If u wan, den i can go vf u 2 da shop.....get discount maa...

Is That Correct?

Ur Car Only Can Open Pod Or Drop In Filter?

Either One? Izzt?

What r u waiting for motherker...faster go dyno

sure, after tuning...haha.......

4-2-1 vs 4-1 header

some article

Very useful link although too techie to be understand by some people....

Link added to the 1st page

how about removing the cat? any noticeable improvement? any recomended piping diameter based on cc? like 1.6, 1.8 and 2.0?

The cat is the most restrictive part in the exhaust system. There will be some minor significant improvement by removing it.

but after removing it, what are the downsides to it? increased FC and noise?

it depends

if you have O2 sensor on/after the cat, probably you'll end up with slightly richer air/fuel ratio.

as for noise, as far as i could remember it doesn't affect the exhaust noise at all.

Some personal experience I want to share.

For those using DOHC VTEC B16 or any other twin cam engines (N/A), manual (assuming you havent done any heavy mods to the engine).

If you want low rpm to mid power (probably balanced power, vtec engagement can also be felt) and no noisy exhaust set up, try using 2 inches (inlet should be around 1.91-1.95 inches) exhaust pipe. You can use the cat converter or not is up to you but I recommend using it to protect the environment.

Use a center bullet (get those better ones like stainless steel). After that, use a S-Flow muffler. For the S-flow muffler any brand can be used even if it's cap ayam. Just find the one with the right inlet.
I have done this setup and all I can say is it produces only bassy sound when revved. During idle, silent and very little bass.

Perfomance wise, I get good pickup at lower rpm to mid rpm. Even during higher rpm there is no lost in power. Overall it's a balance setup for me.

This is just my personal experience and I just hope those using this setup will be happy like I did.

Good article talk about Exhaust Theory and Design

link added to the list

i must say after reading thru all the six pages ..my knowledge on extractor to muffler going good.....
be logging to this forum ... i did a basic mod on my exhuast
i change to 4-1 . remove the cat , change bullet , 2'' piping n pro 1 racing muffler as the shop owner say it for vios only....
my target is to get low end n top speed and good FC...am i doing the right mod....

you aiming for low end, isn't it 4-2-1 being better??
4-2-1 even gives good top speed

I am currently driving an Iswara and am planning to change to 4-2-1 extractor + 1.6 piping + N1 type muffler. What do you guys think?

Not gonna include bullet. Is it gonna be really noisy like some ah beng car? Maybe using the S-flow muffler will help reduce noise right? Iswaradont have cat-converter installed in them right?

Iswara don't have cat (according one of our member).

If you're thinking of running without any extra bullets or silencers, a good S-flow type muffler will be very helpful in reducing the noise. Running loud car is not a good idea, especially when you have just an ordinary engine. It is annoying and does not prove anything.

yeah...will definately choose a good s-flow muffler to reduce the noise.
thanks for the info.

for iswara with stock condition ,i would say 4-2-1 head->1.6piping->sflow muffler and i prefer following the original route for the piping.

I juz changed to s-flow muffler n the sound is damn loud. Is't adding or changing the center bullet/buller silencer wont help much in reducing the exhaust noise??? how many %??? 30% reduce noise??? thanks!