[travinh]

Why after market header boost the engine horse powers? Do I need to replace the whole exhaust system to install the header?

Why Toyota does not install a header that boost HP from factory?

Thank you for your lesson.
Cal

 

[Barney_Fife]

wow. um...since all that info is out there on the web u can always google it. i think if we tried to put it all in one thread, we'd crash the system.

 

[asianflava]

The "header" or "headers" because you have 2 in a V8, are the exhaust manifolds. It is the part of the exhaust system that hangs right off the head of the engine. You don't have to remove the entire exhaust system to replace them, but you may as well since you have to disconnect it anyway. You will also have better power gains if you do the whole thing.

Typical manufacturing uses a cast iron exhaust manifold because it is cheaper and more robust than tubular headers.

They increase horsepower because it is less restrictive than the factory exhaust manifold. They can also be tuned (by the manufacturer) to provide more power in different areas of the powerband.

 

[greg hazlett]

Noise emissions as well as CO2 emissions as well...

And I don't agree that you have to replace the entire exhaust system to gain the max from headers..10-15 years ago yes but the exhuast's of today are pretty free flowing...usually replacing the cat back system is for sound or if you prefer the look of duals.

 

[travinh]

Does this mean the car may not pass the smog test once the headers installed?

Noise emissions as well as CO2 emissions as well...

And I don't agree that you have to replace the entire exhaust system to gain the max from headers..10-15 years ago yes but the exhuast's of today are pretty free flowing...usually replacing the cat back system is for sound or if you prefer the look of duals.

 

[asianflava]

Does this mean the car may not pass the smog test once the headers installed?

It depends. If you still have all the emissions equipment i.e. cats, O2 sensors, etc then it shouldn't matter. The problem may be when they do the visual exmaination. Some states will pass it some won't.