hi-flow cats??

sweetEA · 21-06-2006, 06:28 PM

simple question is a high flow cat nesscesary ie. if i put extractors and a cat-back exhast system on would the standerd cat make all of that pretty pointless??

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sphell · 21-06-2006, 06:31 PM

no, apparantly the standard cats flow pretty well. But if yours is old and lookin a bit chewed, then I'd just get a new one and be done with it.

EFDream · 21-06-2006, 06:37 PM

If your car is really old you probably want to replace the cat anyway and the hi flow will definately be worth investing in if your going to do everything else.

sweetEA · 21-06-2006, 06:43 PM

thanks guys also what are likely power gains with a full exhaust system ie extractors+hi-flow cat + cat back???

EB Pete · 21-06-2006, 06:44 PM

whats the difference bettween the hi flow and normal ones? eg diameter sizes, material? differences other then the fact that one flows more.

mcflux · 21-06-2006, 06:54 PM

For my 5.0's exhaust, I opted for standard cats. My system is slightly oversized for the engine's current output (twin 2.5" into single 3"), and the standard cats are definitely up to the job. High-flow cats should be for motors built to rev, or motors that gulp down a lot of air/fuel (ie forced induction), rather than near-stock setups.

I'm assuming the same would apply to the I6.

mcflux · 21-06-2006, 06:57 PM

Quote:

Originally Posted by EB Pete

whats the difference bettween the hi flow and normal ones? eg diameter sizes, material? differences other then the fact that one flows more.

I believe the internals of standard cats are around the 2.5" diameter mark, but are flanged to 2.25", or at least this was what my cats were. I had the flanges replaced with 2.5" to match the rest of the exhaust.

Once again, with I6, it could be different ;)

5L · 22-06-2006, 01:30 AM

with I6 it is the same im sure, 2.5" cats but the flange is 2.25". my standard cat was stuffed so i got a hi-flo. the only thing i really noticed was it made a better exhaust noise, and it smells a bit more.

MK120C · 22-06-2006, 09:21 AM

Quote:

Originally Posted by sweetEA

simple question is a high flow cat nesscesary ie. if i put extractors and a cat-back exhast system on would the standerd cat make all of that pretty pointless??

:

The standard cat is larger in size than the hi-flow cat. I did this mod at home took the cat of my EL then cut both pipes from the end of the cat which are 2.25in, once this was cut off it was pointless welding on the 2.5in flange because you still have about an 1.5in of 2.25in jammed into the cat the only way to get it out was to punch it out, Im not sure if muffler shops go to the trouble of doing this. The inside dia is 2.5in. I have had my EL since new and the inside of the cat still looks new 'by the way' when you look inside the cat it really is impossible to see any restriction you can see all the way to the other side the honey cone in there is very open. Save yourself a dollar use the same cat. I have extractors and 2.5in system in my case it made F... ALL differance doing the cat.