Porting School #1 - Why engines need airflow

[DavidVizard-GFN]

#1 Air Flow – Why an Engine Needs It.

By

David Vizard

The only reason you are on this site is to find out how to make more horsepower from an engine so that the vehicle it propels can be made faster. That means almost for sure that the engine concerned is an air consuming power plant and more than likely a gasoline or diesel at that. So you are looking for the holy grail of speed. I have shown it before elsewhere in GFN but the following chart contains all the subjects that you need to learn to be able to extract more power from a piston style internal combustion engine. Take a few moments and study this illustration.

What you will see is that the process of developing power starts with the engines ability to draw in air and ends with it’s ability to expel it. In short airflow through the engine is everything. The greater the weight of air induced and functionally utilized in one cycle the greater the torque output of the engine. The greater the quantity passed through the engine in a given unit of time (i.e. – lbs per minute) the higher the horsepower output. If there is any undue resistance to flow both entering and leaving the engine output will suffer.

When power is a serious pursuit, air filters, carburetors, intake manifolds, cylinder heads and exhaust systems will need to flow at their best and achieving results here dictates that a flow bench be part of the development equipment. If you are new to engine devolvement strategies you may ask ‘why not just make all the flow sensitive components big’. Surly big carbs, big ports etc will achieve big flow? Making such moves will actually make big flow numbers on a flow bench but they almost certainly won’t results in correspondingly big output numbers. Because of the gas dynamics of a running engine velocity within the various intake and exhaust tracts also plays a big part toward generating big power figures. The real key issue here is not so much big ports but ports the right size that have highly efficient flow characteristics. Developing these to as near optimal form as possible not only takes a considerable knowledge of what is required within the engine but also the skillful and intelligent use of a flow bench. That is what we plan to teach in the GFN Porting School.

David Vizard

Other parts in this series are at:


#1 Porting School #1 - Why engines need airflow

#2 Porting School #2 - Super Cheap Flow Bench

#3 Porting School #3 Budget Bench Calibration

#4 Porting School #4 - Budget Bench Electronics

#5 Porting School #5 Identifying Primary Restrictions

#6 Porting School #6 - Secrets to reduce valve shrouding

#7 Porting School #7 - Power & Port Volumes

Want to learn how to develop and port heads for high performance professionally?
If so click on the link below.

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