Depo Racing Focus RS Hi Flow Cat 100 cell . In stock cars, the stock catalytic converter is the primary choking point to make power with a turbo. In order for the turbo to spool fast and compress the air for the engine, the exhaust needs to escape freely. If the exhaust stops flowing the turbo stops moving efficiently.
If you new to the Focus RS welcome, I’m not new to making downpipes. My parts are on world record Evo’s and Focus St’s
a. 304 Stainless Steel
c. good for 500+ whp
e. Bolts up to stock or aftermarket exhaust
f. Free flowing 100 cel metal substrate + cuts out gas smell
g. Track / Off road use Only
– See more at: https://deporacing.us
Hi Flow Cat 101
ALL brands of HI FLOW CATS are not meant to clean the exhaust and pass emissions like a stock cat, they
would not be hi flow at that point. The goal is to knock out the gas smell and flow a ton of exhaust so you can
make good power gains like a Catless does. The metal substrate needs to be hot to do this, so all Hi Flow Cats
brands will have smell until the cat is warmed up.
As far as passing emissions and throwing a CEL code , all Brands will do this also. Just like a Catless pipe the
cars sensors will know the exhaust is not clean. This does not mean you can not get rid of the CEL and pass
emissions. For instance an Evo 8 ran a full 3″ catless exhaust, with a extended the O2 bung it kept the sensor out
of the flow of exhaust and with No CEL it passed emissions.
So with a Hi Flow Cat or a Catless you can trick the ECU by extending the bung, they even make O2 – 90
degree extenders now. Or you can have the tuner disable the secondary sensor and it will not throw a CEL. At the
end of the Day a HFC with only cut the gas smell ir wont stop a CEL any better then a Catless.
Some States ban the use of HFC or Catless pipes and they are only allowed for off road use. It is up to the user
to know his state laws and follow them.