SilviaLuvr wrote:Well thinks for the correction i just thought that whenever you are dealing with anything that deals with air flow or the flow of an exhaust for that matter then you will need to adjust everything accordenly...ie custom exhaust...i thought that it was all the same...and what difference does it make if it's an N/A or not???
Well, in theory that is right. But with the KA engine, the throttle body is already larger than the intake pipe. The factory intake has several restrictive bends, and it narrows as it spans the radiator. When you replace the factory pipe with a larger, straighter, less restrictive pipe then you open up the airflow. But on THIS engine, the TB is already larger than the intake.... so it is not going to be restrictive at all. With a 1.8l Honda that has a 2" TB, then yes...you would be right, it should be upgraded.
Now in regard to it being N/A or boosted:
On an N/A KA... there will never be enough airflow through the intake to require an upgrade. This is simply because you are 'sucking' air through it. It is more than adequate. Once you start forcing air (boosting) through the TB, then it stands to reason that it could benefit from an upgrade.
As for the exhaust:
N/A or boosted makes a HUGE difference in the diameter of pipes you should use. If you throw 3" pipes all the way from the header to the muffler on an N/A 4cyl, you will lose gobs of torque. Some chaulk this up to back pressure.... it is a result of turbulence and the loss of scavenger effect and vaccum. (somethig like that anyway)
In the end, you should build everything to match. The theory of a 'chain is only as strong as its weakest link' applies. But I assure you, that weakest link isn't the TB.
