Interesting Read... "Highflow Cats"

Speedwagon

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Just doing some research on what header and catted mid pipe I want for my mustang application and I stumbled on this.. Something you might already know but just gives you something to think about ... Makes you wonder what people are selling you or arent selling you.


Clearing Up the Myth About High Flow Catalytic Converters
Is there really such a thing as a High Flow or Performance Catalytic Converter?
Read the following story and you might be surprised!

There are many companies on the web today selling what they call a "high flow" or "performance" catalytic converter. We get calls almost everyday from customers wanting to know how much a "high flow" or "performance" catalytic converter will cost for their car. Well this may come as a surprise to some and will really bust the bubble of what some companies are selling, ....THERE IS NO SUCH THING AS A HIGH FLOW OR PERFORMANCE CATALYTIC CONVERTER!! A catalytic converter has no moving parts nor is chambered like a muffler, or have elaborate packing like a muffler. It's interior is not designed to move exhaust gasses along more quickly such as having a spiral core.
A catalytic converter is designed to reduce harmful exhaust gasses...that's all! Basically all aftermarket cats have a ceramic substrate (the guts) that during manufacturing is coated with a solution of platinum, palladium and rhodium. This coating is what causes the catalyst reaction once the converter reaches a certain temperature supplied by the vehicles exhaust gasses. These substrates are made like a beehive honeycomb and are comprised of 400 cells per square inch across their surface. In theory, an aftermarket cat is higher flow than it's O.E. counterpart, because the O.E. converter has a substrate made up of 700 cells per square inch, so the exhaust flow with an aftermarket converter is a little freer, but not dramatically! We do carry a few universal converter numbers that have a 200 cell substrate but they are like I said, universal. They sometimes require extensive welding and cutting of the original exhaust system, so for many applications these are just not practical.

Okay that's it!! There is no Magic "Super Free Flow" Catalytic Converter out there and any company that tries to sell you one is not quite telling you the truth, The sad thing is, there are some web sites claiming they have High Flow Performance Cats, and by the way at a huge inflated price, when in fact all you will be buying is the same converter you would buy anywhere else for half the price. So that's the story in a nutshell. But if you're still determined to find a High Flow catalytic converter or your buddy told you he got one from XXX Auto Parts, try to remember what you've read here and ask some real questions about the product. Like how many cells per inch are across the surface of the substrates or how many grams of precious metal wash coat is baked into the substrate? If it's below 25 say thank you and leave quickly. If the coating is less than a 25 gram mixture the cat will not do the job, and it will set off the check engine light. You might be surprised to find questions like these will throw most sales people for a loop. Most will have no clue what you are talking about, so just be careful. Okay, if you are now totally confused about the myth of High Flow, Go Flow, Mo Flow catalytic converters and would like to talk more about them...give us a call we'd be happy to hear from you.
 
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el jefe 302

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Just doing some research on what header and catted mid pipe I want for my mustang application and I stumbled on this.. Something you might already know but just gives you something to think about ... Makes you wonder what people are selling you or arent selling you.


Clearing Up the Myth About High Flow Catalytic Converters
Is there really such a thing as a High Flow or Performance Catalytic Converter?
Read the following story and you might be surprised!

There are many companies on the web today selling what they call a "high flow" or "performance" catalytic converter. We get calls almost everyday from customers wanting to know how much a "high flow" or "performance" catalytic converter will cost for their car. Well this may come as a surprise to some and will really bust the bubble of what some companies are selling, ....THERE IS NO SUCH THING AS A HIGH FLOW OR PERFORMANCE CATALYTIC CONVERTER!! A catalytic converter has no moving parts nor is chambered like a muffler, or have elaborate packing like a muffler. It's interior is not designed to move exhaust gasses along more quickly such as having a spiral core.
A catalytic converter is designed to reduce harmful exhaust gasses...that's all! Basically all aftermarket cats have a ceramic substrate (the guts) that during manufacturing is coated with a solution of platinum, palladium and rhodium. This coating is what causes the catalyst reaction once the converter reaches a certain temperature supplied by the vehicles exhaust gasses. These substrates are made like a beehive honeycomb and are comprised of 400 cells per square inch across their surface. In theory, an aftermarket cat is higher flow than it's O.E. counterpart, because the O.E. converter has a substrate made up of 700 cells per square inch, so the exhaust flow with an aftermarket converter is a little freer, but not dramatically! We do carry a few universal converter numbers that have a 200 cell substrate but they are like I said, universal. They sometimes require extensive welding and cutting of the original exhaust system, so for many applications these are just not practical.

