I have looked at some of the other threads regarding cats but I wanted an opinion in my situation.

I am in an area which is not heavily polluted and does not have emission legal testing... Is there better flow without a cat? Its pretty much toast, and I don't wanna buy a high flow one. Logic says if its not there, theres less resistance, but is there advantages to them that I'm overlooking, eg) backpressure

 

nope you'll gain any where from 12- 15 horses. if there's no testing i wouldn't have one.
you'll want a test pipe though.

 

are you serious?? that seems like a huge gain!

and a test pipe is just a plain pipe that takes it's place, right? or is there anything special about a test pipe?

 

nah it's just a pipe with flanges on the end of it. and yes you do get those gains. the cat is restrictive...very... you'd be surprised in the difference.

 

I don't know about that much of a gain. Barely noticable IMO

 

nah it's 12-15. it's really restrictive. keep in mind that at redline it still has to be able to break down the bad stuff efficiently.

 

is gutting the cat another option, instead of removing it totally? Also, how will this affect the sound of a stock exhaust?

 

if ur running some crazy turbo setup and have the cat on, then maybe 12-15, no way u free up 12-15 by just removing the cat on a stock or close to stock motor

 

i can make test pipes for s13 that are 2,3/4 in made of aluminized steel. then painted black to prevent rust. i can't garenty any surten power gains but it should be any where from 5-15 hp depending on what kind of mods you have. i live in montana so i have no emishons to deal with but i dont now what the laws are in other places so i'll half to say they are desighed for off road use. please email me if interested.

if this cant be posted hear sorry, just seamed like a good place sence people are talking about test pipes.

 

franman, how does this affect the sound of the exhaust?

 

no way a relatively stock KA24DE would put out that much extra HP just by going straightpipe LOL

 

12-15 HP does seem like a lot. Maybe when people remove them, they are already half gone, and thats why it feels like it adds so much more. I used to drive a 5.0L and when i bought it they were bad, removing them and driving the car! WOW. It felt like a brand new car.. and my mechanic that did the work said there was at least 20hp gain, but i was sitting below stock hp though.

BUT I was talking to a guy that does custom exhausts in my area. He said that from the exhaust mani back it would be nice to turn 2.5" remove resonator and replace with a decent cherry bomb, then rmeove the cat and leave with regular piping to whatever muffler my little heart desired.. Said it removes raspy tones, keeps some low end torque, and will not sound ricey at all. ANyone agree with this guy?

 

It's not like it matters since you can't really feel any hp gains unless they are over 20+

 

do you guys believe me now? this guy makes test pipes and knows the gains. i said 12-15 he said 5-15.

still think i don't know what i'm talking about?

 

have u striaght piped ur altima waynehead?