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10-08-2006, 08:01 PM | #1 | ||
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What are the effects of humidity on a 1/4 mile run?
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10-08-2006, 08:19 PM | #2 | |||
trying to get a leg over
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Sweaty crotch.lol
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10-08-2006, 08:22 PM | #3 | ||
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i dont think there is alot.i did my quickest run at 98% humidity
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11-08-2006, 10:11 AM | #4 | ||
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Free water injection
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11-08-2006, 10:37 AM | #5 | ||
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Humidity if higher in my experience makes for faster 1/4 times ;)
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74 XB Fairmont (street car) 11.07@123.02mph. 08 LV Ford Focus XR5 (daily). Tuned by Hallam Performance |
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11-08-2006, 11:04 AM | #6 | ||
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Townsville. Humidity alwasy high up here.I run drags and track,and find if I venture down south with the same set up I always run better times..(ie, less humidity)IMO.
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11-08-2006, 05:34 PM | #7 | ||
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Stav realy hot days with very high humidity like the AFF day (36c 100% rh) in January most people were about .4 off there best which had a RA of about 3500ft and for every 1000ft drop in RA you should gain roughly about .15
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11-08-2006, 05:37 PM | #8 | ||
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Stav play around with this density altitude calculator and you will see the differences humitiy, air temp and ABS will affect air quality.density altitude calculator
Rembering WSID is at 230ft and take into account good air is below 1000 RA (relative altitude) |
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12-08-2006, 07:37 PM | #9 | ||
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higher humidity = less horsepower. basically, water displaces oxygen
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12-08-2006, 08:31 PM | #10 | |||
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74 XB Fairmont (street car) 11.07@123.02mph. 08 LV Ford Focus XR5 (daily). Tuned by Hallam Performance |
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12-08-2006, 09:38 PM | #11 | |||
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12-08-2006, 09:52 PM | #12 | ||
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Whats RA?
I've only ran the XB once during the day. I'd have to check my track data but I'm sure my fastest time for the day was set on a high 20's deg day. Our meets are usually night meets.
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74 XB Fairmont (street car) 11.07@123.02mph. 08 LV Ford Focus XR5 (daily). Tuned by Hallam Performance |
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12-08-2006, 10:19 PM | #13 | |||
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12-08-2006, 10:25 PM | #14 | ||
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Heathcote doesn't have the RA data on their slips. They only have barometer, temp, humidity, wind speed and wind direction.
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74 XB Fairmont (street car) 11.07@123.02mph. 08 LV Ford Focus XR5 (daily). Tuned by Hallam Performance |
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12-08-2006, 11:10 PM | #15 | |||
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13-08-2006, 11:15 AM | #16 | ||
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Brenx heres a weather conversion calculator which will convert millibars to hg (mercury), then all you need to know is the altitude of heathcote from sea level then you will be able to use the densisty altitude calculator to work out the RA.weather conversion calculator
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13-08-2006, 12:33 PM | #17 | ||
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The fact is, as stated above, dense air contains more oxygen. High humidity is not conducive to making good horsepower. Engines make more power in cold air.
If you need proof on the track have a look at how many records are set at the Winternationals at Willowbank. It's always cold, the air is usually very dense. I believe last Winters though the air was 1000 ft above sea level which is not very good for that track. If a car goes better in humid conditions than it does in cold air it may need a set up change. Remember that as the sun goes down and the air cools the track can get a mild to heavy dew on it as well. Some cars won't adapt well to the change in grip levels. It doesn't matter what opinions are here. A correctly tuned engine makes more power in cold air. Whether that can be applied to the track is a different story. |
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13-08-2006, 12:44 PM | #18 | |||
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13-08-2006, 03:17 PM | #19 | |||
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13-08-2006, 03:19 PM | #20 | |||
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Check the air temp and humidity -> http://www.users.on.net/~brenx/images/Timeslip_20_05_06.jpg Prior pbs 393 - 11.14@121.92, Air temp 25.9, humidity 31%, barameter 987 351 - 11.85@115.83 Airtemp 9.8, humidity 92%, barometer 994
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74 XB Fairmont (street car) 11.07@123.02mph. 08 LV Ford Focus XR5 (daily). Tuned by Hallam Performance Last edited by brenx; 13-08-2006 at 03:33 PM. |
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13-08-2006, 04:17 PM | #21 | |||
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But if you think humidity is better for power, no one is probably going to convince you different, so good luck!
