hi guys..since myvi have its catalytic converter hooked up so near after the extractor..how do i change the exhaust system if i wanted to keep back the CAT in the system but just change the piping size by a little,4-2-1 extractor,mid muffler and back muffler to enhance the power/torque and also sound..

have anyone heard of variable exhaust system,is it available in those " exhaust specialist shop " and if i really wanted to change the exhaust,is there any type of shop that can do it professionally except those shop that shows out " exhaust specialist " as their shop name(because it sounds not right,like fake)

i'm confused with the piping measurement. lets say 2.5" piping. the 2.5" is measured from internal diameter or external diameter of the pipe?

I hav a question here, does extractor has life? How long can it last? I saw a 10 years old Mivec extractor selling for rm300, izit an acceptable price? How does this extractor affect my fc? higher or lower?

Becoz I heard people say extractor will increase fc, but my fren change extractor, he claimed that he has much better fc, dunno y...

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Added on December 3, 2007, 11:00 amShould I get a new Powerzone extractor? Or take this RM300 Mivec extractor?

My car is SGTI...

This post has been edited by DaViDcHiN: Dec 3 2007, 11:00 AM

Usually, that refers to the external diameter of the pipe. I'm using 2" pipe, the internal diameter is 1.6" if I'm not mistaken.

I have a question. Certain cars have more than one, or even more than two centre box on their exhaust system. What is the purpose for that? Is it aims to achieve an optimal gas flow? It seems that more expensive cars have more than one center box.

its actually really hard to say if modding the whole complete exos setup will make ur INCREASE FC or Decrease FC.

majority of the time, changing to a bigger diameter exos, bigger piping, extractor, usually WILL give u more power, but in return sacrifice FC.

but on the other hand for me, i change my stock 1.3 piping from extractor till muffler.

i got a way bigger FC n increase in power as well.

as long as the extractor has no dents n crack, seems good to go

David, when you change your exhaust manifold/extractor to a tuned one, the engine volumentric efficiency is increased. With a tuned extractor, an optimum gas flow is generated after the exhaust manifold. So, with engine that run more efficiently, the overall engine can save more fuel consumption, that is in a controlled environment, excluding the driver driving behaviour. That's why, certain people said that after they changed to a tuned extractor, e.g. 4-2-1 design extractor, they can notice an improvement in fuel consumption. That's what I know from my reading through books and automotive websites.

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Added on December 31, 2007, 1:24 pmSleep, swirling or spiral flow muffler/resonator use another method of sound cancellation. Instead of using fiber material for sound insulation, this type of muffler/resonator use spiral flow louver for sound cancellation.
I'm not sure for the effectiveness of the sound cancellation compared to fiber muffler, but according to one of the manufacturer of this type of resonator, Morosso, it "helps speed the exhaust gasses out of the exhaust system to lower the exhaust gas temperatures as quickly as possible". I've never try this type of resonator, but some of people who use this resonator said that they can feel a general improvement in car performance compared to when they are using fiber filled resonator.





This post has been edited by Malvine: Dec 31 2007, 01:24 PM

bro, myvi's catalytic converter is on the extractor. Once change extractor that mean take out the CAT. if u wan to keep the CAT just change piping, bullet and muffler.

I've just changed the extractor and noticed that got sound everytime when accerelated compared to stock extractor, is it normal??

Pardon my noob question,
i went to exhaust modification shop at my hometown, i wanted to change extractor to 4-2-1 since im always travelling on highway to work. but the boss say auto can only use 4-1. izit true?
btw, im using toyota corolla AE111 auto. any good extractor to recommend?

thanks

V88, I think it's normal, because I also experience that when I change to 4-2-1 extractor.

auto is best using 4-2-1... tht boss is screwing u hard

reli ar
damn that guy
go back ask him to change another 1 for me free

guys,i didnt meant to be overthinking here, but i got one question in mind, a car mod noob like me, if go to the exhaust shop and say i want a branded fullset exhaust setup e.g hotbits, how am i know that i'm geting the genuine hotbits but not those other brand of similiar item?

is the hotbits muffler, bullet and extractor all come with the hotbits word engraved on it? or is there any other way to determine?

can somebody englighten me?

This post has been edited by gohlex: Apr 15 2008, 12:37 AM

that depends on what workshop u go to... if u looking for hotbits, go to speedworks...

gohlex, follow what sky said.

h22a stock is 4-1

changing to jasma 4-2-1...wht will be the significant difference..at the moment..stock h22a is alredi damn good..

After reading the entire 20 pages of postings made by members here, could i ask how do we resolve 2 problems that a car owner will encounter when he changed his stock extractor to a tuned performance 4-2-1 type :-

1. Omission of Heat Shield - Without the shield, my existing stock CAI will not be able to draw in hot air during the regular morning start-up and normal cruising. I noticed this would worsen the FC as i had previously experienced before in forgetting to connect the vacuum hose connected to the CAI flap that draws in hot air from the heat shield. Upon realising why my fuel meter needle begun to drop faster then usual, then only i realise the vacuum hose had been disconnected when i service my plugs.

Radiated heat from the exposed upgraded extractor will also be no longer buffered by the heat shield. Would this effect the cooling efficiency of our radiator and causing our engine to run hotter and thereby lowering FC again?

A proposal by a member to heat wrap the extractor was not recommended as it would elevate the operation temp. of the extractor and thereby increased its risk of failure.

2. Increased in Sound - With stock or even with replacement midbox and muffler, members have experienced an increase in sound emission, hence how can we reduce the louder sound to the same original emission level before we replace the extractor?

Really appreciate it if all the sifus in this forum could assist this noobie here on how to resolve my both concerns as i'm very keen to upgrade my stock extractor but hopefully would not cause another problem later.

This post has been edited by alamdamai1: Apr 15 2008, 12:39 PM

too bad i'm in kuching, no speedworks here.
that why i wonder is the item realy genuine if
the shop claim it is hotbits...

This post has been edited by gohlex: Apr 15 2008, 09:12 PM

my friend gen2 auto changed 4-2-1 top speed 170km/h stock become 140km/h.
he so regret, after a while all back to stock

1) bro, custom make a CAI and a heat shield. The radiated heat from the extractor will not effect the cooling efficiency, thats why there is a radiator fan. The only problem if there is no heat shield is the hot air that is sucked by your air filter. Thats all. Be creative on the CAI route/materials. I heard from someone IF u wrap the extractor, in a long term it will crack, but it is better than a heat shield. So, i have no comments on wrapping the extractor.

2) Add in a center bullet. Easy.