I've always been wary of getting a HFC or test pipe for the exhaust smell. I drove behind a WRX that obviously had a test pipe and the smell was awful.

 

I've got a test pipe with my HKS HIGH power dual and there's no smell or soot and it sounds fantastic without being loud.

 

The berk HFC clearly flows more than the stock cat, you can see the difference when the car switches from low-speed to high-speed fuel maps.

 

By most standards the stock cat is a high flow cat, but of course it is possible to make one that is even less restrictive. The stock cat was designed to start working effectively at a lower temperature and uses much better honeycomb materials than most car's catalytic convertors, but the Berk and other HFC simply put less material in the way. The stock cat has two honeycomb elements, where most HFC only have one.

 

So guys if I put a test pipe on my full standard stock exhaust system will it make it loud because I really don't want a loud car. Never knew smell was an issue. My car was run in well so doesn't burn oil so hoping this wouldn't be an issue with my car I don't know? Also with a TP will I notice much of a difference in power? Like the fact that TP are a cheap, simple, and quick mod!

 

No, it will not be loud at all. TP adds a pleasant throaty sound to the note (kind of like a nissan vq engine), but only a touch of increased volume.

They do smell pretty bad, but YOU get used to it. I don't smell mine at all anymore, but everyone else still says it stinks.

You will gain several hp, but performance gains will be negligible.

I have no problem passing emissions with my berk TP and stock O2 sensor. They just plug into the OBDII and since my car isn't throwing an O2 cell, I pass. There is no visual inspection here.

 

cheap HF cat

Expensive Berk HF cat

So, I keep reading the HF cat is an expensive option. I looked on eBay. Whats the difference between these 2 other than price? Is it just the brand you pay for with Berk or is the top one very ?

 

Although I haven't tried these parts, on a previous car, a Civic 1.8VTi my experience of cheap cats and lambda sensors wasn't great. They worked for a year or two and then packed in. Whether they're worth it depends on how much you save up front and how long you plan to keep the car for.