anyone to decat my exhaust?

[jacobrjett]

ive been thinking about getting my cat converter removed and replaced with straight pipe to free it up a bit and give it a bit more of an "exhaust tone"

dont want a boyracer sound, I just want to be able to hear it a bit more, the intake is a lot louder then the exhaust on my car, id like to be able to hear both

anyone out there that wants to weld in a piece of straight pipe for a reasonable price? i believe its a 2 1/4 inch exhaust.

i was also told that the mercury in a cat is worth a lot and you can get $70 for a cat at a metal recyclers, so maybe if someone wants that in exhange? or i can just pay like 50 bucks?

[1I1]

FWIW i had the cat removed from my corolla and wish i never bothered, sounded shit / ended up putting another resonator in to get rid of the raspyness

[l SIC l]

I believe now it's completely illegal to de-cat an exhaust? You need certs done for everything you do to them now too.

[jacobrjett]

ah right. cheers

rasp is bad! I just want a nice deep exhaust note coupled with the sound of open trumpets(yea i know trumpets lose power but i dont have to be going as fast as i can to enjoy driving cars like you guys). I have googled this but every opinion I found online seemed to be in the states, and they say "why would you decat its illegal" so I couldnt find any straight answers.

maybe I am better off just replacing the end muffler to find that tone I want. I was looking at the "borla" mufflers, shite they are expensive though. But if I just replace the muffler with a big bore I will have become what I hate!
http://performanceexhaust.co.nz/products-page/other-products/big-bore-muffler-borla%C2%AE-boomer-thumper/

they look like they might be a bit boyracey looking though... i want something that looks standard...

i guess im getting totaly off topic now and will go back to googling.

[Leon]

I believe now it's completely illegal to de-cat an exhaust? You need certs done for everything you do to them now too.

Not correct luckily.

[Shrike]

ah right. cheers

rasp is bad! I just want a nice deep exhaust note coupled with the sound of open trumpets(yea i know trumpets lose power but i dont have to be going as fast as i can to enjoy driving cars like you guys). I have googled this but every opinion I found online seemed to be in the states, and they say "why would you decat its illegal" so I couldnt find any straight answers.

maybe I am better off just replacing the end muffler to find that tone I want. I was looking at the "borla" mufflers, shite they are expensive though. But if I just replace the muffler with a big bore I will have become what I hate!
http://performanceexhaust.co.nz/products-page/other-products/big-bore-muffler-borla%C2%AE-boomer-thumper/

they look like they might be a bit boyracey looking though... i want something that looks standard...

i guess im getting totaly off topic now and will go back to googling.

if you want to hear what a kaimoto exhaust and apexi muffler sound like come over one weekend and you can chuck the one (breifly) I have sitting in the garage on to give you an idea

[l SIC l]

I believe now it's completely illegal to de-cat an exhaust? You need certs done for everything you do to them now too.

Not correct luckily.

When I still had the Supra a few months back I was asking around local exhaust shops about how to make it a little louder (though I just ended up running the turbos parallel to make it sound like a freight train on roids), and the shops were saying since the start of this year you have to have everything certified regarding exhaust modifying and in no way is it legal to remove cats??

[Bling]

Don't do a straight pipe, put in a resonator at least. Or just leave it as is if it's not causing you any problems. Less hassle

[Kiwi-Corolla]

Mine was raspy as hell when I removed my cat, but a couple of resonators soon took care of that.

I took videos as a comparison.

Cat removed + one 8" long resonator:
http://www.youtube.com/watch?v=o2o9rXhy ... ature=plcp

Cat removed + one 8" long and one 10" long resonator:
http://www.youtube.com/watch?v=GnsyrCtI ... ature=plcp

Cat removed + one 10" long and one 18" long resonator:
http://www.youtube.com/watch?v=tlYqiuOb ... ature=plcp

[iOnic]

I believe now it's completely illegal to de-cat an exhaust? You need certs done for everything you do to them now too.

Not correct luckily.

When I still had the Supra a few months back I was asking around local exhaust shops about how to make it a little louder (though I just ended up running the turbos parallel to make it sound like a freight train on roids), and the shops were saying since the start of this year you have to have everything certified regarding exhaust modifying and in no way is it legal to remove cats??

