoxide's effects, you have to either remove yourself from it, or it from you.

[tommypenguin]

Since installing the Cobb DP w/HFC there have been zero smell issues. Before that I was running all decatted stock pipes. It was with those that the issue was revealed.

 

Regardless of whether you can smell the exhaust or not the carbon monoxide will remain, assuming as I do that it is there. Why wouldn't it be, cats don't remove carbon monoxide. Therefore whether you go with a high flow performance cat or not remain aware of the issue and you should be ok.

 

By 'illegally' running catless I became aware of something that has bothered me for many years. Only on long drives, during which I had my front windows partially opened for ventillation and communication with the outside, especially in the mountains, I would sometimes become terribly and inexplicably sleepy. Nothing except stopping and getting out for a while helped. It wasn't lack of sleep. I always had company. Since becoming aware of this mechanism that problem has disappeared except for the rare time I forget and crack the front windows, and the 'fix' then has been to do as I just posted.

 

Err on the safe side, don't drive with your front windows cracked, catted or not. And if you start to feel your mental state drift and become 'sleepy' beware and take immediate action. You cannot defeat carbon monoxide's effects, you have to either remove yourself from it, or it from you.

 

With a cat in the downpipe, it will burn up the fuel in the cat as opposed to it going through unburnt getting cooked off in the piping? Forgive my ignorance... my knowledge of cats are very limited. What I know is that if I recall in the cat, the cat has a nickel lining and that the cat when heated converts carbon dioxide to carbon monoxide? Regardless I will have fumes coming into the cabin because of the vents in the trunk, my question is why will the cat prevent me from smelling the exhaust?

[SeeeeeYa]

With a cat in the downpipe, it will burn up the fuel in the cat as opposed to it going through unburnt getting cooked off in the piping? Forgive my ignorance... my knowledge of cats are very limited. What I know is that if I recall in the cat, the cat has a nickel lining and that the cat when heated converts carbon dioxide to carbon monoxide? Regardless I will have fumes coming into the cabin because of the vents in the trunk, my question is why will the cat prevent me from smelling the exhaust?

 

It is actually the reverse, changing CO to CO2. But the process is not perfect, cats only reduce CO by about 80%, and I doubt anyone is willing to breathe the exhaust of any car even when it meets federal standards. Carbon monoxide is just that toxic. That smell is your clue that there is a LOT of unconverted exhaust, thus a LOT more carbon monoxide.

 

Our cars have ventillation that allows exhaust to enter the interior, relying on imperfect, ever degrading catalytic converters and engine controls to prevent that exhaust from killing us. Give me a break. Do you really believe that continuously inhaling the exhaust of the newest and finest working automobile is safe? Not.

 

Good read: http://chppm-www.apgea.army.mil/documents/FACT/65-017-0503.pdf

 

Note especially the line that reads, "Gasoline engine exhaust, even with a catalytic converter, can produce potentially lethal levels of carbon monoxide."

 

How much of this potentially lethal level does it take to make us unable to drive properly. Personally I am not willingly signing up for one iota. But it appears that driving a car gives us no such choice given the spectrum of circumstances driving entails. But forewarned is forearmed.

[05pearl]

I have been dizzy in my car lately. No exhaust leaks... I checked the trunk vents and there are four rubber flaps on each vent. On my drivers side vent, one of the flaps has deformed and is always curled upward, leaving 1/4 of the vent always open. I only have one cat on the downpipe.

 

Do you think this is why I have been getting dizzy?

[qikslvr]

I have been dizzy in my car lately. No exhaust leaks... I checked the trunk vents and there are four rubber flaps on each vent. On my drivers side vent, one of the flaps has deformed and is always curled upward, leaving 1/4 of the vent always open. I only have one cat on the downpipe.

 

Do you think this is why I have been getting dizzy?

 

I have one HFC in my DP and get some fumes once in a while. Here is my solution to cabin fumes. First off, I never just crack or open just the driver window as it sucks fumes in from the trunk and directs them towards the drivers window. I almost always have the rear passenger window cracked a little(1"-2") so the fumes will suck out the rear of the cabin. With both the passenger rear window cracked and the drivers window open; it creates a little cross breeze that sucks the fumes out the rear window.

 

My other solution on days when it's raining or snowing; is to keep all the windows closed and turn the vent/heat/ac on "fresh air" mode and keep the fan on 2-3 bars. This feeds air in through the dash and forces the air out of those trunk vents. It just seems like our cars create a vacuum in trunk and suck the exhaust into the cabin with just the drivers window open. Sucking fumes(even weak ones) can/will make you dizzy.

[05pearl]

I duct taped the bad flap area on the one trunk vent and it seems to have helped some. I will try your advice on the rear windows / fresh air settings as well.

 

I am amazed that the trunk vents could cause an issue like this. As SeeeeeYa said - very poorly designed and potentially dangerous. Another thanks to this website as I never would have found this problem.

[captainobvious]

I have to chime in here. It seems mine has become more noticable. I dont have any aftermarket parts on yet, but i have a new Up Pipe, Downpipe new gaskets to install when ready. It seems mine is more noticable when the car is sitting idle and not moving. If i change the HVAC controls to recirculate the smell goes away, if i leave it on fresh the car starts to smell.

 

Will changing the up pipe and the downpipe and doing all new gaskets fix it? If not ill take it to my mechanic and have him give it a once over.

[Gire]

Crazy bump...

 

 

But honestly I too have just started to get the cabin smell over the last couple weeks. I`ve had a catless UP and shorty DP installed for 4 years without issue. Never a smell.

 

Now, when the climate controls are on, I get doused with exhaust smell when at idle.

 

I`m thinking it`s a gasket issue, or a leak in the engine bay area. I`m taking my car to the dealer on Weds and having it checked out.

 

 

The smell is non-existant when I turn the climate controls totally off.....