What's the difference between SAE and STD
11-06-2002, 05:58 PM
#1
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What's the difference between SAE and STD
What's the difference between SAE and STD horsepower. i dynoed my car today and only had 200.4 max HP. i have a full exhaust and intake. 
My numbers are STD.
My numbers are STD.
11-06-2002, 08:05 PM
#2
Suzuka Master
Before you waste your time moving around in the stuff I left you, consider getting a 3.5" floppy of your runs (with the "raw" data) and getting a copy of WinPep software; it should allow you to “correct” to SAE…
Here is a link:
http://grove.ufl.edu/~fnaja/files/cpm07302.htm
Move down to this section:
Engines are rated at standard conditions:
~ 60°F; 29.92 inches hg (sea level pressure)
~ other temperatures & altitudes may be used
Engine hp decreases as temperature increases. HP T
Engine hp decreases as altitude increases. HP Alt.
(See Tables 4-5 & 4-6, pgs. 82 & 83 in textbook)
where: HPavail =horsepower available
Pactual =altitude at which the machine will be operated in inches Hg (inches of mercury) barometric pressure (see Table 4-6)
Pstd =standard condition altitude, usually sea level, 29.9 in. Hg
Tactual =Rankine temperature at which the machine will be operated
Tstd =standard condition temperature in Rankine units, usually 60°F, which equals 520°R
http://www.icelord.net/vw/upgrades/P...rrections.html
There are a couple of tables at the bottom for SAE standard:
Here is a link:
http://grove.ufl.edu/~fnaja/files/cpm07302.htm
Move down to this section:
Engines are rated at standard conditions:
~ 60°F; 29.92 inches hg (sea level pressure)
~ other temperatures & altitudes may be used
Engine hp decreases as temperature increases. HP T
Engine hp decreases as altitude increases. HP Alt.
(See Tables 4-5 & 4-6, pgs. 82 & 83 in textbook)
where: HPavail =horsepower available
Pactual =altitude at which the machine will be operated in inches Hg (inches of mercury) barometric pressure (see Table 4-6)
Pstd =standard condition altitude, usually sea level, 29.9 in. Hg
Tactual =Rankine temperature at which the machine will be operated
Tstd =standard condition temperature in Rankine units, usually 60°F, which equals 520°R
http://www.icelord.net/vw/upgrades/P...rrections.html
There are a couple of tables at the bottom for SAE standard:
Code:
Correction Factors for Various Ambient Conditions
=================================================
SAE Standard Conditions: 29.23 inHg, 77ˇF, 18% Efficiency
Determine ambient barometric pressure (Pa), ambient temp (Ta), and
ambient relative humidity (RH).
Using Table 1, find the vapor pressure correction for the RH and Ta
of the test conditions. SUBTRACT this correction from the Pa.
Then use the newly correctec dry ambient pressure (Pd) and Ta in
Table 2 to find the correction factor to multiple times the observed
power or torque readings.
For ordinates not in tables, interpolation is acceptable.
