sorry for the long title but i saw this on 2 guy garage a couple months back and this topic came into mind because i always see debates and arguments about back pressure being good or bad. also it explains the difference and purpose of after market headers and exhaust.




on a side not, is there any company that actually makes longer exhaust ported headers for our cars? the ones i always see or similar to the stock exhaust manifolds and after watching this vid i personally think the header portion doesnt do any better performance or benefit other than the Y-pipe freeing up some exhaust flow...

 

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That was a pretty good explanations, makes alot of sense.

 

 

Wow! I liked that. It does make me wonder how headers work now. Though any header is better than stock with a fat cat in it.

 

Header theory can get pretty extensive, and very complicated for some. It is easy to get lost in it all... There is more to longer runners vs short and no back pressure vs some...

In any case, you will never get the exact header/exhaust setup for your car/engine without going for a full custom setup. Most cases this is limited by the space you have to work with in the car.

On a well cammed/ built, VQ35 with proper air flow through the heads and so on, a "proper header" for that setup will be a 1 7/8" stepped up, and a 3" exhaust will easily be too small...

Anyways, flow and high port velocity together makes for a very efficient setup and makes a lot of power.

 

More than you will ever want to know

http://www.thirdgen.org/techboard/ex...-you-ever.html