SAE corrected 409 RWHP cam-only LS1 A4!
06-06-2005, 03:08 PM
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SAE corrected 409 RWHP cam-only LS1 A4!?!? I was passed to this by my friend. My car has the cam in the sig. Again, here is my dyno graph using STD correction:
Here is his explaination. Does this make sense?
Let me help you then. 
Your dyno pull was made in High Ridge, MO at 10:52AM. Weather Underground reveals that it was 84.9*F at 10:54AM at the nearest weather station. You say it was 89 so let’s compromise and say 87*F
Next we need to go to http://www.crh.noaa.gov/lsx/calc.php and http://www.csgnetwork.com/vaporpressurecalc.html to get the station pressure and vapor pressure, both in in Hg.
Using 29.78 in Hg as the barometric pressure at that time and the 900' elevation of High Ridge we come up with a station pressure of 28.822 in Hg.
Using a temperature of 87 and a dew point of 71 we come up with a vapor pressure of 1.29 in Hg.
Finally, we plug in the numbers into the calculator and we get a correction factor (CF) of 1.085!
So your 377 actual horsepower is corrected to 409 rwhp SAE!!! Like I said, MM's dyno reads high but those are ridiculous numbers for a cam only A4 with the converter unlocked! CONGRATS!!!
My References:
Dyno Correction Factor Calculator
http://wahiduddin.net/calc/calc_cf.htm
This Correction Factor Calculator determines the dyno correction factor which is to be multiplied by the actual dyno data to make the resulting corrected readings independent of the effects of temperature, barometric pressure, humidity, and altitude. These calculations are derived from SAE J1349 Revision JUN90.
Air density is affected by the temperature, pressure and humidity of the air. On a hot day, or at high altitude, or on a moist day the air is less dense which means that there is less oxygen available for combustion which, in turn, means that there is also less engine horsepower and torque.
This calculator is specifically intended to help evaluate the data from a DynoJet chassis dyno run when you would like to know how the data would change if the temperature or pressures were different.
Drag racers and engine tuners... take a look at the features in the Engine Tuner's Calculator. The engine tuner's calculator now includes relative horsepower, air density, density altitude, virtual temperature, absolute pressure, vapor pressure, relative humidity and dyno correction factor!
To use this calculator just enter the temperature, absolute pressure and vapor pressure, then click on the calculate button.
Dyno Correction Calculator
Air Temperature in degrees F: 87
Absolute Pressure in inches Hg: 28.822
Vapor Pressure in inches Hg: 1.29
Dyno Correction Factor: 1.085
Copyright 1998-2004, Richard Shelquist
Additional Information:
For example, at 85 deg F, 24.71 in-Hg absolute pressure and 0.121 in-Hg vapor pressure, the engine only produces about 81.1% of the SAE rated power so that the required dyno correction factor is 1.233. Therefore, when dyno testing under these conditions, it is necessary to multiply the measured torque and horsepower values by the correction factor of 1.233 to determine the SAE corrected readings. The dyno correction factor takes into account all of the effects of temperature, altitude, atmospheric pressure and humidity to arrive at corrected horsepower and torque values.
The air temperature should ideally be the temperature of the air that is going into your engine.
The absolute pressure is the actual atmospheric pressure, also called station pressure. This is not the barometric pressure or altimeter setting as is typically reported on the local weather report.
Station pressure calculator: http://www.crh.noaa.gov/lsx/calc.php
The vapor pressure is the partial pressure of the water vapor in the air.
Vapor pressure calculator: http://www.csgnetwork.com/vaporpressurecalc.html
For these calculations, the standard reference conditions are: Air temp 77 deg F (25 deg C), 29.235 Inches- Hg (990 mb) altitude-corrected barometric pressure, 0 ft ( 0 m) altitude, 0% relative humidity.
Resources:
For in-depth technical details, see my web page on Dyno Correction Factor and Relative Horsepower and also see the page describing Air Density and Density Altitude.
A useful source for simple atmospheric theory, explanations and calculations is the USA Today Weather web site. Also, there are several weather conversion calculators available from El Paso NWS.
Copyright 1998-2004, All Rights Reserved, Richard Shelquist, Shelquist Engineering.
