Evolved Member
Both AWD and 2WD dynojets offer SAE correction (as well as DIN correction but that's another story) To see if the numbers are corrected or uncorrected, look at the graph. If the axis label says "SAE Corrected HP and Torque" then they are corrected for temp, humidity and altitude. If they say "Actual HP and torque", they are not tweaked at all and represent the actual Dynojet output the car put out under those conditions.
Under standard conditions (around 70F, sea level with moderate humidity), the SAE correction factor should be close to 1.00. This means that uncorrected and SAE corrected numbers will be very close to each other. The further you get away from these standard conditions, the bigger the differential between actual hp and paper hp. In some conditions, especially when high altitude is involved (say in Denver, for instance), the correction factor could get as high as 1.25 (!) which means that becomes increasingly important to understand what your car is actually putting down in the real world.
Shiv
Under standard conditions (around 70F, sea level with moderate humidity), the SAE correction factor should be close to 1.00. This means that uncorrected and SAE corrected numbers will be very close to each other. The further you get away from these standard conditions, the bigger the differential between actual hp and paper hp. In some conditions, especially when high altitude is involved (say in Denver, for instance), the correction factor could get as high as 1.25 (!) which means that becomes increasingly important to understand what your car is actually putting down in the real world.
Shiv
Thanks shiv, that is good info to have and thanks for sharing your knowledge.
Now to only find out how AA is obtaining these variables that usually come from the DynoJet brand weather station? Can you just look them up in the newspaper and enter in the data manually? Is that less accurate than having the weather station?
Now to only find out how AA is obtaining these variables that usually come from the DynoJet brand weather station? Can you just look them up in the newspaper and enter in the data manually? Is that less accurate than having the weather station?
Evolved Member
Quote:
Originally posted by sir lurks alot
Thanks shiv, that is good info to have and thanks for sharing your knowledge.
Now to only find out how AA is obtaining these variables that usually come from the DynoJet brand weather station? Can you just look them up in the newspaper and enter in the data manually? Is that less accurate than having the weather station?
Probably best to call up AA and ask them to pull up your dyno results on their computer. Then all they have to do is pick "display uncorrected power" from the menu bar and the numbers will change to actuals. Divide corrected by uncorrected and you can gome up with the correction factor. Originally posted by sir lurks alot
Thanks shiv, that is good info to have and thanks for sharing your knowledge.
Now to only find out how AA is obtaining these variables that usually come from the DynoJet brand weather station? Can you just look them up in the newspaper and enter in the data manually? Is that less accurate than having the weather station?
shiv
Evolving Member
Quote:
Originally posted by sir lurks alot
I was under the impression that there were no SAE standards to measure for AWD?
The SAE standard for measuring engine power is J1349. The "correction factor" is meant to adjust the measured power to "standard conditions" and is explained at http://wahiduddin.net/calc/cf.htm. However, the SAE correction factor doesn't account for the fact that turbocharged engines can easily maintain whatever absolute manifold air pressure the ECU desires, regardles of the ambient atmospheric pressure. So when measurements are taken when the atmospheric pressure is low, the resulting correction factor will overstate the engines performance under standard conditions. Some people have proposed modifications to the SAE correction factor to make it more accurate for turbocharged engines. An example can be found at http://home.austin.rr.com/turbolexus..._Dyno_Calc.htm.Originally posted by sir lurks alot
I was under the impression that there were no SAE standards to measure for AWD?
I also have a question. In my book, a "tune" is safe if and only if there is no knock. Exactly what was done during these dyno sessions to determine whether any knock occured?
EvoM Guru
The shop is practically in a desert environment, I am sure in the early morning it was 60 and dry, by the afternoon it was probably more likely in the 90's.
This is just one more reason why I believe much of Shiv's reported test data is inaccurate. I have been to his shop (it's no much), but all you have to do is look at the weather reports online for his location to see that they have very large temp changes throughout the day/evening. Yet he uses no correction factor, he says that he will simply report the conditions of each run, I haven't seen any of his posted data showing environmental conditions have you?
