Impact of water grain and % oxygen

[Ralph A Powell]

It’s is the system to with the optional Oxygen meter.

[Charles Stewart]

Originally Posted by SSDiv6

Charles,
If you want to learn all about weather correction, get Patrick Hale's book, "Motorsports Standard Atmosphere and Weather Correction Methods".

https://dragracingpro.com/books

The book is considered the best on its subject.

Also, for software, I recommend Performance Trends "Weather Wiz".
Extremely accurate, as long as data inputs are good.

http://performancetrends.com/Weather-Wiz.htm

Thanks for your precious input SSDiv6,
I own a copy of Mr. Hale book and I have read and re-read that book quite a few time.
May be it's time to do it again because I'm mssing something here.
I will also take a close look at the Weather Wiz.
Keep on,

[Charles Stewart]

"Typically, we ASSUME a constant percentage of oxygen (20.90%) within that density. The only way to determine the actual percentage of oxygen and therefore the actual amount of oxygen per volume is by specifically measuring the oxygen level independently from the temp, hum and press."

Thanks Mr. Bartoli for your precious input.
That was exactly the purpose of my question. I doubted something was missing in my weather calculation and I was also assuming a constant percentage of oxygen.
keep on coaching us...

[Ralph A Powell]

When we were monitoring Oxygen at the track we were at the Texas Motorplex on Saturday the wind was blowing from Dallas towards the south on Sunday morning it had changed to coming up from the gulf with same Baro and temp. On the Oxygen meter there was a 1% increase oxygen available and it showed in performance of Fuel Cars and Pro stock.

[Charlie Yannetti]

I was going to suggest a decent weather station, but Altronics beat me to it.. I have a Crew Chief Pro system in my trailer, and couldn't believe all the options available for predicting the weather, pertaining to throttle stop and ET predictions.. you will not be dis-satisfied making that move, if you haven't already..

I always looked at density altitude, (DA), while trying to dial, but learned that it is the formula that goes into arriving at the DA that is more important.. that being said, I'll tell you that grains of water and vapor pressure are pretty important.. the higher they go, the slower you go..

[Charles Stewart]

Originally Posted by Ralph A Powell

When we were monitoring Oxygen at the track we were at the Texas Motorplex on Saturday the wind was blowing from Dallas towards the south on Sunday morning it had changed to coming up from the gulf with same Baro and temp. On the Oxygen meter there was a 1% increase oxygen available and it showed in performance of Fuel Cars and Pro stock.

I must add this previous post from Don Sofranko to this fact:
Re: "Live From" Indy US Nationals The Big GO 2022
Just a curious question after watching the big race from home on NHRA tv

As a past racer at the big go, its always a challenge with the big delays in hours or days between rounds. I was amazed that a bunch, if not all the guys on Monday slowed more than expected, from the early Monday R4 to R5 (3:30 PM) in super stock, and also similar in R5 to R6 Stock. It seems like with all the modern weather stations, and other data that it would have been detectable, to see a slowdown.

Am I wrong or is there another reason for everyone missing the dial by what looks like .03-.04?

Why do the modern weather stations not always tell the picture?
This was from early Monday to the 3:30 afternoon round

[Lenny5160]

Originally Posted by Ralph A Powell

When we were monitoring Oxygen at the track we were at the Texas Motorplex on Saturday the wind was blowing from Dallas towards the south on Sunday morning it had changed to coming up from the gulf with same Baro and temp. On the Oxygen meter there was a 1% increase oxygen available and it showed in performance of Fuel Cars and Pro stock.

I’m curious if there were any other apparent changes when this happened. Especially pertaining to Grains/Dew Point.

[Ralph A Powell]

Originally Posted by Lenny5160

I’m curious if there were any other apparent changes when this happened. Especially pertaining to Grains/Dew Point.

No but you could haze coming out of Dallas