-----------------------------------------------------------------------------------
TABLE 1 - Vapor Pressure Correction vs. Humidity and Temperature:
RH Ambient Temperature (ˇF)
(%), 0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120
0,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00
10,0.00,0.01,0.01,0.02,0.02,0.04,0.05,0.07,0.10,0.14,0.19,0.26,0.34
20,0.01,0.01,0.02,0.03,0.05,0.07,0.10,0.15,0.21,0.28,0.39,0.52,0.69
30,0.01,0.02,0.03,0.05,0.07,0.11,0.16,0.22,0.31,0.43,0.58,0.78,1.03
40,0.02,0.03,0.04,0.07,0.10,0.15,0.21,0.30,0.41,0.57,0.77,1.04,1.38
50,0.02,0.04,0.05,0.08,0.12,0.18,0.26,0.37,0.52,0.71,0.97,1.30,1.72
60,0.03,0.04,0.07,0.10,0.15,0.22,0.31,0.44,0.62,0.85,1.16,1.56,2.07
70,0.03,0.05,0.08,0.12,0.17,0.25,0.37,0.52,0.72,1.00,1.35,1.82,2.41
80,0.04,0.06,0.09,0.13,0.20,0.29,0.42,0.59,0.83,1.14,1.55,2.08,2.76
90,0.04,0.06,0.10,0.15,0.22,0.33,0.47,0.67,0.93,1.28,1.74,2.34,3.10
100,0.04,0.07,0.11,0.17,0.25,0.36,0.52,0.74,1.03,1.42,1.93,2.60,3.45
-----------------------------------------------------------------------------------
TABLE 2 - Correction to Power/Torque at Ambient Temperature and Pressure:
Pd Ambient Temperature (ˇF)
("Hg), 0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120
24.00,1.150,1.165,1.179,1.193,1.207,1.221,1.234,1.248,1.261,1.274,1.288,1.301,1.314
24.25,1.136,1.151,1.165,1.179,1.192,1.206,1.220,1.233,1.246,1.259,1.272,1.285,1.298
24.50,1.123,1.137,1.151,1.165,1.178,1.192,1.205,1.219,1.232,1.245,1.258,1.270,1.283
24.75,1.110,1.124,1.138,1.151,1.165,1.178,1.191,1.204,1.217,1.230,1.243,1.256,1.268
25.00,1.097,1.111,1.124,1.138,1.151,1.165,1.178,1.191,1.204,1.216,1.229,1.241,1.254
25.25,1.084,1.098,1.111,1.125,1.138,1.151,1.164,1.177,1.190,1.202,1.215,1.227,1.240
25.50,1.072,1.085,1.099,1.112,1.125,1.138,1.151,1.164,1.176,1.189,1.201,1.214,1.226
25.75,1.060,1.073,1.086,1.100,1.113,1.125,1.138,1.151,1.163,1.176,1.188,1.200,1.212
26.00,1.048,1.061,1.074,1.087,1.100,1.113,1.125,1.138,1.150,1.163,1.175,1.187,1.199
26.25,1.036,1.049,1.062,1.075,1.088,1.100,1.113,1.125,1.138,1.150,1.162,1.174,1.186
26.50,1.025,1.038,1.051,1.063,1.076,1.088,1.101,1.113,1.125,1.137,1.149,1.161,1.173
26.75,1.013,1.026,1.039,1.052,1.064,1.077,1.089,1.101,1.113,1.125,1.137,1.148,1.160
27.00,1.002,1.015,1.028,1.040,1.053,1.065,1.077,1.089,1.101,1.113,1.125,1.136,1.148
27.25,0.991,1.004,1.017,1.029,1.041,1.054,1.066,1.077,1.089,1.101,1.113,1.124,1.135
27.50,0.981,0.993,1.006,1.018,1.030,1.042,1.054,1.066,1.078,1.089,1.101,1.112,1.123
27.75,0.970,0.983,0.995,1.007,1.019,1.031,1.043,1.055,1.066,1.078,1.089,1.101,1.112
28.00,0.960,0.972,0.985,0.997,1.009,1.020,1.032,1.044,1.055,1.067,1.078,1.089,1.100
28.25,0.950,0.962,0.974,0.986,0.998,1.010,1.021,1.033,1.044,1.056,1.067,1.078,1.089
28.50,0.940,0.952,0.964,0.976,0.988,0.999,1.011,1.022,1.034,1.045,1.056,1.067,1.078
28.75,0.930,0.942,0.954,0.966,0.978,0.989,1.001,1.012,1.023,1.034,1.045,1.056,1.067
29.00,0.921,0.933,0.944,0.956,0.968,0.979,0.990,1.002,1.013,1.024,1.035,1.045,1.056
29.25,0.911,0.923,0.935,0.946,0.958,0.969,0.980,0.991,1.002,1.013,1.024,1.035,1.045
29.50,0.902,0.914,0.925,0.937,0.948,0.959,0.971,0.982,0.992,1.003,1.014,1.025,1.035
29.75,0.893,0.905,0.916,0.927,0.939,0.950,0.961,0.972,0.983,0.993,1.004,1.014,1.025
30.00,0.884,0.896,0.907,0.918,0.929,0.940,0.951,0.962,0.973,0.984,0.994,1.005,1.015
30.25,0.875,0.887,0.898,0.909,0.920,0.931,0.942,0.953,0.963,0.974,0.984,0.995,1.005
30.50,0.867,0.878,0.889,0.900,0.911,0.922,0.933,0.943,0.954,0.964,0.975,0.985,0.995
30.75,0.858,0.869,0.880,0.891,0.902,0.913,0.924,0.934,0.945,0.955,0.965,0.976,0.986
31.00,0.850,0.861,0.872,0.883,0.894,0.904,0.915,0.925,0.936,0.946,0.956,0.966,0.976
-----------------------------------------------------------------------------------
EXAMPLE: Ambient pressure (Pa) = 29.04 inHg
Ambient temp (Ta) = 50 degF
Ambient humidity (RH) = 80%
>From Table 1, the vapor pressure correction is 0.29 inHg.
