Has anyone with an SR and 3" exhaust used a 2.5" muffler? - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

dwadia · 05-16-2008, 04:13 PM

I'd like to quiet my car down. It's an s14 SR with no major mods, currently at stock boost but i will be setting it to 10psi for daily driving and 12 as a high setting, with an occasional 14psi. Currently it has 3" piping all the way, with a hi-flow cat (which i believe flows the same if not more than 2.5" straight piping would) and no other obstructions. The rear "muffler" is a 3" straight-through resonator.

Have any of you guys installed a 2.5" muffler on your otherwise 3" exhaust systems? If so, what boost where you running and how did it affect the flow? Did you notice a major loss of top-end power? Any other drawbacks?

The specific muffler i'm considering is a Dynomax super turbo. From what i can tell, the inner part of it makes the exhaust flow in a smoothly bent S-shape. Any insight would be appreciated.

*brndck* · 05-16-2008, 04:19 PM

i can't see why you'd put a 2.5" restriction in, instead of just getting a 3" muffler. go get a magnaflow 3" or something similar.

Silverbullet · 05-16-2008, 05:37 PM

you can feel the difference.

have you thought about getting an electronic cut out? It sounds like that is what your looking for.

g6civcx · 05-16-2008, 06:24 PM

Okay, I had an S13 SR. I went from an RS*R ExMag to OEM catback. The car was really laggy and felt like it lost a bunch of power. I never dynoed it on the SR so I don't know how much.

On my V8, going from OEM catback to open exhaust = +60bhp gain! I have dyno sheets to prove it.

Now most aftermarket exhaust won't be as restrictive as the OEM, even if you run 2.5" muffler, but that's a rough estimate for you.

dwadia · 05-16-2008, 06:48 PM

Well my only reason for considering a 2.5" muffler is because from what i understand there is quite a difference in sound level under hard acceleration or WOT (although not much different at idle). I asked Dynomax's tech guys and they said if the size of the muffler is the same and all other things equal, it's a 7-10 db difference, pretty significant i think. They weren't familiar with the SR though, and couldn't tell me much about how it would affect power.

Now i don't want to kill my power too much and this is my main concern. I thought about a cutout, but i really want something i can just live with all the time. Doesn't need to be stock silent. A cutout basically gives me 2 extremes, neither of which i really want.

By putting that 2.5" restriction in the muffler, is the effect essentially the same as having an entire 2.5" exhaust system? Has anyone had 2.5" in ANY part of their system?

JDM_SPORT · 05-16-2008, 06:51 PM

I have a 3 in. down pipe and my catback is a 2.5 with no cat and a resonator and its really quiet.

UNISA JECS · 05-16-2008, 06:53 PM

Maybe you should consider adding a hooker aero muffler chamber, i've heard these tame teh exhaust noise a good bit.

http://www.muffler-pros.com/hoaechmu.html

UNISA JECS · 05-16-2008, 07:00 PM

Heres a good read on exhaust.

http://www.nsxprime.com/FAQ/Miscella...austtheory.htm

koukimonster139 · 05-16-2008, 07:16 PM

maybe you should consider a stock exhaust

if its not loud as shit, its not worth a shit

Jgrand03 · 05-16-2008, 07:18 PM

just get a blitz realize tt (what i have and its quiet as stock when crusing but u can hear it when you get on it)

other options are

circut sport and the old rsr exmag

dwadia · 05-16-2008, 07:33 PM

JDM Sport, how much boost do you run? Are you happy with your set-up?

Unisa Jecs that was a good article, thanks.

boogerlovers · 05-16-2008, 07:36 PM

order a BRM exhaust with a resonator on it...thats what i have on my car...and its really queit...

Def · 05-16-2008, 08:15 PM

Quote:

Originally Posted by UNISA JECS

Heres a good read on exhaust.

http://www.nsxprime.com/FAQ/Miscella...austtheory.htm

Whoever wrote that doesn't know crap. Their only exposure to fluid dynamics is high school physics and chemistry based on what they wrote. There's at least one glaring technical error in every paragraph - do not listen to that crap.

