Just a question, on a SP SE 13B engine, what do you guys think is better a 2.5” or 3” complete exhaust system? If is a 2.5” the materials are easy to find. But if it is 3”, can I find online a 3” output header + 3” pre-silencers + 3” cat + 3” piping + 3” muffler. I don’t want the car too loud. Any idea or suggestion is appreciated.

Thank you,

Luism12lm

 

3" can be loud, i know because mine is loud. isc has a nice 3" setup but it but it is a bolt on setup

 

3" is really for turbo's. I mean the HP gain from 2.5" to 3" wont be worth the extra money

 

unless you're going on a track most of the time, 3-inches is too much for the street with no real-world gain. it's just noise on an streetport engine. if you had a race-type port, maybe, but you're not getting that.

 

Where are you collecting the headers? If it's going to be a short primary system, I would probably use 2" myself, or possibly 2.25". The 2" primary header pipes can collect into a single 2" pipe because the exhaust pulses are phased 180 degrees apart. Racing beat says they have seen very little benefit from increasing the stock pipe diameter in a short-primary system.

A long primary system may benefit from a slightly increased pipe diameter after the collector, I don't know. I do know the RB long-primary exhaust system collects into a larger (2.5"?) pipe just before the muffler.

 

Stick with the 2-1/2". You don't need 3" until you go with an upgraded turbo. Exhaust note will be more manageable with 2-1/2 also.