How much can Humidity slow down a n/a car?

[xtweakerx]

wondering if its say about 84% Humidity 79 degree's but feels like 84.

Can that have an impact of slowing a car down a tenth or two vs.

when its like 54% Humidity and 70 degree's out.


could it make the difference of going 13.20 in 84% Humidity and going 13.00 in 54% Humidity?

 

[Five Oh Brian]

Click here and you can plug in various humidity figures and see for yourself.

For example, let's say your track is 500' above sea level and you run a 13.20 @ 105 mph when the weather was 79 degrees, 84% humidity, and a barometer of 30.00. These conditions are the equivalent of trying to race on a track over 2000' above sea level (where the air is thinner and cars make less power!). Corrected for sea level, your car would have run 12.88 @ 107.58 mph.

Ideally, the best weather for making power is colder, less humid, and a higher barometer reading.

 

[xtweakerx]

sick tool.

my track web site says its 23Ft Above Sea Level so would i just put that in the Track Alt.(ft.) field?

I was just playing with it and i dont feel so bad now bout running 13.20's last night back to back i figure'd it would go 13.0 or 12.9 but it was so god damn humid and sticky/hot yesterday = { and after punching my value's into that web site it said i should of been going 13.00's.

 

[xtweakerx]

dang! just got actual values for yesterday when i was racing plugged it into the calculator and it said i should of gone 12.99 if i didnt have such poor weather.

 

[ski]

The more O2(oxygen) an engine sucks in, the more fuel the ECM sends thru the injectors for the engine to burn, and the more power it produces. Humidity is tiny water droplets that displace the air, and thus displace the O2 in the air. Thus, high humidity means less oxygen, which results in less fuel being fed into the engine, and thus less power.
Also, high ambient temperatures cause the ECM to pull timing, which further reduces the engine's power output.
Hot, sticky weather sucks for drag racing. So does high altitude.

 

[Five Oh Brian]

sick tool.

my track web site says its 23Ft Above Sea Level so would i just put that in the Track Alt.(ft.) field?

I was just playing with it and i dont feel so bad now bout running 13.20's last night back to back i figure'd it would go 13.0 or 12.9 but it was so god damn humid and sticky/hot yesterday = { and after punching my value's into that web site it said i should of been going 13.00's.

Yes, put your track's actual altitude (23') in that field. Amazing how much weather can wreak havoc with an engine's power producing ability, isn't it?

Our local track has a huge weather station on top of the tower that displays all the vital stats and produces the Density Altitude (DA) calculation. Our track is only 250' above sea level, but I've raced on days when the weather was so bad that the DA was calculating over 3000' equivalent above sea level making my car run much slower than normal - as much as .3 second and 3 mph worse than days I've gone in decent weather.

 

[gmantheman]

The 1/8 track I sometimes go to has a denstiy altitude of 4000-4500' in the summer. Talk about slowing your car down. My avg run is about 9.3 with a best of 8.8