Cats, Headers, Flow, Sound
Thread Starter
Joined: Mar 2007
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Cats, Headers, Flow, Sound
Hi Everyone!
I was planning on purchasingLongtube headers and doing the install myself. Obviously a big purchase and based off the posts here, a realBEAR of a job.
I live in Florida where they don't have emissions control. I see on some websites they sell catless headers and disclaim "off-road use only".
My buddy who lives inCalif says if he were me, he'd just cut out theCats on my existing system- That's where the restriction is. Doing so would save me the money and the day ++ labor. Eliminating the cats would give me the airflow and the sound i am looking for.
Im new to all this, posting here to hopefully get some feedback of pro's vs con's, if it will work, how it will sound, legal ramifications...basically anyadvice or feedback i can get on the subject.
I know a good welder, so cutting them out and putting it all back together shouldnt be that big a hassle.
I was planning on purchasingLongtube headers and doing the install myself. Obviously a big purchase and based off the posts here, a realBEAR of a job.
I live in Florida where they don't have emissions control. I see on some websites they sell catless headers and disclaim "off-road use only".
My buddy who lives inCalif says if he were me, he'd just cut out theCats on my existing system- That's where the restriction is. Doing so would save me the money and the day ++ labor. Eliminating the cats would give me the airflow and the sound i am looking for.
Im new to all this, posting here to hopefully get some feedback of pro's vs con's, if it will work, how it will sound, legal ramifications...basically anyadvice or feedback i can get on the subject.
I know a good welder, so cutting them out and putting it all back together shouldnt be that big a hassle.
Charger Moderator
Joined: Apr 2006
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From: Allen TX
RE: Cats, Headers, Flow, Sound
I've read posts were people are happy after running w/o cats and other posts where someone changed mufflers and lost low end torque due to too much airflow and not enough backpressure.
In the early stages of my exhaust I tried several things; one was swapping out the suitcase muffler and installing another free flow muffler. I ended up loosing low end torque, it was noticeable imediately after the swap. I got low end torque back when I put on the Corsa.
Legally I would hate to be caught without cats, it's a heaftyfine. Some have shelled the cats so they look fine from an exterior examination but on the inside there’s nothing but an empty tube.
In the early stages of my exhaust I tried several things; one was swapping out the suitcase muffler and installing another free flow muffler. I ended up loosing low end torque, it was noticeable imediately after the swap. I got low end torque back when I put on the Corsa.
Legally I would hate to be caught without cats, it's a heaftyfine. Some have shelled the cats so they look fine from an exterior examination but on the inside there’s nothing but an empty tube.
) want to know.
Charger Moderator
Joined: Apr 2006
Posts: 3,109
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From: Allen TX
RE: Cats, Headers, Flow, Sound
Here's a fellow California chargers experience w/no cats.
I hollowed out my Cats rather than replacing them with a straight pipe, as having no cats at all are automatic impound if a visual inspection ever arises in California. My first plan was to simply run a straight pipe through the catalytic converters, but that proved to be difficult due to the bends, so I simply hollowed out the cats and hoped for the best. I was going to fabricate a new mid pipe that is straighter than stock and either 2.5" or 3" in diameter, but as I don't think the gains would be much at all, I used an extra set of stock mid pipes which greatly simplified the process.
Will it pass smog? No. Not at all. I have my stock set of mid pipes with untouched catalytic converters that I can reinstall in four years for smog.
Impressions?
WOW!!! The sound of the Borla 125 exhaust completely changed -- for the better!! It used to be too 'smooth' and muffled.. and it is now way more throatier and a little more raspier -- sounds more old school -- the way a HEMI V8 should sound! I can also feel a lot more power in the low and mid range as well as a ton more throttle response!
I welded up the driver side mid pipe first and installed it while leaving the stock passenger side intact. I started it up and revved it with my hand over each of the rear tips, and holy crap! The driver side felt like it was pushing out at least double the airflow than the passenger side, with the stock mid pipes.
I have only one regret: I didn't do this mod a year ago.
Regarding CEL's: None so far. I'm crossing my fingers and hoping for the best. I used one HELP! Sparkplug Anti fouler 42002 (Drilled out with 1/2" drill bit) on each side to get the O2 Sensors out of the mid pipes a bit.
Will it pass smog? No. Not at all. I have my stock set of mid pipes with untouched catalytic converters that I can reinstall in four years for smog.
Impressions?
