I've had/gone through some of the high flow cats mentioned already.

Random Technology high flow cats - got them used from Neffster. They gave me the most power when I dynoed on the dynojet versus when I had the crawford cats. The RT cats also made my Borla exhaust note the loudest at WOT and rasp was equally prevalent (you could really hear it) as well. The passenger side cat eventually blew. I didn't know until I participated in a dyno day in which my A/F was waay off. Took off the cats and when I shake the passenger cat I could hear moving something inside (catalytic converter innards imploded)...and thats when I got them replaced with the Crawford Cats...

Crawford Z Car high flow cats - got these used too from Kpierson. They didn't make as much power as the RT Cats but they lasted longer (approximately 40k miles). No raspiness sound heard from these which I liked. They made my Borla exhaust very deep/bass toned. Eventually the passenger cat blew too. Catalytic converter innards actually imploded and blew threw my Borla exhaust. It was a real pain because my shop, Lokey Infiniti, that worked on the car had to disassemble the entire exhaust and clean out/made sure no debris was left. I then replaced them with the Fast Intentions High flow cats...

Fast Intentions high flow cats - I have the ceramic core cats from this company. Exhaust tone and rasp are similar to the Crawfords. Power is about the same as well (I don't recall my dyno runs, you'll have to ask Jeremy at Performance factory).

All of them had very good quality construction. I'm keeping my fingers crossed and hope these FI cats last a long time...

 

Demonteverde thanks for the great input, you really have me considering now more towards the FI cats. I was leaning more towards Crawfords. What is it that makes them blow up or implode? Is this more prevalent in high output engines like turbocharged or force inducted? Does that decrease the life of the cat?

 

I don't want to jack your thread but are HFCs necessary to get gains from a new exhaust/intake?

 

You can't go wrong with either Fast Intentions or Crawford cats. They are both constructed very well and put down similiar gains on the dyno. RT cats have also fixed their issue as well and now have metallic cores in their cats as composed to their ceramic innards they used to put. As for the technical explanation on why my cats imploded, I can't remember. It was explained to me in detail once but I ran't reiterate what was said to me right now. I would pm Fast Intentions...

the stock cats are a bottleneck and free up some power.
My first mod was my borla true dual exhaust. I dynoed it and made .1 horsepower and no torque change. I added cats/plenum down the road and only then did I actually see gains...

 

Again thanks to all for all your input. so with all this, what's better to have, ceramic or metallic insides in the cat.

 

Nothing, just a nice straight hollow pipe...... Get resonated TP's!

 

the thing about test pipes is the rasping you get from them. not really looking forward to hearing that daily.

 

Metallic innards are better and last longer and will not implode as easily as ceramic

 

i may be selling a pair of cats WITH o2 sensors sometime in the next week or 2, getting rid of mine.

Crawford cats, let me know if your interested in waiting, and dont mind if their used (about 5-7k miles)

 

I was not looking into buying used ones, but pm me with a price and we'll see how it goes. You have not put that many miles on them.

 

They dont rasp as they are resonated. I have heard them on a coupe already with stock exhaust = no rasp

 

i was under the impression that test pipes were know for the rasping, whereas the hf cats, due to the metallic or ceramic innards took away most of that rasping at the sacrifice of hp gain.