Okay that's it!! There is no Magic "Super Free Flow" Catalytic Converter out there and any company that tries to sell you one is not quite telling you the truth, The sad thing is, there are some web sites claiming they have High Flow Performance Cats, and by the way at a huge inflated price, when in fact all you will be buying is the same converter you would buy anywhere else for half the price. So that's the story in a nutshell. But if you're still determined to find a High Flow catalytic converter or your buddy told you he got one from XXX Auto Parts, try to remember what you've read here and ask some real questions about the product. Like how many cells per inch are across the surface of the substrates or how many grams of precious metal wash coat is baked into the substrate? If it's below 25 say thank you and leave quickly. If the coating is less than a 25 gram mixture the cat will not do the job, and it will set off the check engine light. You might be surprised to find questions like these will throw most sales people for a loop. Most will have no clue what you are talking about, so just be careful. Okay, if you are now totally confused about the myth of High Flow, Go Flow, Mo Flow catalytic converters and would like to talk more about them...give us a call we'd be happy to hear from you.



:read:
 

'14 Shelby

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Interested to hear one of the vendors chime in. The article does slightly contradict itself, and does not cite any real reliable data or testing. for example flow measured for stock vs. "high flow" vs. straight pipe. Perhaps you left the source out on purpose
 

Speedwagon

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Sizeth3

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Out of curiosity, would a larger diameter cat flow better as it would increase surface area for the substrate? For instance, on a dual 3" exhaust system, 2 cats with a 4" ID that neck back down to 3".
 

Speedwagon

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Interested to hear one of the vendors chime in. The article does slightly contradict itself, and does not cite any real reliable data or testing. for example flow measured for stock vs. "high flow" vs. straight pipe. Perhaps you left the source out on purpose

What I am concerned here is the correct back pressure after installing headers and mid pipe. I don't want to run into engine lights. Also, I'm not really sure that the extra HP (if any) would be worth the cost over all. So, I'm thinking about keeping the OEM cats to be plugged back into my system. This way I know they'll work and wont cost me any more money. My other thought is that since I will keep my pony in the stable over the winter months and not put 5K miles on it that I would be exempt from emissions all together. Unless I fail the visual inspection. Some say to hallow out the cats and run them straight for the visual. Not sure how you would do that but I sure it can be done. Anyway.. those are some of what I have been contemplating.
 
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KonaFifty

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You have to remember that he said universal and that it takes extensive welding and cutting...what most vendors sell as a high flow cat for x amount of dollars is the labor and welding they put into those universal cats to make them "car specific". You can probably go to a custom shop and have them hack at your system but most vendors are selling bolt on units or units made for their system...
 

'14 Shelby

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OP if you are not installing Long Tubes (think you had a thread on here about that??) then I would say the high flow thing isn't really an issue. Just keep stock cats or go straight (off road) pipes. Many guys have indicated several times that the off road X or H pipe brings about as much HP as does Long Tubes with Catted X/H. Think the numbers around 45 HP'ish for either set up.

If what the article says is true than my set up should (in theory) be able to pass emissions here in NJ. Based on the pure arouma of raw fuel at times, I highly doubt that
 

Speedwagon

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OP if you are not installing Long Tubes (think you had a thread on here about that??) then I would say the high flow thing isn't really an issue. Just keep stock cats or go straight (off road) pipes. Many guys have indicated several times that the off road X or H pipe brings about as much HP as does Long Tubes with Catted X/H. Think the numbers around 45 HP'ish for either set up.

