Dealing w/ exhaust drone after installing straight pipe? - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

HorizonX · 05-17-2011, 05:43 PM

Just got an aftermarket exhaust installed on my S14a and I'm getting droning/resonating in the mid 2000 to mid 3000 rpm range that gets progressively worse in each gear; it's *pretty* bad on the highway. Looking for advice on ways to get rid of it... my current plan is to inspect all the hangers/bolts and if no problems are there get a resonator to install somewhere in the midpipe, but it seems resonators w/ 2.5" ID have a *huge* OD and there's not much room down there...

Before: Bone stock but the cat and precat were both gutted long before I got there (just found this out after owning the car for quite some time... kind of a "wtf?!" moment... at least I'm in Kanas =_= ). Muffler inlet had finally rusted through so...

Now: Megan Racing downpipe, custom 2.5" aluminized catback piping, Megan Racing MU-DT muffler. Stock cat left alone (read: still hollow). Muffler is installed straight back, hangers seem pretty solid. (PS: Not that it's important to the problem, but it also has a drop-in K&N air filter from when I first got it, recently cleaned.

)

Any/all advice/knowledge greatly appreciated! Looking for the most cost-effective way to cut down on the noise w/out sacrificing too much of my new flow. Thanks.

n8RPS13 · 05-17-2011, 05:50 PM

Get a new cat! Also once you have some carbon build up it shoud get a bit quiter.

pandaroo · 05-17-2011, 06:04 PM

ya a cat should quiet it down significantly.

HorizonX · 05-18-2011, 05:33 PM

Agree that a new cat would quiet it down but isn't that mostly because it restricts the airflow? The actual exhaust noise I don't have problems with so much, it's just the resonance inside the cabin that drives me crazy. e.g. If I try cruising @ 85mph the noise level is perfectly okay, but at 70mph or so it's unbearable. I'll probably get a cat at some point probably but OE cats are like 300$ and finding a direct fit for a 95-98 240SX is a PITA. >.< Just worried I'd only be reducing the drone proportional to the reduction in overall exhaust volume... in that case even if it got brought back down all the way to stock levels it'd still be pretty damn annoying.

Phate · 05-18-2011, 05:43 PM

I'd buy a huge (long) resonator. Or maybe two. Or just deal with it.

DoobieS13 · 05-18-2011, 06:01 PM

Earplugs ftw

nismoracingsx · 05-18-2011, 06:02 PM

+1 for a resonator, they help quite a bit.

HorizonX · 05-18-2011, 06:36 PM

Does it matter where a resonator goes? (I'm guessing it can go almost anywhere in the catback) I've heard good things about Aero resonators in general but I'm curious as to what other S13/S14 owners have actually put on to deal with this... any suggestions?

PS: earplugs don't sound like such a bad idea while I get this sorted out, actually *lol*

05-17-2011, 05:43 PM	#1
HorizonX Join Date: May 2011 Location: Outer Space Posts: 3 Trader Rating: (0) Feedback Score: 0 reviews	Dealing w/ exhaust drone after installing straight pipe? Just got an aftermarket exhaust installed on my S14a and I'm getting droning/resonating in the mid 2000 to mid 3000 rpm range that gets progressively worse in each gear; it's pretty bad on the highway. Looking for advice on ways to get rid of it... my current plan is to inspect all the hangers/bolts and if no problems are there get a resonator to install somewhere in the midpipe, but it seems resonators w/ 2.5" ID have a huge OD and there's not much room down there... Before: Bone stock but the cat and precat were both gutted long before I got there (just found this out after owning the car for quite some time... kind of a "wtf?!" moment... at least I'm in Kanas =_= ). Muffler inlet had finally rusted through so... Now: Megan Racing downpipe, custom 2.5" aluminized catback piping, Megan Racing MU-DT muffler. Stock cat left alone (read: still hollow). Muffler is installed straight back, hangers seem pretty solid. (PS: Not that it's important to the problem, but it also has a drop-in K&N air filter from when I first got it, recently cleaned. ) Any/all advice/knowledge greatly appreciated! Looking for the most cost-effective way to cut down on the noise w/out sacrificing too much of my new flow. Thanks.

05-17-2011, 05:50 PM	#2
n8RPS13 Zilvia FREAK! Join Date: Sep 2009 Location: New Smyrna Beach Posts: 1,296 Trader Rating: (22) Feedback Score: 22 reviews	Get a new cat! Also once you have some carbon build up it shoud get a bit quiter. __________________ WASTED I AM!

05-17-2011, 06:04 PM	#3
pandaroo Zilvia Member Join Date: Nov 2010 Location: panama city florida Posts: 165 Trader Rating: (1) Feedback Score: 1 reviews	ya a cat should quiet it down significantly. __________________ 89 2tone coupe 2jzgte swap in progress

05-18-2011, 06:02 PM	#7
nismoracingsx Zilvia Addict Join Date: Sep 2007 Location: Alachua, FL Age: 37 Posts: 969 Trader Rating: (32) Feedback Score: 32 reviews	+1 for a resonator, they help quite a bit. __________________

05-18-2011, 05:33 PM	#4
HorizonX Join Date: May 2011 Location: Outer Space Posts: 3 Trader Rating: (0) Feedback Score: 0 reviews	Agree that a new cat would quiet it down but isn't that mostly because it restricts the airflow? The actual exhaust noise I don't have problems with so much, it's just the resonance inside the cabin that drives me crazy. e.g. If I try cruising @ 85mph the noise level is perfectly okay, but at 70mph or so it's unbearable. I'll probably get a cat at some point probably but OE cats are like 300$ and finding a direct fit for a 95-98 240SX is a PITA. >.< Just worried I'd only be reducing the drone proportional to the reduction in overall exhaust volume... in that case even if it got brought back down all the way to stock levels it'd still be pretty damn annoying.

05-18-2011, 06:01 PM	#6
DoobieS13 Zilvia Junkie Join Date: Oct 2010 Location: Delaware Age: 32 Posts: 425 Trader Rating: (0) Feedback Score: 0 reviews	Earplugs ftw

05-18-2011, 06:36 PM	#8
HorizonX Join Date: May 2011 Location: Outer Space Posts: 3 Trader Rating: (0) Feedback Score: 0 reviews	Does it matter where a resonator goes? (I'm guessing it can go almost anywhere in the catback) I've heard good things about Aero resonators in general but I'm curious as to what other S13/S14 owners have actually put on to deal with this... any suggestions? PS: earplugs don't sound like such a bad idea while I get this sorted out, actually lol