Richard Shelquist
Longmont, Colorado
Last Updated: May 24, 2005 He informed me that the cam only record is 413 RWHP. Now how can my mid-sized cam do that for me????? As much input as you can give, please.
Here is his explaination. Does this make sense?
Originally Posted by PewterZ28
Originally Posted by ragingWS6
It was 89* when I made my dyno run.
Your dyno pull was made in High Ridge, MO at 10:52AM. Weather Underground reveals that it was 84.9*F at 10:54AM at the nearest weather station. You say it was 89 so let’s compromise and say 87*F
Next we need to go to http://www.crh.noaa.gov/lsx/calc.php and http://www.csgnetwork.com/vaporpressurecalc.html to get the station pressure and vapor pressure, both in in Hg.
Using 29.78 in Hg as the barometric pressure at that time and the 900' elevation of High Ridge we come up with a station pressure of 28.822 in Hg.
Using a temperature of 87 and a dew point of 71 we come up with a vapor pressure of 1.29 in Hg.
Finally, we plug in the numbers into the calculator and we get a correction factor (CF) of 1.085!
So your 377 actual horsepower is corrected to 409 rwhp SAE!!! Like I said, MM's dyno reads high but those are ridiculous numbers for a cam only A4 with the converter unlocked! CONGRATS!!!
My References:
Dyno Correction Factor Calculator
http://wahiduddin.net/calc/calc_cf.htm
This Correction Factor Calculator determines the dyno correction factor which is to be multiplied by the actual dyno data to make the resulting corrected readings independent of the effects of temperature, barometric pressure, humidity, and altitude. These calculations are derived from SAE J1349 Revision JUN90.
Air density is affected by the temperature, pressure and humidity of the air. On a hot day, or at high altitude, or on a moist day the air is less dense which means that there is less oxygen available for combustion which, in turn, means that there is also less engine horsepower and torque.
This calculator is specifically intended to help evaluate the data from a DynoJet chassis dyno run when you would like to know how the data would change if the temperature or pressures were different.
Drag racers and engine tuners... take a look at the features in the Engine Tuner's Calculator. The engine tuner's calculator now includes relative horsepower, air density, density altitude, virtual temperature, absolute pressure, vapor pressure, relative humidity and dyno correction factor!
To use this calculator just enter the temperature, absolute pressure and vapor pressure, then click on the calculate button.
Dyno Correction Calculator
Air Temperature in degrees F: 87
Absolute Pressure in inches Hg: 28.822
Vapor Pressure in inches Hg: 1.29
Dyno Correction Factor: 1.085
Copyright 1998-2004, Richard Shelquist
Additional Information:
For example, at 85 deg F, 24.71 in-Hg absolute pressure and 0.121 in-Hg vapor pressure, the engine only produces about 81.1% of the SAE rated power so that the required dyno correction factor is 1.233. Therefore, when dyno testing under these conditions, it is necessary to multiply the measured torque and horsepower values by the correction factor of 1.233 to determine the SAE corrected readings. The dyno correction factor takes into account all of the effects of temperature, altitude, atmospheric pressure and humidity to arrive at corrected horsepower and torque values.
The air temperature should ideally be the temperature of the air that is going into your engine.
The absolute pressure is the actual atmospheric pressure, also called station pressure. This is not the barometric pressure or altimeter setting as is typically reported on the local weather report.
Station pressure calculator: http://www.crh.noaa.gov/lsx/calc.php
The vapor pressure is the partial pressure of the water vapor in the air.
Vapor pressure calculator: http://www.csgnetwork.com/vaporpressurecalc.html
For these calculations, the standard reference conditions are: Air temp 77 deg F (25 deg C), 29.235 Inches- Hg (990 mb) altitude-corrected barometric pressure, 0 ft ( 0 m) altitude, 0% relative humidity.
Resources:
For in-depth technical details, see my web page on Dyno Correction Factor and Relative Horsepower and also see the page describing Air Density and Density Altitude.
A useful source for simple atmospheric theory, explanations and calculations is the USA Today Weather web site. Also, there are several weather conversion calculators available from El Paso NWS.
Copyright 1998-2004, All Rights Reserved, Richard Shelquist, Shelquist Engineering.