^ They were misinformed.

[Mr Ree]

Yep, another clear case of ill informed people in the trade.

The regulations are on the LVV site for anyone who wants to know the facts.

[Stott69]

All you need to do is replace the squashed peice over the sub frame

[l SIC l]

Oh... dicks.

What's the Legal DB limit these days anyway? Is it 90-93?

[Shrike]

Oh... dicks.
What's the Legal DB limit these days anyway? Is it 90-93?

(a) in the case of a moped (LA or LB‐Class), 91 dBA; or
(b) in the case of a motorcycle with an engine capacity of 125 cc or less (LC,
LD or LE‐Class), 96 dBA; or
(c) in the case of a motorcycle with an engine capacity of more than 125 cc
(LC, LD or LE‐Class), 100 dBA; or
(d) in the case of an MA, MB, MC, MD1, MD2, or NA‐class vehicle that was
manufactured before 1 January 1985, 95 dBA; or
(e) in the case of an MA, MB, MC, MD1, MD2, or NA‐class vehicle that was
manufactured on or after 1 January 1985:
(i) if first registered in New Zealand before 1 June 2008, 95 dBA; or
(ii) if first registered in New Zealand on or after 1 June 2008, 90 dBA.

NOTE 1: The decibel figures specified in 2.9(1) are the figures set by the Government, as specified in Land
Transport Rule: Vehicle Equipment Amendment 2011, and may change from time to time as
Government policy dictates. Such changes will be reflected in an amendment to this low volume
vehicle standard.
NOTE 2: ‘dB’ refers to ‘decibels’, and the ‘A’ denotes ‘A‐weighted decibels’, which is an adjustment process that
takes into account the varying sensitivity of the human ear, to different decibel levels at different
frequencies. Low frequency sounds are quieter to the human ear. The ‘A’ weighting curve primarily
takes into account the 500‐10,000 Hz frequency range.
Decibel factoring for specific situations
2.9(2) A factor of 4 dBA may be subtracted from the average decibel level recorded in
2.8(13), in order to compensate for the increased background noise caused by
the close proximity of the engine to the exhaust outlet, in the case of a low
volume vehicle, other than a motor‐cycle, that has either:
(a) the engine positioned to the rear of the driver; or
(b) the exhaust outlet positioned within 1.5 metres (5 feet) of the engine.
2.9(3) A factor of 2 dBA may be subtracted from the average decibel level recorded in
2.8(13), in the case of a low volume vehicle, other than a motor‐cycle or one that
has the factor specified in 2.9(2) already applied, that incorporates a particular
type of engine, or engine equipment or components, that emits an unusually high
level of mechanical sound, if the low volume vehicle certifier believes that the
exhaust noise emission figure may be influenced by that engine type, equipment,
or components.
LVVTA Low Volume Vehicle Standard 90‐20(03) (Exhaust Noise Emissions) Page 19 of 22
© Low Volume Vehicle Technical Association (Inc.) December 2011
2.9(4) A factor of 5 dBA may be subtracted from the average decibel level recorded in
2.8(13), in the case of a scratch‐built low volume vehicle of scratch‐built subcategory
‘Historic Replica’, or scratch‐built sub‐category ‘Reproduction’, first
registered in New Zealand on or after 1 June 2008, that is a replication or
reproduction of a vehicle manufactured before 1 January 1985.
NOTE 1: An engine type referred to in 2.9(3) is typically a diesel engine or an air‐cooled engine, and the
components or equipment referred to in 2.9(3) may include cooling fans, mechanical belt‐driven
superchargers, gear‐driven camshafts and balance shafts, belt‐driven primary drives, and dry
clutches. In order for such components to have an influence on the exhaust noise emission testing, it
will generally either have no effective shielding surrounding it, or be positioned within two metres (six
feet) of the sound level meter microphone.
NOTE 2: In a case where shielding around the vehicle is used as described in 2.7(3), the decibel factoring noted
in 2.9(2) and 2.9(3) cannot be applied.

http://www.lvvta.org.nz/documents/stand ... ssions.pdf

[l SIC l]

^ Thank you sir