Forum » Understanding AFR » Maths involved in the course

Maths involved in the course

Understanding AFR

Discussion and questions related to the course Understand AFR

Page 1

Hi guys,

I don't want to sound thick but I found the maths aspect of the course was understandable but was (for me) moved through really quickly, is there any way a PDF could be created so that all the maths in this course can be read and/or printed and studied and understood better at a rate that suits someone like me?


If you feel the maths is being rushed through pause the video, rewind it back and play again. Remember once you've bought the course you can watch it as many times as you like. That way you can make your own notes that will be easy for you to understand

Thanks Chris,

Just another thing - as I'm recapping and being the total noob I am, I do have some questions that will pop up. When calculating airflow, the number 1728 is pushed in there 'as a constant' but where did that number come from?


It'll have been worked out in some engineering or physics department at a university somewhere. I'm sure if you looked into it you'd find out who worked it out but at the end of the day when working out anything using mathematics you always have a constant and the variables.

The constant in this case is the amount of cubic inches in a cubic foot, 12inches x 12 inches x 12 inches = 1728 inches = 1 foot, since air flow is calculated in cubic feet per minute and engines are measured in cubic inches you need to divide it out.

*referencing Engine Airflow HP1537, might be worth a look if you want to delve into the maths of the airflow.

We have just completed a reshoot of this course with the aim of clearing up a couple of minor issues that we had found in the original course, as well as making it clearer and easier to understand. You will have access to this new course when it is launched for free and I'd urge you to rewatch it as it is a LOT better, more interesting and more in depth.

The constant of 1728 is used to convert between cubic inches and cubic feet since there are 1728 cubic inches to a cubic foot. This is because we normally express engine capacity in cubic inches but when we start talking about airflow the numbers would be huge if we retained c.i as the unit so we normally express airflow in cubic feet. This is explained in the new course as it is a question that often crops up.