WOW!!! The sound of the Borla 125 exhaust completely changed -- for the better!! It used to be too 'smooth' and muffled.. and it is now way more throatier and a little more raspier -- sounds more old school -- the way a HEMI V8 should sound! I can also feel a lot more power in the low and mid range as well as a ton more throttle response!
I welded up the driver side mid pipe first and installed it while leaving the stock passenger side intact. I started it up and revved it with my hand over each of the rear tips, and holy crap! The driver side felt like it was pushing out at least double the airflow than the passenger side, with the stock mid pipes.
I have only one regret: I didn't do this mod a year ago.
Regarding CEL's: None so far. I'm crossing my fingers and hoping for the best. I used one HELP! Sparkplug Anti fouler 42002 (Drilled out with 1/2" drill bit) on each side to get the O2 Sensors out of the mid pipes a bit.
Thread Starter
Joined: Mar 2007
Posts: 13
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RE: Cats, Headers, Flow, Sound
Thanks for the quick replies.
I've gotta believe going catless or hollowed out will give codes. As much as i would like to save the money on this, Im six payments in and still owe like 30 grand...if im gonna do it, i wanna do it right. Was just searching for an easy way out.
SLP looks like the best choice. They are pricey, but a good steel, jet coated, the highflow cats are supposed allow good flow, they say that they maintain factory ground clearance.
Mopar looked good at first and although they are somewhat inexpensive compared to the others, along with the idea that they are the least likely to throw codes - having a smaller collector, not being true longtubes...i read they are a mild steel and i'm not sure how well they will hold up.
Plus going through all the effort to increase flow - might as well go with the ones that appear to have more, i will get the non foulers to help with the ratios.
Side note: i understand i will have to buy two sizes of the non foulers, have read of stacking them? cut out the center on one?? any advice on this, info on the install process of these??
Thanks again,
Hendryk
I've gotta believe going catless or hollowed out will give codes. As much as i would like to save the money on this, Im six payments in and still owe like 30 grand...if im gonna do it, i wanna do it right. Was just searching for an easy way out.
SLP looks like the best choice. They are pricey, but a good steel, jet coated, the highflow cats are supposed allow good flow, they say that they maintain factory ground clearance.
Mopar looked good at first and although they are somewhat inexpensive compared to the others, along with the idea that they are the least likely to throw codes - having a smaller collector, not being true longtubes...i read they are a mild steel and i'm not sure how well they will hold up.
Plus going through all the effort to increase flow - might as well go with the ones that appear to have more, i will get the non foulers to help with the ratios.
Side note: i understand i will have to buy two sizes of the non foulers, have read of stacking them? cut out the center on one?? any advice on this, info on the install process of these??
Thanks again,
Hendryk
Charger Moderator
Joined: Apr 2006
Posts: 3,109
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From: Allen TX
RE: Cats, Headers, Flow, Sound
Here's a good therad on the non fouler topic, see post # 15.
https://dodgeforum.com/m_539943/tm.htm
https://dodgeforum.com/m_539943/tm.htm
Record Breaker
Joined: Oct 2005
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RE: Cats, Headers, Flow, Sound
Guys are getting codes both ways Dave,im gonna go to 3 spacers on the rear when my new o2 comes in.Then Im fixin the little snakes I have got under there replacing them with ponies.My Borla is real deep and throatie now,I have only heard them inside the car not outside yet I cant wait.
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Charger Moderator
Joined: Apr 2006
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From: Allen TX
RE: Cats, Headers, Flow, Sound
Check the thead link in post #5, there's pics of the spacers - non foulers there.
Headers more often then not will throw O2 CEL codes. Some insert the O2 sensors into "spacers" (<= or called "non foulers") which pull the O2 sensor out of the pipe and airflow to help alleviatethe CELs.
Headers more often then not will throw O2 CEL codes. Some insert the O2 sensors into "spacers" (<= or called "non foulers") which pull the O2 sensor out of the pipe and airflow to help alleviatethe CELs.
Thread Starter
Joined: Mar 2007
Posts: 13
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RE: Cats, Headers, Flow, Sound
How about O2 simulators? what is the difference between the non-fouler and the simulator?
I have heard that even with the non foulers, codes are sometimes present. Especially with extreme amounts of air flow-Like the Kooks headers give alot of those, or going catless...looks like that's why Marty is gonna stack three in the rear.
That's why im wondering about the simulators
I have heard that even with the non foulers, codes are sometimes present. Especially with extreme amounts of air flow-Like the Kooks headers give alot of those, or going catless...looks like that's why Marty is gonna stack three in the rear.
That's why im wondering about the simulators