SR2Zero · 05-16-2008, 08:32 PM

Quote:

Originally Posted by Jgrand03

just get a blitz realize tt (what i have and its quiet as stock when crusing but u can hear it when you get on it)

other options are

circut sport and the old rsr exmag

^^ This man speaks the truth!

*njd07* · 05-16-2008, 09:13 PM

Quote:

Originally Posted by Jgrand03

just get a blitz realize tt (what i have and its quiet as stock when crusing but u can hear it when you get on it)

other options are

circut sport and the old rsr exmag

werd!!! I have the realize tt....I love it...so quiet when cruising/idling but sounds like a beast when I get on it. best exhaust ever. buy this exhuast if you want something quiet!!!!!

98koukile · 05-17-2008, 08:57 AM

Depending on your power it shouldn't matter 2.5 to 3". There are people that have dyno proven more power 2.5" axle back with the rest of the system being 3" but they were sub 230hp at the wheels

drkidd22 · 05-17-2008, 09:27 AM

I did my exhaust last week, downpipe is 3in connected to a straight 3in pipe, no cat, no resonator no nothing back to a magnaflow with a 2.5 in/4in out.

Sound is pretty decent, nothing exagerated and about power can't tell much cuz I still have to tune. The guys at the custom exhaust shop did recomend me to get a 3in/out muffler though.

DohcKA · 05-17-2008, 09:42 AM

go get a vibrant exhaust... simple sleeper look....

05-16-2008, 04:13 PM	#1
dwadia Zilvia Junkie Join Date: Sep 2006 Location: NJ Age: 42 Posts: 302 Trader Rating: (2) Feedback Score: 2 reviews	Has anyone with an SR and 3" exhaust used a 2.5" muffler? I'd like to quiet my car down. It's an s14 SR with no major mods, currently at stock boost but i will be setting it to 10psi for daily driving and 12 as a high setting, with an occasional 14psi. Currently it has 3" piping all the way, with a hi-flow cat (which i believe flows the same if not more than 2.5" straight piping would) and no other obstructions. The rear "muffler" is a 3" straight-through resonator. Have any of you guys installed a 2.5" muffler on your otherwise 3" exhaust systems? If so, what boost where you running and how did it affect the flow? Did you notice a major loss of top-end power? Any other drawbacks? The specific muffler i'm considering is a Dynomax super turbo. From what i can tell, the inner part of it makes the exhaust flow in a smoothly bent S-shape. Any insight would be appreciated.

05-16-2008, 06:53 PM	#7
UNISA JECS Nissanaholic! Join Date: Feb 2007 Location: Socal Fontana Age: 46 Posts: 2,380 Trader Rating: (40) Feedback Score: 40 reviews	Maybe you should consider adding a hooker aero muffler chamber, i've heard these tame teh exhaust noise a good bit. http://www.muffler-pros.com/hoaechmu.html __________________ PARTS 4 SALE !! Z32 E-Brake/Parking Brake Heatshield Assemblys!!! *Rep/Feedbacks*

05-16-2008, 07:00 PM	#8
UNISA JECS Nissanaholic! Join Date: Feb 2007 Location: Socal Fontana Age: 46 Posts: 2,380 Trader Rating: (40) Feedback Score: 40 reviews	Heres a good read on exhaust. http://www.nsxprime.com/FAQ/Miscella...austtheory.htm __________________ PARTS 4 SALE !! Z32 E-Brake/Parking Brake Heatshield Assemblys!!! *Rep/Feedbacks*

05-16-2008, 07:16 PM	#9
koukimonster139 Zilvia FREAK! Join Date: Jan 2006 Location: Birmingham, AL Age: 38 Posts: 1,379 Trader Rating: (0) Feedback Score: 0 reviews	maybe you should consider a stock exhaust if its not loud as shit, its not worth a shit __________________ ho ha ho chi chi