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13-08-2006, 04:21 PM | #22 | |||
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I also stated before the last AFF drag meet the humidity would increase and the pb's would roll on. Humidity increased and the barage of pb's went through the roof. It's not just one racer. Plenty went faster with the high humidity.
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74 XB Fairmont (street car) 11.07@123.02mph. 08 LV Ford Focus XR5 (daily). Tuned by Hallam Performance |
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13-08-2006, 04:41 PM | #23 | |||
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13-08-2006, 04:52 PM | #24 | |||
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74 XB Fairmont (street car) 11.07@123.02mph. 08 LV Ford Focus XR5 (daily). Tuned by Hallam Performance |
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13-08-2006, 05:58 PM | #25 | |||
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The 11.85 run the air was 467ft (awsome air worth about .3 off ET ) Mate there was something going on with the 11.85 run also what was your 60ft for both runs as the air on that run was excellent. Out of the 3 the biggest factor is air temp to improving air density/quality dont just look at humidity, I have raced a WSID in 100% rh but the air was 15c and with a RA of 650ft quiet good air but because the humidity was so high the track was getting slipery from dew. |
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13-08-2006, 06:02 PM | #26 | |||
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74 XB Fairmont (street car) 11.07@123.02mph. 08 LV Ford Focus XR5 (daily). Tuned by Hallam Performance |
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13-08-2006, 06:07 PM | #27 | |||
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13-08-2006, 09:01 PM | #28 | ||
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Guys, you need to remember that humidity is a relative thing. 100% humidity is the maximum amount of moisture the air can absorb, but how much water it takes to reach that maximum varies significantly depending on temperature.
In a nutshell, humidity has very little effect at low temperatures. As temperatures increase, the effects of humidity increase exponentially. Imagine a room full of air at 0 deg. The amount of moisture in the air would only be a few drops. It's because :a) the air at that temperature can absorb bugger all moisture and b) any moisture at that temperature is likely to be liquid and difficult to be absorbed. If you increase the temp and add steam, you would maintain 100% humidity. At 5 degrees you would have added a cupful of water. At 10 degrees you'd need a litre. 20 degrees would need a bucket full of steam, 30 a large drum, a 44 gallon drum at 40 and so on. De-humidifiers work in reverse. They take hot, wet air and cool it down, which forces out the moisture as condensate. You end up with cold air thats still 100% humidity and a big puddle. Remove the puddle and allow the air to warm up again and you have warm, dry air. Cold air at 100% humidity can still be drier than hot air at 50%. RA is way a way of relating changing air pressure to a fixed scale between sea level and the the outer atmosphere. Imagine standing inside a huge column at sea level. The air pressure you feel is the result of gravity acting on the mass of air inside the column above you. The higher you go in the column, the less mass there is and therefore less pressure at that point. If you know your altitude, you can theoretically calculate the air pressure and vise versa. This is how plane altimeters work. If you took one to the dragstrip on day when there was a high pressure system in the area, it would read a certain altitude. Same place on a day with low pressure system in the area would make it read a lot higher altitude. Ideal conditions are low temperatures, low humidity, low altitude and high air pressure.
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13-08-2006, 09:09 PM | #29 | |||
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I've done quite a lot of racing at Heathcote raceway. I know at Heathcote as soon as the humidity rose the times fall.
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74 XB Fairmont (street car) 11.07@123.02mph. 08 LV Ford Focus XR5 (daily). Tuned by Hallam Performance |
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13-08-2006, 09:14 PM | #30 | ||
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Check your slips. I have a hunch the increase in humidity coincides with a decrease in temperatures. Cooling air means relative percentage will go up, although actual volume of moisture doesn't change much at all, unless it cools enough too reach 100%, then moisture starts getting forced out of the air as dew or condensate.
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