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DRR Pro
Picture of 00 DEAD ON
posted
Running Alky what do most keep track of in your log book. What do you watch the most from day to day as far as the weather that makes your car change ET
Thx in advance


Brian Mollison
2009 RaceTech Dragster
2020 Sumerduck Dragway VA Top ET Champion
2017 Sumerduck Top ET & SSS Track Champion
2017 MAC Top ET Track Champion
2009 Sumerduck Dragway Va Top ET & IHRA SSS Track Champion
2008 IHRA Division 1 Top ET Bracket Final Runner-up
2007 Colonial Beach Dragway Top ET Track Champion
 
Posts: 1026 | Location: Stafford, Virginia | Registered: October 03, 2006Reply With QuoteReport This Post
DRR S/Pro
Picture of Lenny5160
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On a run-to-run basis, the #1 thing I look at is Dew Point. Grains will give you exactly the same thing but I use DP.

An increase of 5-6 grains or 2* of DP will slow me .01 in the quarter.

I'm not nearly as strong trying to predict off the trailer when a lot of things have moved dramatically. Especially a big change in the barometer.


Tony Leonard
 
Posts: 3154 | Location: Inver Grove Heights, MN | Registered: March 18, 2004Reply With QuoteReport This Post
DRR S/Pro
Picture of Big Steve
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Water grains for sure at the top of my list
 
Posts: 2422 | Location: Moving back to the door side | Registered: April 30, 2010Reply With QuoteReport This Post
DRR S/Pro
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As noted above but you do need to pay attention to temp also and how it effect humidity. If you see temp go down and humidity drop too, your gonna pick up big time vs temp dropping and humidity rising where they may cancel each other out. On a given day the barometer doesn't usually move enough to matter
 
Posts: 2149 | Location: Tewksbury, MA,USA | Registered: November 03, 2000Reply With QuoteReport This Post
DRR S/Pro
Picture of Lenny5160
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quote:
Originally posted by TOP38:
As noted above but you do need to pay attention to temp also and how it effect humidity. If you see temp go down and humidity drop too, your gonna pick up big time vs temp dropping and humidity rising where they may cancel each other out. On a given day the barometer doesn't usually move enough to matter


Top, you are the first person to mention Humidity. If you are talking about Relative Humidity, measured in a %, you shouldn't be using that.

It can have some value as there can be performance cliffs associated with saturation, but Water Grains and DP give a true measure of moisture in the air and do not move based solely on a change in temperature or pressure.


Tony Leonard
 
Posts: 3154 | Location: Inver Grove Heights, MN | Registered: March 18, 2004Reply With QuoteReport This Post
DRR Sportsman
Picture of Steve from Pa
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Water grains for sure is our #1 thing, but were more toward 9 grains / .01, then wind, then DA for us.
I can't stand to look at humidity anymore, just way easier for me to understand water grains.


Most important, keep the shiny side up
 
Posts: 798 | Location: Punxsutawney, Pa USA | Registered: February 05, 2001Reply With QuoteReport This Post
DRR Sportsman
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Water grains.. But if your serious. Invest in ifamily software.

Hate to even offer that advise as people I race against who are probably reading. Off there trailer it's spot on. Don't even think about it anymore.

Here are some pointers though..I never touch anything and do everything there same. Down to fuel to exact levels every run. In can skip to weeks and hot the track and it's dead on. If I change anything it's time trials and base all runs off that.

My car varies .oox to .01x thru the day. And honestly when I lose its me.

The key is having a very car that works and not touching a thing... Then you have a fighting chance.



Configuration: 3350#, 582 C.I.,

60 - 1.24
1/8 - 5.53@ 126MPH
1/4 - 8.73@ 159MPH



3700#+210lb driver, FULL interior, through mufflers, 10.5 tire.
60'-1.333 (IN 4000ft DA! Joisy Math excluded; 1.25sec using JOISY MATH.) Wink
1/4 - 9.60@144MPH

 
Posts: 1438 | Location: St Marys | Registered: January 12, 2004Reply With QuoteReport This Post



DRR Elite
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Water grains is linear with dew point. I use dew point for water. When the dew point approaches the actual temperature, I expect at least one bad run.


Foxtrot Juliet Bravo
 
Posts: 6398 | Location: Illinois | Registered: July 08, 2004Reply With QuoteReport This Post
DRR S/Pro
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quote:
Originally posted by Lenny5160:
quote:
Originally posted by TOP38:
As noted above but you do need to pay attention to temp also and how it effect humidity. If you see temp go down and humidity drop too, your gonna pick up big time vs temp dropping and humidity rising where they may cancel each other out. On a given day the barometer doesn't usually move enough to matter


I was referring to humidity, not relative humidity. RH is OK also if you understand what it means! Bottom line is how much water is in the air is what is important.

Top, you are the first person to mention Humidity. If you are talking about Relative Humidity, measured in a %, you shouldn't be using that.

It can have some value as there can be performance cliffs associated with saturation, but Water Grains and DP give a true measure of moisture in the air and do not move based solely on a change in temperature or pressure.
 
Posts: 2149 | Location: Tewksbury, MA,USA | Registered: November 03, 2000Reply With QuoteReport This Post
DRR S/Pro
Picture of Lenny5160
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quote:
Originally posted by TOP38:
I was referring to humidity, not relative humidity. RH is OK also if you understand what it means! Bottom line is how much water is in the air is what is important.


I know you've been around and know what you're doing, Al.

I mostly wanted to clarify for anyone reading the thread looking for advice, that what most people refer to as 'Humidity' is not the best thing to use as a reference for racing air quality.


Tony Leonard
 
Posts: 3154 | Location: Inver Grove Heights, MN | Registered: March 18, 2004Reply With QuoteReport This Post
DRR Trophy
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I am on gas what is one of the indicator to use for prediction?
 
Posts: 9 | Location: Massillon, Ohio  | Registered: October 09, 2003Reply With QuoteReport This Post
DRR Elite
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quote:
Originally posted by Lenny5160:
quote:
Originally posted by TOP38:
I was referring to humidity, not relative humidity. RH is OK also if you understand what it means! Bottom line is how much water is in the air is what is important.


I know you've been around and know what you're doing, Al.

I mostly wanted to clarify for anyone reading the thread looking for advice, that what most people refer to as 'Humidity' is not the best thing to use as a reference for racing air quality.


I agree that RH is a pretty bad unit to use. I used it for years, and had to kind of take into consideration the affect that changing temperature was having on the RH...with no real change in the amount of water in the air.


Foxtrot Juliet Bravo
 
Posts: 6398 | Location: Illinois | Registered: July 08, 2004Reply With QuoteReport This Post
DRR Sportsman
Picture of Steve from Pa
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quote:
Water grains is linear with dew point. I use dew point for water. When the dew point approaches the actual temperature, I expect at least one bad run.


X2 forgot to mention that with in 3 or 4 degrees of the D.P. were going to loose .02


Most important, keep the shiny side up
 
Posts: 798 | Location: Punxsutawney, Pa USA | Registered: February 05, 2001Reply With QuoteReport This Post
DRR Sportsman
Picture of TomR
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I log temp, humidity, barometer, altitude, dew point.


72 Nova "Hooptie"
 
Posts: 739 | Location: Hanover, MD | Registered: June 20, 2016Reply With QuoteReport This Post



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