Dyno testing
Thread Starter
Instructor
Joined: Jun 2010
Posts: 160
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From: Spring Lake Michigan
Dyno testing
Has anyone dynoed their Vette in -----85 degree --high humidity----vs----50 degree--low humidity---Same car, same mods----How much difference was there in RWHP ???? How about the difference in your 1/4 mile times under each of these circumstances ?? Seems like in the cooler fall weather, the Vette seems to be much stronger, often wondered if it was mostly our imagination or not !!----THANKS !!
Race Director
Joined: Mar 2005
Posts: 11,549
Likes: 27
From: Southampton NJ
Has anyone dynoed their Vette in -----85 degree --high humidity----vs----50 degree--low humidity---Same car, same mods----How much difference was there in RWHP ???? How about the difference in your 1/4 mile times under each of these circumstances ?? Seems like in the cooler fall weather, the Vette seems to be much stronger, often wondered if it was mostly our imagination or not !!----THANKS !!
Safety Car
Joined: Nov 2010
Posts: 3,725
Likes: 84
From: Woodlands (houston) TX
yes the cold air makes more power. as the cold air is more dense which means more oxygen molecules per cubic foot of air. true the dyno is supposed to correct for temp/humidity/elevation etc. but i have seen a diff of as much as 15 hp from middle of summer to winter on the same car.
Melting Slicks
Joined: Feb 2004
Posts: 3,307
Likes: 111
From: Tucson AZ
A dyno corrects ambient temp, pressure altitude, and humidity for a standard day. A standard day is 60 degree F, 0% humidity, and 29.92 inches of mercury. It is actually possible to get a higher dyno number on a hot day than a cold day because of the correction factor.
A temp change from 85 to 50 degrees will make a large change in performance at the drag strip. The other large factor is the pressure altitude. Humidity affects density altitude, but not nearly as much as temp and pressure. NHRA has a correction factor formula they used to use for National records. They discontinued it for the Pro classes as Phoenix in Feb has very dense air (in spite of the elevation) and had several of the records.
A temp change from 85 to 50 degrees will make a large change in performance at the drag strip. The other large factor is the pressure altitude. Humidity affects density altitude, but not nearly as much as temp and pressure. NHRA has a correction factor formula they used to use for National records. They discontinued it for the Pro classes as Phoenix in Feb has very dense air (in spite of the elevation) and had several of the records.
