Risk of losing more instead of gaining more...

[Enslaved]

Save ur money and buy another car that's manual and has power from the fctory like a sgti or putra or civic si...then u will gain more satisfaction from modding those cars : )

 

[SkYwAlKeR]

yah yah... get honda or toyota.... proton, better dont la.... later regret....

 

[PocketRocket]

my extractor is still stock 4-1...for top end...if wanna have low to mid torque is better if i change to 4-2-1 rite..? powerzone seems overated...how is hotbits?any other?
im driving a 1.5 manual...

 

[TitanRev]

My Theory

Well, i have noticed the current Toyota vehicles has a special exhaust setup for most of their AT cars.

Take example Camry 2.4
What they do is the piping dia. after the header is large (eg.3.5") then the piping dia. after the CAT is smaller (eg. 3") and the piping dia. after the center bullet is even smaller(eg. 2") straight to the rear muffler.

The theory that i get from what i see is that. They made the dia. after the header large is to allow the exhaust gas to exit the combustion chamber fast and the exhaust gas at this area is the hottest and the flow speed of the gas is the fastest.

Then after the CAT the piping dia. become smaller and smaller this is because exhaust gas give up their heat to the cooler surrounding (the atmosphere) when exhaust gas losses their heat, they losses their flow speed so to ensure a minimun drop in heat and flow speed the engineers shrink the piping dia. section by section. This forces the exhaust gas to be compress on each other thus increases the exhaust heat temp and increases the flow speed. This also creates a slight vacuum inside the exhaust system that helps pull all exhaust gas out from the combustion chamber asap.

The result they get is, a faster flowing of exhaust gas will give better and more powerful combustion as very less exhaust gas is left inside the combustion chamber.

Well, this is my theory lah but don't know to what extent it is correct. Its a good discussion though.

 

[Enslaved]

In a way you could be correct but those cars are tuned for economy not power. Most articles written on exhaust flow and tuning are quite the opposite really, increase in diameter over sections AFTER the header, helps prevent backflow into the engine and thus making the engine work harder to push exhaust gases out. Less backpressure is good, don't be fooled into thinking back-pressure increases torque - i have never read an article which proves this is true : )

The idea is always to move exhaust gases out as fast as possible and backpressure is a definite power robber.

 

[LemonRuski]

i've read the advise that you all have given me.
Looks like, muffler i will keep to the original one.
Might go for bullet and mid box modification.

Piping size wise, i'll keep to the original.

Is that right??