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the silencer on the xforce barely does anything

i tested it on and off, and i couldnt feel a difference

takes the edge off the noise though. and it would depend on how much power you have as to how much power it takes off. someone pushing 350-400hp would notice a bigger loss than someone on a stock turbo at stock boost.

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hrmm, so if epa tests an xforce muffler with the silencer and it passes, would this be the valid reading? or would they have to test the exhaust without the silencer?

I was going through some of the regulations in relation to testing procedures and here's what i found:

PROTECTION OF THE ENVIRONMENT OPERATIONS (NOISE CONTROL) REGULATION 2000 - SCHEDULE 2 - Testing Procedures

5 Vehicle operation and noise measurement

(b) If the Engine Speed at Maximum Power (ESMP) for that engine has not been determined by the EPA—the engine is to be brought to and stabilised at a speed as close as the authorised officer can achieve to one of the following speeds:

(i) if the engine has 5 cylinders or less—4000 rpm,

(ii) if the engine has 6 cylinders—3200 rpm,

(iii) if the engine has 8 cylinders—3300 rpm,

(iv) if the engine has more than 8 cylinders—4300 rpm,

(v) if the engine is a rotary engine—4500 rpm.

© If, in the opinion of the authorised officer, the test speed determined by reference to paragraphs (a) and (b) is not attainable by the engine—the engine is to be brought to and stabilised at the maximum speed that the authorised officer believes that the engine can be safely tested.

Hi guys,

It seems the Apexi bomber exhaust has a dB reading of 98. The N1 has a reading of 94! The fujitsubo legalis R has a reading of 94db (@5100 rpm), while the fujitsubo STD exhaust has 92dB (@5100 rpm).

My question now is, will this level reduce once the BATMBL dump/front pip and large cat is installed? The Apexi cat back (bomber or N1) was what i was looking at - but the sound levels seem to be in the illegal range. I know that the different type of mufflers matters to reduce the sound. Any types that you guys recommend?

Thanks in advance.

Hi guys,

It seems the Apexi bomber exhaust has a dB reading of 98. The N1 has a reading of 94! The fujitsubo legalis R has a reading of 94db (@5100 rpm), while the fujitsubo STD exhaust has 92dB (@5100 rpm).

My question now is, will this level reduce once the BATMBL dump/front pip and large cat is installed? The Apexi cat back (bomber or N1) was what i was looking at - but the sound levels seem to be in the illegal range. I know that the different type of mufflers matters to reduce the sound. Any types that you guys recommend?

Thanks in advance.

if you want legal, you should buy my cat back :P

tanabe 3" mild steel, oval muffler (JASMA approved :O)

see sig.

Trust PE2 specs from what I remember shows 90dB. But I'll assume this changes once you put an aftermarket dump/front pipe in with a high flow cat.

From my experience the PE2 is quite quiet compared to other brands of catbacks. Having said that it still shows the nice RB groal when you hammer it :P

ey guyz i just got home from work (im a mechanic)....and i finished fitting my X-force 3inch turbo back on my 32...the exhaust cost me 950 from just jap....i actually thought that it would be much louder...at idle its a little bit louder than the stock one...i jumped inside and gave it a rev....when you get higher in the rev range thats wen it starts to become loud...i havent driven it yet tho i will first thing tomorow....but the xforce i found is really quiet at idle

hrmm, so if epa tests an xforce muffler with the silencer and it passes, would this be the valid reading? or would they have to test the exhaust without the silencer?

I was going through some of the regulations in relation to testing procedures and here's what i found:

PROTECTION OF THE ENVIRONMENT OPERATIONS (NOISE CONTROL) REGULATION 2000 - SCHEDULE 2 - Testing Procedures

5 Vehicle operation and noise measurement

(b) If the Engine Speed at Maximum Power (ESMP) for that engine has not been determined by the EPA—the engine is to be brought to and stabilised at a speed as close as the authorised officer can achieve to one of the following speeds:

(i) if the engine has 5 cylinders or less—4000 rpm,

(ii) if the engine has 6 cylinders—3200 rpm,

(iii) if the engine has 8 cylinders—3300 rpm,

(iv) if the engine has more than 8 cylinders—4300 rpm,

(v) if the engine is a rotary engine—4500 rpm.

© If, in the opinion of the authorised officer, the test speed determined by reference to paragraphs (a) and (b) is not attainable by the engine—the engine is to be brought to and stabilised at the maximum speed that the authorised officer believes that the engine can be safely tested.

And as you said, old stuff...

The are old regulations.

RB25 is 4800rpm

RB26 is 5200rpm

RB20 (i think) is 4500 or 4400rpm

The above supplied is the old regulations that were changed some 18months ago for Vic and are now motor specific, not generalistic

cheers

I heard the testing in brissy is that they check the dB rating at 2/3 of yer maximum rpm? Well i've used a HKS super drager on my previous r33 gts-t and i liked it, never had problems with the cops at all..its pretty silent at low revs but opens up real hard on high revs...I feel the exhausts all give about the same power gain, but its the exhaust notes that differ between japanese catbacks and xforce, and perhaps durability is of another issue..the japanese exhausts seem to keep that same sweet note fer a long time, but other dodgy exhausts kindda give out a different note after a while compared to when its new...but well just my personal opinion..i would stick with japanese exhausts~ :)

Now im running a fully customised 3.5" exhaust system from japan on my gtr, mines stainless dumps, titanium split front pipes, 3.5" metalcat ( the flow on the metal cat surprises me, i practically feel not much difference comparing it to when i was running straight-thru), 3.5" stainless custom welded catback, it flows awesome but its quite loud cuz im running internals as well, but i did test using a silencer on it, brought the dB down by 3dB, but pretty restrictive....Here's how it sounds~

http://www.grouper.com/GlobalMedia/MediaDe...st=-1&s=7&q=gtr

And as you said, old stuff...

The are old regulations.

RB25 is 4800rpm

RB26 is 5200rpm

RB20 (i think) is 4500 or 4400rpm

The above supplied is the old regulations that were changed some 18months ago for Vic and are now motor specific, not generalistic

cheers

Can anyone shed light to the current regulations in NSW in relation to what the RPM RB25's are tested?

I heard the testing in brissy is that they check the dB rating at 2/3 of yer maximum rpm? Well i've used a HKS super drager on my previous r33 gts-t and i liked it, never had problems with the cops at all..its pretty silent at low revs but opens up real hard on high revs..

Awesome ey! :)

I love my super drager!

  • 1 month later...
  • 2 months later...
Thought i'd bump this one - Emsta - noticed you've ended up getting a PEII.. how's it sound.. what else did everyone else end up doing..

My trip to america has prevented me getting a new exhaust :D

Sorry about resurrecting an old thread, was just doing some reading while having a cup of dilmah tea (supposedly the finest ceylon tea)

Couldnt be happier Links - I still have to slap the car on the dyno, will do that next service. But yeah, batmbls products and the trust cat, is fantastic. Its very quiet too, like, as I mentioned above, I liked the growl of the x-force, but the PE2, is very quiet, goes well when Im building up my car in terms of performance. Basically, got RE Customs to install it, and it was a straight bolt on job - the only trouble was a couple of the bolts that were hard to remove it seems.

In time, will get more mods done. Right now, I need a job :D

Edited by emsta2003

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