Did a quick search and pulled this off another forum. Here's the link if you want to cross reference.
http://www.ls1tech.com/forums/dynamometer-results-comparisons/1104917-whats-difference-std-sae-uncorrected.htmlWhen I read your question, I was like, yeah, what is the difference?
Hopefully the following info is correct. Usually try to correlate information to more than 3 sources; but in the intrest of getting somewhere with this question, posting before I got time to do this.
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I borrowed this a cobalt forum, it explains it pretty good. SAE is the standard.
There are few standards used in the dyno world for gathering HP and TQ numbers, UNCORRECTED, SAE and STD. Uncorrected is NEVER accepted in the world of dynoing and tuning as it does not factor in any weather conditions etc. Now here is where the big debate comes...is between SAE and STD. SAE (Society of Automotive Engineers) is the MOST ACCURATE AND WIDELY ACCEPTED FORM OF MEASUREMENT when it comes to the world of dynoing. Here is some more info I have gathered between the two.....
A lot of people have been asking about SAE .vs STD Dyno numbers so I thought this would help. Most people know that showing STD numbers read higher but not many know why. SAE represents more realistic standard conditions, STD artificially boosts numbers.
Identifying Your Correction Factor:
Dynojet:
If you look at a dynojet graph in the upper right corner, you will see where it says the correction method being used. The options are SAE, STD, Uncorrected and a few not needed for discussion. You will also notice a smooth factor (up to 5) which dyno operators use to make the power curves and any other data displayed, such as AFR, seem more accurate and smooth. You will also see AFR graphs scaled DOWN to hide flaws in the curve.
MD:
A Mustang Dyno ONLY uses SAE Corrections. Smoothing can also be controlled as well as scale for the Graphical Outputs.
Overview:
Most of the stated horsepower numbers are “Corrected” values. The correction standards were developed to discount the observed horsepower readings taken at different locations and weather conditions. It is obvious that an engine builder in Colorado could not produce as much horsepower as a shop at sea level. There is just less oxygen for the engine to burn at the higher altitude. What are less obvious are the other weather condition effects on the engine. So in order to compensate for this all advertised horsepower is “corrected” to several different industry standards.
SAE:
"SAE (Society of Automotive Engineers), USA. Power is corrected to reference conditions of 29.23 InHg (99 kPa) of dry air and 77 F (25°C). This SAE standard requires a correction for friction torque.
STD:
STD is Another power correction standard determined by the SAE. Power is corrected to reference conditions of 29.92 InHg (103.3 kPa) of dry air and 60 F (15.5°C). Because the reference conditions include higher pressure and cooler air than the SAE standard, these corrected power numbers will always be about 4 % higher than the SAE power numbers. Friction torque is handled in the same way as in the SAE standard."
Here is some quick math (using assumptions and round numbers):
STD:
Air Temperature: 60F
Absolute Pressure: 29.92 inches Hg
Relative Humidity: 0%
Relative Horsepower : 104.8%
Air Density: 1.223kg/m3
Relative Air Density: 99.8%
Density Altitude: 67feet
Virtual Temperature: 60F
Vapor Pressure: 0 inches Hg
Dyno Correction Factor: .955
SAE:
Air Temperature: 77F
Absolute Pressure: 29.23 inches Hg
Relative Humidity: 0%
Relative Horsepower : 100%
Air Density: 1.157kg/m3
Relative Air Density: 94.4%
Density Altitude: 1952feet
Virtual Temperature: 77F
Vapor Pressure: 0 inches Hg
Dyno Correction Factor: 1
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Topic: SAE Smoothing vs STD Smoothing (Read 14771 times)