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Old 05-23-2013, 02:58 AM   #1
Faster12's Avatar
Drives: 2012 Black ZL1 #1158
Join Date: Apr 2012
Location: Alexandria, VA
Posts: 176
"HIGH FLOW" Catalytic converters

Is there really a such thing. I was looking at some when I came across this little article:

Just in case you can't use the link, the article reads:

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.

I posted all this to ask, is it true? Do they really make any difference or is it just a sales pitch?
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