Hey there. WHen I got my 95 240sx it was straight piped. I added a high FLow cat from Mangnaflow, but I feel I lost some power. But I'm planning on getting 2 cats of the same brand and style but bolt on. I'll gut 1, while I'll keep the other as it is. I'll get them both bolt on, go to my muffler shop, intall the gutted one, and when Smog testing comes around I'll install the working one. Anyone done or tied this before? Los Angeles sucks for performance man, too many restrictions..

 

You ever think of just using one high-flow cat? You really don't lose much in the way of performance (unless you're running loads of boost, wide open every day on the track). And I mean hardly anything. Not living in Cali, the only thing I can think of is that a high-flow cat won't pass the inspection - does it have to be an original Nissan part? (Can you use Nismo? lol)

Seriously, up here (Ontario) we don't have to have the OEM parts and I see no 'real' benefit to not having a cat except more smog for everyone else.

 

run straight pipe, use the normal cat for smog testing. make sure both have the same flanges, so it will be just a bolt on affair

 

Yep. That's what i'm planning on doing. I have some Greddy Headers 4 to 1 coming in soon. I'll see how big the outlet on the headers is, and i'll match the piping size and cat sizes to it too. thx!

 

High flow cats aren't a bad idea at all, especially with the cats in our cars as old are they are. I was thinking about picking one up.

My 240sx buddies swear up and down a straight pipe will lose you power, I've yet to see it in action though.

Dr.