The dry ambient pressure (Pd) is therefore 29.04 - 0.29 = 28.75 inHg.
>From Table 2, the power correction is 0.989; or the observed power is
about 11% higher than standard conditions.
11-07-2002, 09:37 PM
#5
Suzuka Master
Originally posted by bnavarro
i have the dyno sheets, but that's it.
i have the dyno sheets, but that's it.
Have you called the dyno shop and asked them about any of this?????
11-08-2002, 12:51 AM
#6
Suzuka Master
Here is a link of some use (for use after you call your dyno guy).
http://www.wunderground.com/history/...lyHistory.html
Please don’t use or do this first (it’s just a way of getting local weather if needed):
It will give you the min/max temps, humidity (from dew point), barometric pressure. (There are humidity by hour of the day in some of the charts…)
The link I left is for Central Park, NY on 11-4-2002
You should be able to go to the page and change the date to suit.
If your dyno operator is not a clown, you should be able to get the info you need.
The tables I gave you are easy to use to correct your HP to SAE (that presumes that you have UNCORRECTED NUMBERS). STD gets corrected to a different value from the SAE standard.
IF you had UNCORRECTED numbers you would:
The first table is used to enter the humidity and temperature to get a "correction factor #1"
This "correction factor #1" is subtracted from the barometric pressure that you will see on your dyno printout (or that you get from the weather page).
(ALL YOU ARE DOING IS "ADJUSTING" the barometric pressure in step one)
Once you get your new barometric pressure, you plug that "corrected barometric" pressure and temp into Table #2. This will give you a number to multiply your HP (in your dyno) by.
Example:
I assume that 11-06-2002 is the date of the dyno from your initial posting date.
I look up your weather from that link:
Mean Temp = 46-degrees F
Standard Pressure = 29.5 "
Dew Point = 41.9F
Depending on the time of day (lower in the page) the humidity ranged from 100-percent @ 12:51AM to 58% @ 8PM.
For table 1, I'll just use 100% humidity and 50-degrees (close enough)
0.36 is what I get at the intersection of the two values.
I do my first adjustment:
29.5" (your uncorrected barometric pressure) - 0.36 (correction factor from table 1) = 29.14.
Corrected barometric pressure == 29.14"
Plug the 29.14 and 50-degreees into table #2:
I get 0.969.
I now multiply the 0.969 by your 200.4 HP and get a correct value of 194.2 SAE HP (this assumes that there was no correction(s) done to the raw HP/TQ figures -- it is for reference purposes only).
NOTE: I am just showing you how the tables work with uncorrected data. I don't have the humidity values for STD, so, one of the corrections into the first table would have to go.
STD to SAE using just your value and what I believe to be correct about STD being the same as "standard conditions":
Now, I'll do the same correction, but I'll leave out the table 1 lookup, since I can't find a reference for humidity!
Using the definition of STD as "standard conditions", I'll take your 200.4 hp and use the standard conditions of 68F and 29.92 of pressure (I'm figuring that this is the HP corrected to the temp and pressure shown above (which is slightly different from SAE).
