Need a precise answer on CAT specs

zeno · Feb 6th, 2003, 02:05 PM

I was wondering if anyone had a precise number of how much hp you would gain w/ a hi-flow CAT on a sr20de engine. There does not seem to be a exact answer...through my time on the forum most people claim almost no gain w/ an upgraded CAT. A search revealed mixed results w/ some people claiming 1-2hp while others gained something like 5hp. Addtionally, se-r.net is making the claim that a hi-flow CAT is good for about 5-10hp! Which is it damn it! How much does an upgraded header and exhaust play in the equation? I know the stock CATs have little back pressure and conventional wisdom is not to mess w/ them but I want the record set straight regarding gains from hi-flow CATs.

bahearn · Feb 6th, 2003, 03:20 PM

Realize that a lot of SE-R.NET is seven years old, back when people believed $tillen's horsepower numbers.

Also realize there is no exact hp difference, it all depends upon state of tune and whether you're squeezing. I tend to believe 1-2 hp for N/A, at best.

PhattyB13 · Feb 6th, 2003, 07:54 PM

well I am in the process of my swap and I have been calling around to different exhaust shops in town.. basically exhaust work isnt cheap..most places are quoting me around 600 bones.. and that includes 2.5" piping all the way back, new flex pipe in my down pipe, my muffler I already have, and a high flow cat..

anyways the kicker is that 375 bucks of that is for the high flow cat... I just dont see paying 375 for something that may only give me 1-2 hp...

with me since I am going from a 1.6 to 2.0 I need to get a custom exhaust.. I already have a hotshot header as well..

so I was wondering if you all thought it was worth it.. what kinda of cat is everyone else running with a custom exhaust.. let me know thanks..

mpg9999 · Feb 6th, 2003, 10:22 PM

The stock nissan cat has excelent flow, and there is no need to upgrade unless possibly you are boosting.