Dyno elvation/temp etc correction factors?
Thread Starter
Le Mans Master
Joined: Feb 1999
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From: South Carolina
St. Jude Donor '03 & '05
Dyno elvation/temp etc correction factors?
Are there corrections for weight, temperature elevation etc for dyno runs? Just curious as there are for 1/4 mile times and speed. I used a Dyno Jet, and was curious as the elevation, based on weather stations is 1500 feet here in Hawaii. Dont ask me how, okay, it is just what the weather people say.
Team Owner
Joined: May 2002
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From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Re: Dyno elvation/temp etc correction factors? (steve40th)
The temperature and elevation corrections would be the same as for 1/4 mile runs.
As far as weight, I have no idea.. there's some rough calcs that predict 1/4 mile speed and ET based on HP.
Also, consider aero horsepower (drag) if you're trying to predict 1/4 mile times.
I have all the calcs on my computer, they're pretty scary looking equations. Relative Humidity, dewpoint, virtual vapor pressures, all kinds of crap.
if you give me the weather readings and the rwhp output i can tell you the corrected rwhp and bhp.
As far as weight, I have no idea.. there's some rough calcs that predict 1/4 mile speed and ET based on HP.
Also, consider aero horsepower (drag) if you're trying to predict 1/4 mile times.
I have all the calcs on my computer, they're pretty scary looking equations. Relative Humidity, dewpoint, virtual vapor pressures, all kinds of crap.
if you give me the weather readings and the rwhp output i can tell you the corrected rwhp and bhp.
Thread Starter
Le Mans Master
Joined: Feb 1999
Posts: 9,926
Likes: 38
From: South Carolina
St. Jude Donor '03 & '05
Re: Dyno elvation/temp etc correction factors? (CentralCoaster)
Temp was 90 degrees, elevation 1500, dew point 66, HG 30 in, but I dont know Virtual vapor here in hawaii. Rwhp was 400.
Team Owner
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From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Re: Dyno elvation/temp etc correction factors? (steve40th)
i need the humidity also.
this determines the virtual vapor pressure i think. I don't remember the equations exactly, I put em all in Excel.
But gimme a guesstimate on humidity and i'll plug it in to the formula. It doesn't affect it that much, but every bit of accuracy is helpful.
That sounds like it'll be a really high DA! That means your horsepower will go up considerably. :cheers:
this determines the virtual vapor pressure i think. I don't remember the equations exactly, I put em all in Excel.
But gimme a guesstimate on humidity and i'll plug it in to the formula. It doesn't affect it that much, but every bit of accuracy is helpful.
That sounds like it'll be a really high DA! That means your horsepower will go up considerably. :cheers:
Team Owner
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From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Re: Dyno elvation/temp etc correction factors? (CentralCoaster)
1500 ft is the elevation correct, not the DA? I guess it just seemed high to me. But then, Hawaii is just a big volcano anyways.
Team Owner
Joined: May 2002
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From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Re: Dyno elvation/temp etc correction factors? (steve40th)
Hmm. I'm showing a DA of 2200... assuming a 50% humidity.
But the correction factor is .987.... so, corrected rwhp = 395
If the DA is zero, the RWHP should be 1.00000 right? My equations must be flawed, i'll have to go back and double check.
That DA is correct though. The elevation isn't taken into account because it affects baro pressure which is already being measured.
But the correction factor is .987.... so, corrected rwhp = 395
If the DA is zero, the RWHP should be 1.00000 right? My equations must be flawed, i'll have to go back and double check.
That DA is correct though. The elevation isn't taken into account because it affects baro pressure which is already being measured.