Richard Shelquist
Longmont, Colorado
Last Updated: May 24, 2005
Last edited by ragingWS6; 06-06-2005 at 03:37 PM.
06-06-2005, 03:31 PM
#3
why don't you call the dyno place and they convert it for you right away using the dynojet program. it takes like 2 seconds literally. the stuff you are talking about is like ricer hp. and keep in mind you got your peak from a spike, not actual. as long as it feels good, thats what matters. but i'm sure you are no where near a cam only a4 HP record with that semi-mild cam.
06-06-2005, 03:34 PM
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Originally Posted by 2MCHPWR
why don't you call the dyno place and they convert it for you right away using the dynojet program. it takes like 2 seconds literally. the stuff you are talking about is like ricer hp. and keep in mind you got your peak from a spike, not actual. as long as it feels good, thats what matters. but i'm sure you are no where near a cam only a4 HP record with that semi-mild cam.
06-06-2005, 06:32 PM
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STD correction will be higher than SAE which most everyone goes by. SAE is what the goverment standards are. STD is a dynojet formula to make the numbers higher to appease the poeple that complain about low numbers.
http://dynojet.com/gmhtpmag3.shtml directly from dynojets website. article from GMHTP.
In the United States this is usually Society of Automotive Engineers (SAE) standard J1349 Rev JUN90. Correcting to SAE J1349 alters the data to make it seem as if it was taken when the atmospheric pressure was 29.23 in/hg., the temperature 77°F and the humidity zero.
The older PEP software (v4.x) corrects only to SAE J1349. The newest WinPEP (v6.03) corrects to not only J1349, but to other standards, including "standard corrected," popular with aftermarket manufacturers (no doubt because it uses 29.92 in/hg and 68°F' to get bigger numbers), "EEC," used in Asia and parts of Europe, and "DIN," used in Germany.
so, get one in SAE like everyone else and watch the numbers drop.
http://dynojet.com/gmhtpmag3.shtml directly from dynojets website. article from GMHTP.
In the United States this is usually Society of Automotive Engineers (SAE) standard J1349 Rev JUN90. Correcting to SAE J1349 alters the data to make it seem as if it was taken when the atmospheric pressure was 29.23 in/hg., the temperature 77°F and the humidity zero.
The older PEP software (v4.x) corrects only to SAE J1349. The newest WinPEP (v6.03) corrects to not only J1349, but to other standards, including "standard corrected," popular with aftermarket manufacturers (no doubt because it uses 29.92 in/hg and 68°F' to get bigger numbers), "EEC," used in Asia and parts of Europe, and "DIN," used in Germany.
so, get one in SAE like everyone else and watch the numbers drop.
06-07-2005, 12:22 PM
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Your friend misunderstood you as saying the 377 was literally
"actual" (i.e. UNCORRECTED HP). For that, he did the correction exactly right.
"actual" (i.e. UNCORRECTED HP). For that, he did the correction exactly right.
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06-07-2005, 01:11 PM
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Originally Posted by mrr23
STD correction will be higher than SAE which most everyone goes by. SAE is what the goverment standards are. STD is a dynojet formula to make the numbers higher to appease the poeple that complain about low numbers.
http://dynojet.com/gmhtpmag3.shtml directly from dynojets website. article from GMHTP.
In the United States this is usually Society of Automotive Engineers (SAE) standard J1349 Rev JUN90. Correcting to SAE J1349 alters the data to make it seem as if it was taken when the atmospheric pressure was 29.23 in/hg., the temperature 77°F and the humidity zero.
The older PEP software (v4.x) corrects only to SAE J1349. The newest WinPEP (v6.03) corrects to not only J1349, but to other standards, including "standard corrected," popular with aftermarket manufacturers (no doubt because it uses 29.92 in/hg and 68°F' to get bigger numbers), "EEC," used in Asia and parts of Europe, and "DIN," used in Germany.
so, get one in SAE like everyone else and watch the numbers drop.
http://dynojet.com/gmhtpmag3.shtml directly from dynojets website. article from GMHTP.
In the United States this is usually Society of Automotive Engineers (SAE) standard J1349 Rev JUN90. Correcting to SAE J1349 alters the data to make it seem as if it was taken when the atmospheric pressure was 29.23 in/hg., the temperature 77°F and the humidity zero.
