I heard that gutting a HFC is basically like a test pipe performance wise. They have different shapes/diameters so how can that be? I'm thinking the airflow in the hollowed cat doesn't flow as fast as through a straight pipe.

 

Im sure a testpipe would still flow better than a gutted HFC.If you are concerned with getting the most flow than just go with a testpipe and call it a day.

 

thats what i was thinking.. even better get the RRErallycat! test pipe with heat shields ftw ! kinda pricey tho

 

check here
https://www.evolutionm.net/forums/sh...d.php?t=317191

 

if you have a HFC, dont gut it please. HFC is worth alot more money, its wiser to sell it and buy a test pipe (and pocket the $)

 

yeah or just run the HFC.

 

HFC...same performance or super close to it & it's legal. Test pipe is not street legal of course ( I have a test pipe on mine and haven't been ticketed for it thankfully)

 

I wouldn't say same performance....there can be a big difference depending on what type of hfc it is.

All high flow cats are not created equal

 

too bad HFCs arent legal in cali .. I think ima get a rallycat just so I don't have to be all paranoid (no cat tickets = big $$$). and keep my hfc just in case i cant stand the smell or sound of the rally. thought about getting a test pipe and welding shields cus its cheaper but don't want any rattling in case of bad welds

 

A test pipe is a test pipe, as long as the flanges line up and tighten nicely to the cat back and down pipe. So, if you buy a test pipe even check out ebay you can get one really cheap. Like i said as long as its stainless steel all it is is a pipe! Sell your HFC and make some money back!

 

Ain't that the truth. Check this out...

Here are some recent dyno results from NorCal showing the superiority of the 100 cell cats:


+22whp/+19tq on a Mustang Dyno. Ultimate HFC & MBC vs. 100 cell race cat & ECUboost.

http://www.norcalevo.net/index.php?o...2280#msg422280

+21whp/+11tq on a Mustang Dyno. VI$H you-know-who HFC vs. 100 cell race cat and Sun Hyper Force.

http://www.norcalevo.net/index.php?o...4330#msg424330