His posted theories also say that high humidity and Temp will actually allow a turbo car to produce more HP, which is wrong for so many reasons I don’t even know where to start. All I am going say is that any one that lives in an environment where you see high heat/humidity (like myself) can tell you that turbo car’s loose a great deal of power in these conditions, more so than an NA car. If anything I have found the dyno correction factors do not adequately compensate for environmental conditions when referring to a turbo car. While you can obviously use these factors to make your HP numbers look higher or lower if desired, when used consistently and honestly they help provide more accurate test data when comparing car’s in different times/location’s.
And that whole business of switching to third gear, first off every other dyno I have used actually shows the engine making more power in the higher gears, and turbo engines actually do make more power under higher load. Other dynos correct for higher speed frictional loses his apparently does not, confused yet? You’re just not trying hard enough.
SAE correction factors are constant, they don’t change from one dyno to another, they are there to try and help remove inconsistencies from one time/location to another, with turbo car’s IMO they do not adequately compensate for conditions, but it’s better than nothing. Not using any correction factors and then not recording all environmental/test conditions just makes your data even more skewed. So which of his data was done in what gear, what were the environmental conditions? That coupled with several issues I have regarding this dyno make comparing his data with any other system or real world situation very sketchy at best.
That’s my 2 cents
This is just one more reason why I believe much of Shiv's reported test data is inaccurate. I have been to his shop (it's no much), but all you have to do is look at the weather reports online for his location to see that they have very large temp changes throughout the day/evening. Yet he uses no correction factor, he says that he will simply report the conditions of each run, I haven't seen any of his posted data showing environmental conditions have you?
His posted theories also say that high humidity and Temp will actually allow a turbo car to produce more HP, which is wrong for so many reasons I don’t even know where to start. All I am going say is that any one that lives in an environment where you see high heat/humidity (like myself) can tell you that turbo car’s loose a great deal of power in these conditions, more so than an NA car. If anything I have found the dyno correction factors do not adequately compensate for environmental conditions when referring to a turbo car. While you can obviously use these factors to make your HP numbers look higher or lower if desired, when used consistently and honestly they help provide more accurate test data when comparing car’s in different times/location’s.
And that whole business of switching to third gear, first off every other dyno I have used actually shows the engine making more power in the higher gears, and turbo engines actually do make more power under higher load. Other dynos correct for higher speed frictional loses his apparently does not, confused yet? You’re just not trying hard enough.
SAE correction factors are constant, they don’t change from one dyno to another, they are there to try and help remove inconsistencies from one time/location to another, with turbo car’s IMO they do not adequately compensate for conditions, but it’s better than nothing. Not using any correction factors and then not recording all environmental/test conditions just makes your data even more skewed. So which of his data was done in what gear, what were the environmental conditions? That coupled with several issues I have regarding this dyno make comparing his data with any other system or real world situation very sketchy at best.
That’s my 2 cents
Great Stuff!
Quote:
Originally posted by Señor Info
The SAE standard for measuring engine power is J1349. The "correction factor" is meant to adjust the measured power to "standard conditions" and is explained at http://wahiduddin.net/calc/cf.htm. However, the SAE correction factor doesn't account for the fact that turbocharged engines can easily maintain whatever absolute manifold air pressure the ECU desires, regardles of the ambient atmospheric pressure. So when measurements are taken when the atmospheric pressure is low, the resulting correction factor will overstate the engines performance under standard conditions. Some people have proposed modifications to the SAE correction factor to make it more accurate for turbocharged engines. An example can be found at http://home.austin.rr.com/turbolexus..._Dyno_Calc.htm.
I also have a question. In my book, a "tune" is safe if and only if there is no knock. Exactly what was done during these dyno sessions to determine whether any knock occured?
So do you recommend using an obd logger like pocketlogger that can read timing to check for knock? Or what instrument should one use?Originally posted by Señor Info
The SAE standard for measuring engine power is J1349. The "correction factor" is meant to adjust the measured power to "standard conditions" and is explained at http://wahiduddin.net/calc/cf.htm. However, the SAE correction factor doesn't account for the fact that turbocharged engines can easily maintain whatever absolute manifold air pressure the ECU desires, regardles of the ambient atmospheric pressure. So when measurements are taken when the atmospheric pressure is low, the resulting correction factor will overstate the engines performance under standard conditions. Some people have proposed modifications to the SAE correction factor to make it more accurate for turbocharged engines. An example can be found at http://home.austin.rr.com/turbolexus..._Dyno_Calc.htm.
