Quote:
Originally Posted by jtbo
NA motor exhaust pulses are important when trying to make most power at least, those are used to flush out all exhaust gas in performance motors, for that reason measurements are rather important.
It should be possible to calculate exhaust to have best gas removal for certain rpm, as it is possible to calculate intake runners so that at certain rpm there is kind of 'boost' from recoil pulses which fills cylinders much better, exhaust must then match to intake and both need to match to cam etc. That way it is possible to get quite few % more power from engine, perhaps also better economy, but changing only one of the components is not giving much improvement if there was nothing wrong with tune up in first place.
All those + modifying cylinder head should give gains to at least older cars, where swirl is not best possible and intake manifold runners are not so good. Cylinder head modifications especially are beneficial at part throttle situations, but to get best it have to be looked as whole package.
That is at least what tiny understanding I have been given from subject.
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Well, you stated that about 1 million times more elegantly then I did. I totally agree, its the whole system that modifies performance towards a certain goal. Not just slapping on a new muffler.