High Flow Cat & Placement
06-01-2005, 02:51 PM
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Ok, I'm almost finished with the entire airflow system. I just need something more. My setup will look like this: AEM Cold Air Intake - Big Bore Throttle Body - Jet-Hotted Airram - 1.8L Cam - Jet-Hotted GT Headers - Downpipe - High Flow Cat - Jet-Hotted Tim's 2.25 'cat-back exhaust.
Is that a good place to have a catalyctic converter for this setup?
If so, will I need to buy an extra O2 Bung for the catalyctic converter?
I found a Catco on ebay with a 2.25' inlet. [Catco Catalyctic High Flow] Will that work well? I mean, the cat will probably be under the car. I don't know if I want it wet or to hit anything. I also don't want to cut anything away from the downpipe but rather have it flange onto the back of the downpipe. Is there any smaller Catalyctic converter I can buy for that location?
Is that a good place to have a catalyctic converter for this setup?
If so, will I need to buy an extra O2 Bung for the catalyctic converter?
I found a Catco on ebay with a 2.25' inlet. [Catco Catalyctic High Flow] Will that work well? I mean, the cat will probably be under the car. I don't know if I want it wet or to hit anything. I also don't want to cut anything away from the downpipe but rather have it flange onto the back of the downpipe. Is there any smaller Catalyctic converter I can buy for that location?
06-01-2005, 02:56 PM
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The hotter the exhaust gases are, the better the cat works... so right off the downpipe is the best location if your looking for emissions results.
Restriction-wise, location really doesn't matter too much, for a street car using cats anyway.
Restriction-wise, location really doesn't matter too much, for a street car using cats anyway.
06-01-2005, 03:43 PM
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What is the diff hp wise between hi flow cats OEM cats and just a test pipe, if you have headers and a 2.25 cat back? I saw on a tv show on the speed channel where a turbo charged nissan, not sure what kind, but it got 5 whp between a stock cat and test pipe, but I dont want a buzz created by the test pipe.
06-01-2005, 03:57 PM
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On my previous car (Opel Vectra 2.0, 1991 year, 150 hp in stock) I noticed difference when changed my stock cat to test pipe. I didn't feel anymore hp loss when I turned ON A/C. But probably I did it cause that catalityc was old.
To get rid of the buzz - you can wrap test pipe with special tape.
To get rid of the buzz - you can wrap test pipe with special tape.
06-01-2005, 04:15 PM
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oh i want anything but stock. the stock cat is old and ratty. haha... and the overall piping is 2.25' so it's slightly bigger than stock.
the best place to put a cat is where the stock cat is, but the headers will send a lot of exhaust flow out through that area and i don't want to restrict exhaust that early on. so it's definitely going to be at the back end of the downpipe. the problem is that it will be under the car. so if you drive, the car might hit a manhole or debris or something of that stature and ruin my total exhaust. i wish cats were flat!
the reason i would like to purchase a cat is because they're darn strict here in Maryland on emissions. i would also like that the exhaust not be so noisy because sound what a test pipe would let come through.
this brings me to my next question. test pipes are illegal right? i mean they're just extensions?
REDZ mentioned Magnaflow Cats. Does anybody know if those are smaller ones?
the best place to put a cat is where the stock cat is, but the headers will send a lot of exhaust flow out through that area and i don't want to restrict exhaust that early on. so it's definitely going to be at the back end of the downpipe. the problem is that it will be under the car. so if you drive, the car might hit a manhole or debris or something of that stature and ruin my total exhaust. i wish cats were flat!
the reason i would like to purchase a cat is because they're darn strict here in Maryland on emissions. i would also like that the exhaust not be so noisy because sound what a test pipe would let come through.
this brings me to my next question. test pipes are illegal right? i mean they're just extensions?
REDZ mentioned Magnaflow Cats. Does anybody know if those are smaller ones?
06-01-2005, 04:25 PM
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I meant replacing it after the downpipe... where your second cat is. That cat is already there and doesn't get beat up/torn by debris, so why should an aftermarket one?
It would be almost impossible to bottom out your entire exhaust... if you look under the car, the exhaust follows a route that is indented into the body. A cat would hang down maybe a few inches below that. You would more than likely brake a hell of a lot more things before you got to the cat.
It would be almost impossible to bottom out your entire exhaust... if you look under the car, the exhaust follows a route that is indented into the body. A cat would hang down maybe a few inches below that. You would more than likely brake a hell of a lot more things before you got to the cat.
06-01-2005, 05:00 PM
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QUOTE
I meant replacing it after the downpipe... where your second cat is. That cat is already there and doesn't get beat up/torn by debris, so why should an aftermarket one?
we have a second cat? i thought we only had one! i guess it will hang just a little bit low. maybe my mechanic can work something out with the fitment. i mean, it should fit anywhere onto the exhaust line?
QUOTE
You would more than likely brake a hell of a lot more things before you got to the cat.
haha!!!! i feel you on that one. i was thinking of the whole thing shifting or something. but i guess that's not even a problem unless you hit something really hard. my main focus is to pass emissions, produce a sexy noisy but limited sound and make some speed!
06-01-2005, 05:17 PM
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some cats (like or oem cats) dont flow as well as others.... obviously
like hi flow cats which mostly have perforated cores flow a hell of alot better than ones with a louvered core....it can be a bottleneck for high horsepower applications.... if your not going turbo i wouldnt worry to much about it unless you want the extra 1 hp.......
and yea that would be a perfect spot for your cat....
like hi flow cats which mostly have perforated cores flow a hell of alot better than ones with a louvered core....it can be a bottleneck for high horsepower applications.... if your not going turbo i wouldnt worry to much about it unless you want the extra 1 hp.......
and yea that would be a perfect spot for your cat....