How Much Does Density Altitude Affect ET

[340Cuda]

Originally Posted by Ralph A Powell

Percent of oxygen changes can have a big impact and since very few measure this the basic numbers can remain the same but the percentage of oxygen can change and have a large impact!

So at the same DA the percent of oxygen can be different?

How do you measure the percent of oxygen?

Thanks

[Lenny5160]

Originally Posted by 340Cuda

So at the same DA the percent of oxygen can be different?

How do you measure the percent of oxygen?

Thanks

There are many different combinations of Temperature, Relative Humidity, and Barometric Pressure that will give you the same Density Altitude, say 2500 feet. The car should perform similarly in any of those combinations that equate to a DA of 2500 feet, but it can vary depending on the exact makeup of those measures.

I'm pretty sure your weather monitor needs to have an oxygen sensor if you want that info.

[340Cuda]

Originally Posted by Lenny5160

There are many different combinations of Temperature, Relative Humidity, and Barometric Pressure that will give you the same Density Altitude, say 2500 feet. The car should perform similarly in any of those combinations that equate to a DA of 2500 feet, but it can vary depending on the exact makeup of those measures.

At first I thought there was a conflict in this statement. However are you saying at the same DA the car will perform similarly but not exactly the same depending on the differences in the factors that determine DA?

[Lenny5160]

Originally Posted by 340Cuda

At first I thought there was a conflict in this statement. However are you saying at the same DA the car will perform similarly but not exactly the same depending on the differences in the factors that determine DA?

Yes, it sounds like you understand what I was saying.

[Mike Pearson]

Originally Posted by 340Cuda

So at the same DA the percent of oxygen can be different?

How do you measure the percent of oxygen?

Thanks

You have to have a weather station that measures the percent of oxygen. I know Altronics has them as an option.

I mostly look at the humidity and the barometer to make comparisons. The 327 engine that I am running is much more difficult to dial than the 350 that I have. Must have something to do with the shorter stroke.

[SSDiv6]

Patrick Hale's book is very helpful and has lots of information on this subject.

http://www.dragracingpro.com/site/90...ooks.html#2859

[pmrphil]

Originally Posted by SSDiv6

Patrick Hale's book is very helpful and has lots of information on this subject.

http://www.dragracingpro.com/site/90...ooks.html#2859

the link doesn't work for me ???

[340Cuda]

Originally Posted by pmrphil

the link doesn't work for me ???

Try this one...

http://www.dragracingpro.com/Books.html

[pmrphil]

Originally Posted by 340Cuda

Try this one...

http://www.dragracingpro.com/Books.html

thanks

[vic guilmino]

What do you use.
DA OR CF
AND WHY