well i just got my vishnu up pipe and am waiting for my gutted down pipe to arrive. so that leaves me with the third cat in the mid pipe.

would replacing that cat or gutting it offer significant gains? and if i do leave it in, would it keep my exhaust from smoking/smelling (as i noticed in another post that someone had lots of smoke coming out after d/p and u/p install) because i live in california and don't want to get sent to the ref for having a smoky tail pipe.

if it makes a big difference in power, then what the heck, i already got rid of the other two. but if it won't make any real noticable power increases but will keep my car from noticabally/visually polluting then i'll just leave it on.

-tj

thanks

 

I can't really answer the power question, but I've got Helix up and down with a Borla original cat-back. The system rocks, and I don't have any bad smell or smoke from my tailpipe.

 

Well I got a downpipe and a HKS Carbon-Ti exhaust, still have my up pipe right now, and no funky smells or smoke.

 

It won't smoke, but it WILL stink. I went catless briefly just to see if I could squeeze a couple more HP...and it was just louder and stinkier than with a single highflow.

 

If you are still running stock go ahead and leave one cat in the mix. The last one is the least restrictive, and it would probably only free-up 5hp if removed. You would gain more from an axle back or cat-back exhaust. Besides, you can feel good about being somewhat eco-friendly.

 

i have a blitz nur spec installed 5hp isn't worth taking it out i guess. it'll still look stock since the gutted down pipe still has it's heat shields intact, so it'll look stock when Mr policeman goes underneath for a look. and the up pipe is hard to see (im still looking for it). thanks

-tj

 

Kind of like feeling good about smoking filtered cigarettes instead of roll your own? LOL

 

I'd say get a high flow to keep the stick down. Not sure if you will pass CA emissions with just one cat, but it should be easy to just slap the stock downpipe back on.




:banana:

 

definately go catless... you make more power... and it costs less than getting a system with a hi flow cat, and exhaust components other than an uppipe.. are easy to swap out for a smog test...

 

I went from hiflow cat to catless. Definitely stinkier, but the throttle response is much better now.

 

Am I wrong in thinking that a Helix uppipe and down pipe, and Helix cat back system would be a completly catless system? Or is there a cat between the downpipe and the exhaust? I've been searching, but I havent found a definitive answer.

 

Yes, the Helix downpipe replaces both the second and third cats. Coupled with an uppipe, you would be completely catless.