Cat/Muffler Question - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

sin0186 · 10-29-2014, 04:28 PM

I'm trying to figure out if I get a CAT at 3" inlet and 2.5" outlet to 2.5" muffler, would that be "depriving" the SR? I read that the 3" muffler would be the best for SRs and it would create less back pressure. Or would it be ok for me to go 3" inlet to 2.5" outlet to 2.5" muffler?

Thanks!

Swerve240 · 10-29-2014, 08:41 PM

When i bought my S13 the guy had it setup that exact way with the silencer on. It also had a custom catalytic converter welded on the exhaust. It ran like crap and idled high. You could feel the back pressure and surge. I ripped that stuff off the next week and replaced it with a 3" catback exaust all the way. No catalytic converter. My SR now idles perfect around 800 rpms and a lot more responsive. I'd go with the 3" all the way if i were you. It made mine run a hell of a lot better and sounds beautiful.

angel mkiv · 10-29-2014, 09:58 PM

That will work but why wouldn't you want the most out of your sr20 and get a 3" full exhaust?

10-29-2014, 04:28 PM	#1
sin0186 Join Date: Nov 2008 Location: Portland OR Posts: 15 Trader Rating: (0) Feedback Score: 0 reviews	Cat/Muffler Question I'm trying to figure out if I get a CAT at 3" inlet and 2.5" outlet to 2.5" muffler, would that be "depriving" the SR? I read that the 3" muffler would be the best for SRs and it would create less back pressure. Or would it be ok for me to go 3" inlet to 2.5" outlet to 2.5" muffler? Thanks!

10-29-2014, 09:58 PM	#3
angel mkiv Zilvia Addict Join Date: Sep 2009 Location: Seattle, wa Posts: 725 Trader Rating: (4) Feedback Score: 4 reviews	That will work but why wouldn't you want the most out of your sr20 and get a 3" full exhaust? __________________ Instagram username:angelmkiv

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10-29-2014, 08:41 PM	#2
Swerve240 Join Date: Oct 2014 Location: Osaka, Japan Age: 39 Posts: 16 Trader Rating: (0) Feedback Score: 0 reviews	When i bought my S13 the guy had it setup that exact way with the silencer on. It also had a custom catalytic converter welded on the exhaust. It ran like crap and idled high. You could feel the back pressure and surge. I ripped that stuff off the next week and replaced it with a 3" catback exaust all the way. No catalytic converter. My SR now idles perfect around 800 rpms and a lot more responsive. I'd go with the 3" all the way if i were you. It made mine run a hell of a lot better and sounds beautiful.