Exhaust Loudness List
(last update: June 12th, 2008)
Sorry for my lack of updating the list lately. I've temporary moved to the States, stored my car (carcoon) and I unintenionally switched off the automatic messaging functionality for this post. I've turned it back on so you can still count on me.
Please find beneath a list of exhaust loudnesses, compiled by members of SXOC.
The loudnesses presented here are indicative for how load exhausts can be on a Nissan Silvia 200sx (s14/s13). This loudness depends highly on the parts used in the exhaust system. Diameters, turbo pressure, decat, silencer and the rpms that the loudness is measured at do all influence the measured loudness.
Nevertheless I think, as I haven't found a similar list anywhere else, that this list is good to have as a reference.
On a personal note, I'd like to thank everyones input. This list is made by us, for all of us Nissan 200sx drivers that are looking into changing their setup or to compare their results, so please keep on posting your measurements. If you happen to find a mistake. Let me know and I'll correct it.
From loudest to softest exhaust
GP Sports Spec R
Wise Sports Besiege Titanium - 121 db(A)@4000rpm (full decat, without silencer)
Blitz NÜR Spec R (and spec V) - 118 db(A)@4250rpm (with hks downpipe& 3"decat, no silencers)
Motoria - 111db (3" turbo back, backbox silencer only)
Buddy Club Spec III
Megan Racing - 112 db@wot (full decat, without silencer)
Apex - 110 db (Apex single box sytem, xspower 3"downpipe, 5" hollow de-cat, normal cast manifold)
Invidia G200
Buddy Club Pro Spec
Motoria - 108 dB(A) (with apex silenced downpipe)
Tanabe Super Medalion Hyper
Apex s/s - 108 db (3" single Box c/w s/s manifold, s/s elbow, 3" s/s downpipe and 3" s/s Decat)
Wise Sports Besiege
Blitz NÜR Spec - 106 dB(A) (with 2.75" downpipe)
Blitz NÜR Spec R (and spec V) - 104 dB(A)@4500rpm (with bung in, 3" apex front pipe & 3" decat pipe)
Blitz NÜR Spec R - 104 dB(A)@4500rpm (without bung, 2.5" front pipe with jetex small round straight through box)
HKS HiPower 409 - 103 db(A)
Buddy Club Spec II - 102db(A)@4500rpm
Motoria Turboback - 102 db(A)
A'PEXi N1 Dual - 102db @4500rpm (SR, full decat, without silencer)
A'PEXi Bomber 2 - 101 dB(A)
Mongoose 2 - 100 db(A)@4000rpm (3" front pipe, decat silencer, 3" catback)
Apex Single box system - 100 db(A)
A'PEXi GT - 99 db(A)@4500rpm
HKS Hi-Power - 99 db@4500rpm (2.5" front pipe with jetex small round straight through box)
5Zigen Miracle Fireball
A'PEXi N1 Evolution - 98 dB(A)
Fujitsubo Power Getter - 98 dB(A)@4500rpm
Apex Twin Box - 98 dB(A)
A'PEXi N1 ExTi
HKS Dual Dragger - 96 dB(A) (with decat)
Scorpion Suzuka - 96 db(A) (with decat silencer & scorpion 2.7" downpipe)
Apexi GT spec - 95 db@4500rpm (TD06 manifold and front pipe, Scorpian decat silencer)
Tanabe Super Medalion R - <95 dB(A)
PTS custom back box - 97 db(A) (replaces rear Nur spec section)
Apex type 1 - 94 db (3" cat-back system, standard frontpipe and cat)
Tanabe Concept G - <93 dB(A)
OBX TYPE-DTM - 92/94 dB(A)
GP Sports Spec D Pro 2.5" Cat back System with 3" decat - 92db@4500 rpm
A'PEXi HM Evolution - 92db(A)
Apex/Blueflame Sensible Twin Exit - 92db(A)@4500rpm (3" bore, twin 3.5" exit)
HKS Silent Hi-power - 92 db (with full decat and turbo back piping)
Megan Racing?
JIC Bullet 505Ti
Buddy Club Spec IV
Blitz Realize TT
GReddy Evo TT
Fujitsubo Powergetter
Fujitsubo Legalis Super R - 91 dB(A)@4500rpm
A'PEXi N1 Dual - 90 db(A)@4500rpm (with decat frontpipe & scorpion decat silencer)
Fujitsubo RM01A
Motoria catback (without downpipe) - 89 db(A)
XS Power - 89db@4500rpm (ss manifold, elbo, downpipe and cat back welded in custom center and rear boxes)
Apex Gen 2 - 86 db(A)@6500rpm (with bung & decat silencer)
HKS Silent Hi-power - 86 db(A)@4500rpm (full decat)
Mongoose - 85 db@5200rpm (3", de-catted with twin outlet, std manifold and elbow)
OBX Racing Sports Type Hiroshima (Type-H)
RS*R Ex-Mag
GReddy SP2
5Zigen ProRacer
STOCK Exhaust - 82db(A)@4500rpm
5Zigen Fire
If not indicated, all measurements are without silencers and/or ecv's.
How to measure the loudness:
source: somebody at austinburg.com
I hope the picture will stay on that webspace, else it'll be lost in this thread
The Engine RPM needs to be held steady at 75% of rated peak horsepower RPM.
Some other info:
The perception of the loudness of the exhaust sound is dependent on the tone of the sound. That's why
(thanks Matt+ or - one decibel is approximately the smallest sound pressure change the average person can detect.
+ or - 10 dB is approximately the sound pressure change that the average person would associate with twice or half the "loudness".).
on average a regular silencer silences exhaust noise by 7 dB
an enlarged downpipe/frontpipe adds about 2-3 dB:unsure:
Regulations (legal loudnesses):
UK: legal limit: no louder than standard exhaust loudness (maximum of 84 dB)
@Bedford Autodrome: <101 dB(A) from 50 cm away at 75% of max rpm and <87dB(A) from 20 meters away
@Castle Coombe: <106 dB(A) (yr.2004)
Netherlands: legal limit: standard+4dB (maximum of 90 dB)
Germany: legal limit: 95 dB@4000-5000rpm @1m distance (98 dB for youngtimer)
Belgium: legal limit: no louder than standard exhaust loudness (maximum of 84 dB)
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is the GP Sports Spec R. It makes a Nur Spec seam a bit tame 
Originally Posted by sroberts
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