Exhaust fumes in car

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I suffered from exhaust fumes in my convertible with a .245/ .250 duration cam in a stroked 408 Magnum. It was so bad that people walking by would wave their hands in front of their face to fan away the smell wafting over to them on the sidewalk. The car was even EFI'd with a factory JTEK and a tune.

I welded on a set of High-Flow Racing cats behind the header collectors and before the crossover, and the smell was gone. I could not detect any power lose or sound change after. The were about $100 each at Summit.

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What size exhaust is that and do you have a part number for those cats?
 
Are you saying having a large cam with significant overlap, where both valves are open at the same time, has nothing to do with tail pipe emissions/raw fuel smell?
It be hard to believe that the idle bypass or lack there of wasn't adding to the excessive emissions in the vehicle.

Though adding the high flow "cats" is an interesting concept.
 
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It be hard to believe that the idle bypass or lack there of wasn't adding to the excessive emissions in the vehicle.

Though adding the high flow "cats" is an interesting concept.
"High flow cats" I always chuckle to myself about that, because there is no such thing. LOL
 
Get a friend and throw him in the trunk with a lit cigarette and a flashlight and gently drive around. Let him take the cigarette all around the trunk seal, around the back side of the tail lights and anywhere else that might be a suspect for a leak. He will find it.
Hilarious! Hopefully the term "friend" is used loosely...
 

jump in your trunk have a buddy close by close the lid and see if theres any day light, my old 69 DART did just what you said.thats how i found my fummmmssss.
Use a teenager, or even better your wife. That way you can also get some peace and quiet…..
 
Hmm... there must have been some improvements since the can full of pellets...
Very, very little. A converter requires heat in order to remove NOX gasses. A lot more heat than a "normal" exhaust produces. That extra heat comes from the restriction of the media. Whatever it is. There ARE no high flow cats. I don't give chit what the BS marketing says. Believe what you will.
 
Very, very little. A converter requires heat in order to remove NOX gasses. A lot more heat than a "normal" exhaust produces. That extra heat comes from the restriction of the media. Whatever it is. There ARE no high flow cats. I don't give chit what the BS marketing says. Believe what you will.
I don’t disagree with you.
 
What size exhaust is that and do you have a part number for those cats?
Full TTI with 3 inch out the back. The cats are 3"inlet/outlet with a 4" body. You can actually see through the metal hybrid matrix, so significantly more flow than a factory style converter. They are designed differently for different end results. One for maximum emissions reduction and the other for higher flow at the expense of maximum emissions control.

Even though I was running the factory JTEK computer on my 408, I used an electronic O2 simulator to get a consistent square wave and avoid the check engine light the CEL code would likely have popped up. There was no noticeable drop in power output from the engine.


For the uninformed:

A 100-cell catalytic converter flows significantly better (less restriction, more power) than a 200-cell one because it has fewer internal passages (cells per square inch) for exhaust gases to navigate, but it offers less surface area for emissions control, making it more prone to triggering a Check Engine Light (CEL) and potentially failing emissions tests. A 200-cell cat balances better flow than stock (600-800 cells) with improved emissions cleaning, making it a common choice for performance street cars, while 100-cell cats are for maximum flow in motorsport.
 
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Full TTI with 3 inch out the back. The cats are 3"inlet/outlet with a 4" body. You can actually see through the metal hybrid matrix, so significantly more flow than a factory style converter. They are designed differently for different end results. One for maximum emissions reduction and the other for higher flow at the expense of maximum emissions control.

Even though I was running the factory JTEK computer on my 408, I used an electronic O2 simulator to get a consistent square wave and avoid the check engine light the CEL code would likely have popped up. There was no noticeable drop in power output from the engine.


For the uninformed:

A 100-cell catalytic converter flows significantly better (less restriction, more power) than a 200-cell one because it has fewer internal passages (cells per square inch) for exhaust gases to navigate, but it offers less surface area for emissions control, making it more prone to triggering a Check Engine Light (CEL) and potentially failing emissions tests. A 200-cell cat balances better flow than stock (600-800 cells) with improved emissions cleaning, making it a common choice for performance street cars, while 100-cell cats are for maximum flow in motorsport.
I got your uninformed hangin and swangin. Here's a little tidbit for the uninformed. It's called marketing. You believe the BS. That's why they throw it out there. To sucker weak minded people in and make them believe anything. I don't care what any sales pitch, articles or graphs and charts say.
 
Full TTI with 3 inch out the back. The cats are 3"inlet/outlet with a 4" body. You can actually see through the metal hybrid matrix, so significantly more flow than a factory style converter. They are designed differently for different end results. One for maximum emissions reduction and the other for higher flow at the expense of maximum emissions control.

Even though I was running the factory JTEK computer on my 408, I used an electronic O2 simulator to get a consistent square wave and avoid the check engine light the CEL code would likely have popped up. There was no noticeable drop in power output from the engine.


For the uninformed:

A 100-cell catalytic converter flows significantly better (less restriction, more power) than a 200-cell one because it has fewer internal passages (cells per square inch) for exhaust gases to navigate, but it offers less surface area for emissions control, making it more prone to triggering a Check Engine Light (CEL) and potentially failing emissions tests. A 200-cell cat balances better flow than stock (600-800 cells) with improved emissions cleaning, making it a common choice for performance street cars, while 100-cell cats are for maximum flow in motorsport.
Awesome, thanks for the information!
 
I got your uninformed hangin and swangin. Here's a little tidbit for the uninformed. It's called marketing. You believe the BS. That's why they throw it out there. To sucker weak minded people in and make them believe anything. I don't care what any sales pitch, articles or graphs and charts say.
:poke::rofl:
 
After spending most of last year trying to get my 69 Cuda notch with a 318 , 904 trans running, this year was finally able to get to some car shows. Just yesterday drove about 40 miles and back from a very large show [ Gasket Goons near Hellertown Pa.] driving both ways with windows down keep getting a strong exhaust order into car. Car has a 2 1/2 stainless steel exhaust, I see/hear not leaks in system. Had noticed this prior also, have exhaust tips clamps on end of pipe, moved them out to extend them hoping that would help but did not. I am not sure what else to look at, trunk is sealed [ finished off with trim panels] , all door seals are new. Could engine just be running that rich/lean [ no black smoke seen any time ] to cause this issue?
Just something to check, the lower steering column seal. Mine was toast and I was getting engine fumes/smells in the cabin.
 
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