SAE vs STD
03-22-2007, 09:23 AM
#1
SAE vs STD I know that STD numbers are usually a little higher that SAE. What makes either reading better than the other? Which correction factors go into each and why is there a difference? I have just been curious of these things. Why are SAE numbers lower and why are they more realistic that STD? Just a few questions......
03-22-2007, 10:15 AM
#2
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STD is what it actully put out that day with the air/humidty/ ect.
SAE is a standarized atmosphere condition so as to compare output regardless of exact current conditions. otherwise the same car would put out different numbers every day pretty much.
i believe it corrects to a 70* day with relitively low humidty
SAE is a standarized atmosphere condition so as to compare output regardless of exact current conditions. otherwise the same car would put out different numbers every day pretty much.
i believe it corrects to a 70* day with relitively low humidty
03-22-2007, 10:44 AM
#3
No, STD is a different correction constants (like temp, humidity, pressure). Uncorrected is what the car actually put down. SAE is just corrected to different constants. My last dyno, STD was about 10 hp and 10 ftlbs more than SAE in 68ºF air, 29.25 inHg, and 26% humidity.
03-22-2007, 12:29 PM
#6
Some people confuse or refer to STD as uncorrected but when I hear standard I think about the OLD STANDARD SAE J607 correction. STD and SAE are two of SEVERAL correction factors. They are the most common that we hear about and both are SAE corrections, just different versions or formulas.
UNCORRECTED= what the engine made right then on that air.
J607 std= 60°F, 0% humidity, 29.92 baro. (std)
J1349 std = 77°F, 0% humidity, 29.234 baro. (sae)
J1995 std= 77°F, 0% humidity, 29.53 baro.
DIN std= 68°F, 0% humidity, 29.92 baro.
JIS std = 77°F, 0% humidity 29.234 baro. and different eff. cal.
ECE std= 77°F, 0% humidity, 29.234 baro. (like J1349 but with NO mechanical efficiency cal.)
So be careful with all the STD's out there..
UNCORRECTED= what the engine made right then on that air.
J607 std= 60°F, 0% humidity, 29.92 baro. (std)
J1349 std = 77°F, 0% humidity, 29.234 baro. (sae)
J1995 std= 77°F, 0% humidity, 29.53 baro.
DIN std= 68°F, 0% humidity, 29.92 baro.
JIS std = 77°F, 0% humidity 29.234 baro. and different eff. cal.
ECE std= 77°F, 0% humidity, 29.234 baro. (like J1349 but with NO mechanical efficiency cal.)
So be careful with all the STD's out there..
Last edited by DynoDR; 03-22-2007 at 12:36 PM.
03-22-2007, 02:29 PM
#7
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Originally Posted by DynoDR
Some people confuse or refer to STD as uncorrected but when I hear standard I think about the OLD STANDARD SAE J607 correction. STD and SAE are two of SEVERAL correction factors. They are the most common that we hear about and both are SAE corrections, just different versions or formulas.
UNCORRECTED= what the engine made right then on that air.
J607 std= 60°F, 0% humidity, 29.92 baro. (std)
J1349 std = 77°F, 0% humidity, 29.234 baro. (sae)
J1995 std= 77°F, 0% humidity, 29.53 baro.
DIN std= 68°F, 0% humidity, 29.92 baro.
JIS std = 77°F, 0% humidity 29.234 baro. and different eff. cal.
ECE std= 77°F, 0% humidity, 29.234 baro. (like J1349 but with NO mechanical efficiency cal.)
So be careful with all the STD's out there..
UNCORRECTED= what the engine made right then on that air.
J607 std= 60°F, 0% humidity, 29.92 baro. (std)
J1349 std = 77°F, 0% humidity, 29.234 baro. (sae)
J1995 std= 77°F, 0% humidity, 29.53 baro.
DIN std= 68°F, 0% humidity, 29.92 baro.
JIS std = 77°F, 0% humidity 29.234 baro. and different eff. cal.
ECE std= 77°F, 0% humidity, 29.234 baro. (like J1349 but with NO mechanical efficiency cal.)
So be careful with all the STD's out there..
STD CF. usually shows higher numbers 2-3%
peace
