Project Silvia Staight Pipe install story

[SHiFT]

Well I got my straight pipe from project silvia earlier today. Quick shipment and great quality. I have a n/a 97 240 5spd with cone filter/ApexI N1 Single Exhaust. I was under the impression that the piece between the header and exhaust was a catalytic converter cause people mentioned that our cars have 2 cats. Well, after I jacked up the car I got the 4 bolts off so the "cat" just fell on the ground (removing rusted bolts = pain in the ***), I looked in there and the damn thing was hollow. Its just a resonator. I later researched the forums that some 240s have 2 cats and some are just resonators. I was pissed, but its my fault for not researching. I drove down the road even though I had a small exhaust leak and didn't really notice any dif, maybe a tinch more torque. It was quieter and higher pitched than the stock piece. Do you guys think this would make a difference at all in terms of wheel hp? I'm going to turbo the car eventually, would this be worth keeping on there or should I just put the resonator back on? Sorry this is so long..

[Silvia007]

What size pipe?? 2.5 inch is max you would want to go on a NA car. 3 inch for turbo applications. As for wheel hp... I think some 91 exhuast cams would be a great mix with that straight pipe.

[p00t]

umm... isnt the purpose of a straight pipe to take place of the cat? if its not doing that theres no point.... theres spots for 2 cats on the 240sx.... find the one with the cat actually in it. and put it there, unless it wont fit?

[SHiFT]

the flanges are 2.5 but the piping is 3" and yes I know thats for turbo but I will have that in the future so I want to get everything only once. Yeah turns out I only have 1 cat, if I want to replace it I'll have to get a header, which I don't think I'll be doing, I don't know yet though. I'm going to be taking it off and maybe (if it fits) take a 2.5 inch pipe and stick it through the resonator so it'll be more straight through.