If what the article says is true than my set up should (in theory) be able to pass emissions here in NJ. Based on the pure arouma of raw fuel at times, I highly doubt that

Yes.. I will be installing long tubes but I wasn't sure if I wanted to retain the OEM cats to save a little money. As I keep researching headers and mid I have come the conclusion that I probably wont be losing or gaining much to really make a difference, so I will stick with the highflow cat. PA sucks when it comes to emissions or I would just go O/R X, but I am stuck with the cats for now.
 
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slick3

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Figured I would chime in a little since I just bolted up a steeda catted X in preparation for my kooks shorty install. 1800 miles on a road trip and 200 of dd and still no light. No tune on the car right now. Im in california so the shorty headers are really my only option to stay "legal". The catted X was more for sound if anything. I have baselined my car and planned on getting it tuned shortly so im sure I will see if I picked up some power with these voodoo cats.

Cats were stamped Kooks not sure what cell count they are but they definitely smell a little more than the stock setup hence I would like to think they are flowing a little better....Also, could be a placebo but they car seems easier to drive with the new x pipe, going in between shifts it feels like it holds rpm a little better and makes the drivability on the street at low rpm a little easier. Did I mention it sounds insane with my corsa sport quads? lol

Moral of the story I think the 400 bucks I spent on it was worth it, FOR ME.
 
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momogt

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I have high flow cats welded in I only paid 30.00 for each and 40.00 to have them put on they are a 400 cell I have had them for a year now no issues at all I had a cat delete the smell and the sound was not good added these cats problem solved whether or not I gain power or lost power really cant tell a difference either way but I am very pleased
 

lpheaven

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On my 12 Boss I have Kooks shortys and jegs ss deletes. I actually freakin love the smell and sound. When it comes time, there are a ton of shops i can get a sticker slapped on for 100 bucs. Go to a car show or 2 and ask around. Worst case scenario, ill throw the cats back on and drive through the dmv. I'm modding my car for performance and tuned properly plus with all the a/f sensors, im so close to stoich anyway, it doesnt really matter to me. At the end of the day I think cats are useless now - design never improved, only work when hot etc
 

TrackpackGT

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I'm quite sure there are dyno numbers before and after high flow cats, although most will have larger diameter x/h pipes along with those. Either way, no one would buy a larger mid section pipe and install OEM cats that are stupid expensive.
 

lpheaven

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I'm quite sure there are dyno numbers before and after high flow cats, although most will have larger diameter x/h pipes along with those. Either way, no one would buy a larger mid section pipe and install OEM cats that are stupid expensive.

Im sure they are close but anyone with a moderate understanding of combustion theory, and an understanding of engine control systems knows that a properly electronically tuned engine burns many times cleaner than the federally mandated system. Some european contries won't even allow california smog equipped vehicles in their country because they are so dirty(hydrogen sulfide). At our current level of technology it is abundantly apparent that it has nothing to do with clean air, and everything to do with $$$. **** the fed mandate. Modern vehicle's computers are now so sophisticated that it can vary the pulse of every injector by 1/100th of a gram every single rotation of the engine or more. Modern cars cats use 10-15% more fuel to keep em hot
 

'14 Shelby

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Yes.. I will be installing long tubes but I wasn't sure if I wanted to retain the OEM cats to save a little money. As I keep researching headers and mid I have come the conclusion that I probably wont be losing or gaining much to really make a difference, so I will stick with the highflow cat. PA sucks when it comes to emissions or I would just go O/R X, but I am stuck with the cats for now.

Your OEM cats will not bolt up with Long Tubes. Shorties - YES, unless youre having the OEM mid pipe cut to fit & welded to fit.
 
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