The older PEP software (v4.x) corrects only to SAE J1349. The newest WinPEP (v6.03) corrects to not only J1349, but to other standards, including "standard corrected," popular with aftermarket manufacturers (no doubt because it uses 29.92 in/hg and 68°F' to get bigger numbers), "EEC," used in Asia and parts of Europe, and "DIN," used in Germany.
so, get one in SAE like everyone else and watch the numbers drop.
so as long as you use SAE corrected #'s it shouldn't make a damn bit of differnce wether you dyno in the middle of august when its 100 degrees out or in January when its 45 degrees out, the #'s would be exactly the same
06-07-2005, 01:54 PM
#9
I'm Charlie's friend. Just after posting that I caught a mistake. There were two vapor pressure numbers yielded in the vapor pressure calculator. One was saturated vapor pressure the other was actual vapor pressure. Saturated vapor pressure was the 1.29 I used. However, I should have used actual vapor pressure which is 0.76. After recalculating, the Correction Factor comes out to be 1.061, which is exactly what the dyno came up with.
So 377 x 1.061 = 399.997 rwhp
That is, if 377 was the "actual" number. I now see that it is the STD number and we do not even know the "actual" number.
Thank you. You are right. I did misunderstand. This whole time I thought his numbers were "actual" numbers. I didn't even see the STD on the sides. 
Sorry Charlie. 
Your SAE numbers will in fact be lower than STD numbers but higher than the actual numbers. 
I think Smokin01 or whatever his name is has the record at like 443 rwhp or something. The record I referred to was the ET record holders Magnus and 01-Z. They both dynoed 413 rwhp SAE. So what I was trying to say was that Charlie's SAE numbers were almost as high as the ET cam only record holders. But now we see the 377 was not actual but rather STD so nothing applies anymore. 
That is correct. No matter where you go, the SAE numbers correct to a set of standard variables (the standard reference conditions are: Air temp 77 deg F (25 deg C), 29.235 Inches- Hg (990 mb) altitude-corrected barometric pressure, 0 ft ( 0 m) altitude, 0% relative humidity.) and should be within +/- 1% of each other. There are exceptions such as turbo applications at high altitudes.
So 377 x 1.061 = 399.997 rwhp
That is, if 377 was the "actual" number. I now see that it is the STD number and we do not even know the "actual" number.
Originally Posted by Plum Crazy Rob
Your friend misunderstood you as saying the 377 was literally
"actual" (i.e. UNCORRECTED HP). For that, he did the correction exactly right.
"actual" (i.e. UNCORRECTED HP). For that, he did the correction exactly right.
Sorry Charlie. Your SAE numbers will in fact be lower than STD numbers but higher than the actual numbers.
Originally Posted by BAIN
I think the cam only record is around 430-440rwhp 
so as long as you use SAE corrected #'s it shouldn't make a damn bit of differnce wether you dyno in the middle of august when its 100 degrees out or in January when its 45 degrees out, the #'s would be exactly the same
Last edited by PewterZ28; 06-07-2005 at 02:17 PM.
06-07-2005, 02:55 PM
#10
Originally Posted by mrr23
STD is always higher than SAE. so, his figuring is way wrong. and just like everyone says here. all the guy has to do is click the drop box and select SAE.
06-07-2005, 04:01 PM
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I haven't ever locked mine up on the dyno maybe I should to see what it will do 
It put's down 381hp and 415 tq SAE Corrected with a T-Rex (cam only) through an unlocked 4400 converter.
It put's down 381hp and 415 tq SAE Corrected with a T-Rex (cam only) through an unlocked 4400 converter.
06-07-2005, 04:59 PM
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Originally Posted by JakeFusion
That's if it's cold when it's dynoed. Heat and humidity kill the STD numbers, so the SAE correction actually brings them back up.
06-07-2005, 05:22 PM
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Originally Posted by BAIN
I haven't ever locked mine up on the dyno maybe I should to see what it will do It put's down 381hp and 415 tq SAE Corrected with a T-Rex (cam only) through an unlocked 4400 converter.
It put's down 381hp and 415 tq SAE Corrected with a T-Rex (cam only) through an unlocked 4400 converter.