Forget the table 1 lookup (right or wrong -- whatever). (There will be no correction for humidity):
I put 68F and 29.92" into table 2 and get a correction of 0.962.
I multiply your 200.4 x 0.962 and get 192.8 SAE HP
BTW -- The STD values were located in the data I gave you. If you had the Winpep software (with original data) you can get SAE in lieu of STD. The RAW data into WinPep will give you your choice of numbers. Bring a 3.5" floppy to the dyno shop next time and get a copy of the latest WinPep software!
I dragged this off another search engine and at least confirms the original information (second source). Be careful with that 4% remark -- that value can change!
LINK: http://forums.corvetteforum.com/zerothread?id=372923
"STD corrected dyno is about 4% higher than an SAE corrected dyno. The basic difference is the assumptions used for "baseline" conditions (IE: temperature, baramoter, humidity, etc...)
<start quote>
--------------------------------------------------------------------------------
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.
--------------------------------------------------------------------------------
http://www.dynojet.com/gmhtpmag3.shtml
your best bet is to download the dynojet viewer from the above website and take a 3 1/2" floppy to your next dyne session. They should be able to save the file for your runs which you can later view on the program.
You can change all kinds of factors, like the correction (STD, SAE, ACTUAL, EEC, DIN), the smoothing factor (1-5), the display values, etc. You can save your runs from different days/mod conditions and "overlay them to really compare the curves (not just the old "useless" peak number comparisons).
It's really cool for a free program and makes you realize how easy it is for tuners/performance shops to "fudge" the numbers if they so choose. Just changing the smoothing factor alone can have quite an affect on the peak numbers (which, personally, I think are very poor to ever report. Too many things can happen like spikes caused at the end of a run due to hitting the rev limiter).
<end quote>
http://www.wunderground.com/history/...lyHistory.html
Please don’t use or do this first (it’s just a way of getting local weather if needed):
It will give you the min/max temps, humidity (from dew point), barometric pressure. (There are humidity by hour of the day in some of the charts…)
The link I left is for Central Park, NY on 11-4-2002
You should be able to go to the page and change the date to suit.
If your dyno operator is not a clown, you should be able to get the info you need.
The tables I gave you are easy to use to correct your HP to SAE (that presumes that you have UNCORRECTED NUMBERS). STD gets corrected to a different value from the SAE standard.
IF you had UNCORRECTED numbers you would:
The first table is used to enter the humidity and temperature to get a "correction factor #1"
This "correction factor #1" is subtracted from the barometric pressure that you will see on your dyno printout (or that you get from the weather page).
(ALL YOU ARE DOING IS "ADJUSTING" the barometric pressure in step one)
Once you get your new barometric pressure, you plug that "corrected barometric" pressure and temp into Table #2. This will give you a number to multiply your HP (in your dyno) by.
Example:
I assume that 11-06-2002 is the date of the dyno from your initial posting date.
I look up your weather from that link:
Mean Temp = 46-degrees F
Standard Pressure = 29.5 "
Dew Point = 41.9F
Depending on the time of day (lower in the page) the humidity ranged from 100-percent @ 12:51AM to 58% @ 8PM.
For table 1, I'll just use 100% humidity and 50-degrees (close enough)
0.36 is what I get at the intersection of the two values.
I do my first adjustment:
29.5" (your uncorrected barometric pressure) - 0.36 (correction factor from table 1) = 29.14.
Corrected barometric pressure == 29.14"
Plug the 29.14 and 50-degreees into table #2:
I get 0.969.
I now multiply the 0.969 by your 200.4 HP and get a correct value of 194.2 SAE HP (this assumes that there was no correction(s) done to the raw HP/TQ figures -- it is for reference purposes only).
NOTE: I am just showing you how the tables work with uncorrected data. I don't have the humidity values for STD, so, one of the corrections into the first table would have to go.
STD to SAE using just your value and what I believe to be correct about STD being the same as "standard conditions":
Now, I'll do the same correction, but I'll leave out the table 1 lookup, since I can't find a reference for humidity!