05-16-2008, 07:36 PM	#12
boogerlovers Zilvia FREAK! Join Date: Jun 2007 Location: Palmdale Age: 37 Posts: 1,082 Trader Rating: (8) Feedback Score: 8 reviews	order a BRM exhaust with a resonator on it...thats what i have on my car...and its really queit... __________________

05-16-2008, 06:24 PM	#4
g6civcx Post Whore! Join Date: Apr 2004 Location: Virginia, USA Posts: 5,764 Trader Rating: (5) Feedback Score: 5 reviews	Okay, I had an S13 SR. I went from an RS*R ExMag to OEM catback. The car was really laggy and felt like it lost a bunch of power. I never dynoed it on the SR so I don't know how much. On my V8, going from OEM catback to open exhaust = +60bhp gain! I have dyno sheets to prove it. Now most aftermarket exhaust won't be as restrictive as the OEM, even if you run 2.5" muffler, but that's a rough estimate for you.

05-16-2008, 06:48 PM	#5
dwadia Zilvia Junkie Join Date: Sep 2006 Location: NJ Age: 42 Posts: 302 Trader Rating: (2) Feedback Score: 2 reviews	Well my only reason for considering a 2.5" muffler is because from what i understand there is quite a difference in sound level under hard acceleration or WOT (although not much different at idle). I asked Dynomax's tech guys and they said if the size of the muffler is the same and all other things equal, it's a 7-10 db difference, pretty significant i think. They weren't familiar with the SR though, and couldn't tell me much about how it would affect power. Now i don't want to kill my power too much and this is my main concern. I thought about a cutout, but i really want something i can just live with all the time. Doesn't need to be stock silent. A cutout basically gives me 2 extremes, neither of which i really want. By putting that 2.5" restriction in the muffler, is the effect essentially the same as having an entire 2.5" exhaust system? Has anyone had 2.5" in ANY part of their system?

05-16-2008, 06:51 PM	#6
JDM_SPORT Join Date: Mar 2008 Location: city of idustry Posts: 19 Trader Rating: (0) Feedback Score: 0 reviews	I have a 3 in. down pipe and my catback is a 2.5 with no cat and a resonator and its really quiet.

05-16-2008, 07:18 PM	#10
Jgrand03 Zilvia Junkie Join Date: Jul 2006 Location: Portland Age: 37 Posts: 359 Trader Rating: (2) Rides Gallery: Jgrand03 Feedback Score: 2 reviews	just get a blitz realize tt (what i have and its quiet as stock when crusing but u can hear it when you get on it) other options are circut sport and the old rsr exmag

05-16-2008, 07:33 PM	#11
dwadia Zilvia Junkie Join Date: Sep 2006 Location: NJ Age: 42 Posts: 302 Trader Rating: (2) Feedback Score: 2 reviews	JDM Sport, how much boost do you run? Are you happy with your set-up? Unisa Jecs that was a good article, thanks.

05-17-2008, 08:57 AM	#16
98koukile Zilvia Addict Join Date: Jan 2007 Location: Western Mass Age: 38 Posts: 949 Trader Rating: (3) Feedback Score: 3 reviews	Depending on your power it shouldn't matter 2.5 to 3". There are people that have dyno proven more power 2.5" axle back with the rest of the system being 3" but they were sub 230hp at the wheels __________________ Just talking about cars, one at a time Horsepower sells cars torque wins races -Shelby

05-17-2008, 09:27 AM	#17
drkidd22 BANNED Join Date: Jun 2007 Location: USA Age: 39 Posts: 146 Trader Rating: (0) Feedback Score: 0 reviews	I did my exhaust last week, downpipe is 3in connected to a straight 3in pipe, no cat, no resonator no nothing back to a magnaflow with a 2.5 in/4in out. Sound is pretty decent, nothing exagerated and about power can't tell much cuz I still have to tune. The guys at the custom exhaust shop did recomend me to get a 3in/out muffler though.

05-17-2008, 09:42 AM	#18
DohcKA BANNED Join Date: Jul 2005 Location: NorCal,East Bay Age: 37 Posts: 508 Trader Rating: (0) Feedback Score: 0 reviews	go get a vibrant exhaust... simple sleeper look....