I'm getting a performance orientated exhaust system, but it comes with a hollow cat piece instead of an actual cat. So i'll need a cat too, since i want to pass emissions as its required in my state.

Does anyone have documentation of power gains of say a Magnaflow, flowmaster, whatever, vs a OEM or OEM-style converter?

And what about a cat with an even lower cell count, like 200 or 100 per square inch vs magnaflow's 400? Would that prevent me from passing emissions?

 

I don't have any actual numbers...
But i have dynoed a stock h22 with stock cat and a test pipe. Saw less than 2hp difference, but stock engine.

I have also run the magnaflow high flow cats and in Texas they will pass first year, usually pass second year and failed third year every time.

 

That is worrying. Were they ceramic or spun-metallic core cats?

 

They were the very standard Magnaflow/Carsound high flow cats that sell for less than $100. Can't expect a $100 cat to stand up well next to a $700-1100 oem cat...

 

bump for more opinions

 

Just out of curiosity, what are the emissions tests they do on your car and what year/type is your vehicle? Visual? Load bearing dyno, obd2 port hookup only?

If your obd2, you can install an o2 sensor "simulator" or "spacer" on the secondary o2 sensor and it will place the sensor just in the right place in the exhaust stream, that it will give the correct voltage to the ecu that the ecu wants to see from a functioning catalyst, about .65 volts IIRC.
Seen it done once and heard of it being done lots.

Vibrant make one.

 

95 civic, no visual inspection not so much as looking at brake pads or popping the hood. No dynos anymore. Its obd1 so no port hookup, just an exhaust probe and a weird machine that measures RPMs from ontop of the hood.

The exhaust itself actually needs to be clean. At idle, and higher idle.

 

Okay, so guys i made this way, way easier..

18160-RCA-A00 or 18190-RCA-A00
They're cats off a 7th gen v6 accord, the first one is the main primary cat and the second one is precat pipe.. Im gonna asee about measuring the openings diameters tomorrow, but for now i'll hope a v6 person will comment