Using the definition of STD as "standard conditions", I'll take your 200.4 hp and use the standard conditions of 68F and 29.92 of pressure (I'm figuring that this is the HP corrected to the temp and pressure shown above (which is slightly different from SAE).
Forget the table 1 lookup (right or wrong -- whatever). (There will be no correction for humidity):
I put 68F and 29.92" into table 2 and get a correction of 0.962.
I multiply your 200.4 x 0.962 and get 192.8 SAE HP
BTW -- The STD values were located in the data I gave you. If you had the Winpep software (with original data) you can get SAE in lieu of STD. The RAW data into WinPep will give you your choice of numbers. Bring a 3.5" floppy to the dyno shop next time and get a copy of the latest WinPep software!
I dragged this off another search engine and at least confirms the original information (second source). Be careful with that 4% remark -- that value can change!
LINK: http://forums.corvetteforum.com/zerothread?id=372923
"STD corrected dyno is about 4% higher than an SAE corrected dyno. The basic difference is the assumptions used for "baseline" conditions (IE: temperature, baramoter, humidity, etc...)
<start quote>
--------------------------------------------------------------------------------
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.
--------------------------------------------------------------------------------
http://www.dynojet.com/gmhtpmag3.shtml
your best bet is to download the dynojet viewer from the above website and take a 3 1/2" floppy to your next dyne session. They should be able to save the file for your runs which you can later view on the program.
You can change all kinds of factors, like the correction (STD, SAE, ACTUAL, EEC, DIN), the smoothing factor (1-5), the display values, etc. You can save your runs from different days/mod conditions and "overlay them to really compare the curves (not just the old "useless" peak number comparisons).
It's really cool for a free program and makes you realize how easy it is for tuners/performance shops to "fudge" the numbers if they so choose. Just changing the smoothing factor alone can have quite an affect on the peak numbers (which, personally, I think are very poor to ever report. Too many things can happen like spikes caused at the end of a run due to hitting the rev limiter).
<end quote>
11-08-2002, 01:04 AM
#7
Happy CL-S Pilot
EricL... Impressive as usual 
Running the numbers:
Dyno #1: T=78.80 RH=65% P=29.27
Dyno #2: T=73.40 RH=57% P=29.18
Dyno #1: VPC=0.67 PD=28.60 >>>> CF=1.029
Dyno #2: VPC=0.44 PD=28.74 >>>> CF=1.015
Now ...the dyno read for run#1 54% RH and 45% RH for run #2
Asusming all other Temp and PA is the same.
Dyno #1: VPC=0.57 PD=28.70 >>>> CF=1.024
Dyno #2: VPC=0.33 PD=28.85 >>>> CF=1.010
looking from the table for each 0.25 PSI there is 1% difference
Therefore, the numbers should be higher by 0.5% or 1-2 HP only!
Running the numbers:
Dyno #1: T=78.80 RH=65% P=29.27
Dyno #2: T=73.40 RH=57% P=29.18
Dyno #1: VPC=0.67 PD=28.60 >>>> CF=1.029
Dyno #2: VPC=0.44 PD=28.74 >>>> CF=1.015
Now ...the dyno read for run#1 54% RH and 45% RH for run #2
Asusming all other Temp and PA is the same.
Dyno #1: VPC=0.57 PD=28.70 >>>> CF=1.024
Dyno #2: VPC=0.33 PD=28.85 >>>> CF=1.010
looking from the table for each 0.25 PSI there is 1% difference
Therefore, the numbers should be higher by 0.5% or 1-2 HP only!
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11-08-2002, 04:00 PM
#9
Got BOOST????
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Thanks for the research boys. I'm not gonna call this guy. I was curious what my HP was. seems kind low, that's all i wanted to know.
11-11-2002, 03:45 PM
#17
Got BOOST????
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I spoke to the owner about five min. ago. he said it should have been done in 3rd and he will give me a discount when i get it done. WTF, is he out of his mind!!!! He should do it for FREE cause he fucked up. Fucking Mustang Magic. Don't go there, fucking A-holes. A discout for his fuck up. He told me that i should have know better. Ur the freaking experts with the dyno, u should know this shit. sorry for venting boys.
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