I also have a question. In my book, a "tune" is safe if and only if there is no knock. Exactly what was done during these dyno sessions to determine whether any knock occured?
I think you may be getting confused with all the topics floating around in this thread. The 60 and dry was the day that Shiv came to AA in Maryland to custom tune some exede units.
Quote:
Originally posted by SILVER SURFER
The shop is practically in a desert environment, I am sure in the early morning it was 60 and dry, by the afternoon it was probably more likely in the 90's.
This is just one more reason why I believe much of Shiv's reported test data is inaccurate. I have been to his shop (it's no much), but all you have to do is look at the weather reports online for his location to see that they have very large temp changes throughout the day/evening. Yet he uses no correction factor, he says that he will simply report the conditions of each run, I haven't seen any of his posted data showing environmental conditions have you?
His posted theories also say that high humidity and Temp will actually allow a turbo car to produce more HP, which is wrong for so many reasons I don’t even know where to start. All I am going say is that any one that lives in an environment where you see high heat/humidity (like myself) can tell you that turbo car’s loose a great deal of power in these conditions, more so than an NA car. If anything I have found the dyno correction factors do not adequately compensate for environmental conditions when referring to a turbo car. While you can obviously use these factors to make your HP numbers look higher or lower if desired, when used consistently and honestly they help provide more accurate test data when comparing car’s in different times/location’s.
And that whole business of switching to third gear, first off every other dyno I have used actually shows the engine making more power in the higher gears, and turbo engines actually do make more power under higher load. Other dynos correct for higher speed frictional loses his apparently does not, confused yet? You’re just not trying hard enough.
SAE correction factors are constant, they don’t change from one dyno to another, they are there to try and help remove inconsistencies from one time/location to another, with turbo car’s IMO they do not adequately compensate for conditions, but it’s better than nothing. Not using any correction factors and then not recording all environmental/test conditions just makes your data even more skewed. So which of his data was done in what gear, what were the environmental conditions? That coupled with several issues I have regarding this dyno make comparing his data with any other system or real world situation very sketchy at best.
That’s my 2 cents
Originally posted by SILVER SURFER
The shop is practically in a desert environment, I am sure in the early morning it was 60 and dry, by the afternoon it was probably more likely in the 90's.
This is just one more reason why I believe much of Shiv's reported test data is inaccurate. I have been to his shop (it's no much), but all you have to do is look at the weather reports online for his location to see that they have very large temp changes throughout the day/evening. Yet he uses no correction factor, he says that he will simply report the conditions of each run, I haven't seen any of his posted data showing environmental conditions have you?
His posted theories also say that high humidity and Temp will actually allow a turbo car to produce more HP, which is wrong for so many reasons I don’t even know where to start. All I am going say is that any one that lives in an environment where you see high heat/humidity (like myself) can tell you that turbo car’s loose a great deal of power in these conditions, more so than an NA car. If anything I have found the dyno correction factors do not adequately compensate for environmental conditions when referring to a turbo car. While you can obviously use these factors to make your HP numbers look higher or lower if desired, when used consistently and honestly they help provide more accurate test data when comparing car’s in different times/location’s.
And that whole business of switching to third gear, first off every other dyno I have used actually shows the engine making more power in the higher gears, and turbo engines actually do make more power under higher load. Other dynos correct for higher speed frictional loses his apparently does not, confused yet? You’re just not trying hard enough.
SAE correction factors are constant, they don’t change from one dyno to another, they are there to try and help remove inconsistencies from one time/location to another, with turbo car’s IMO they do not adequately compensate for conditions, but it’s better than nothing. Not using any correction factors and then not recording all environmental/test conditions just makes your data even more skewed. So which of his data was done in what gear, what were the environmental conditions? That coupled with several issues I have regarding this dyno make comparing his data with any other system or real world situation very sketchy at best.
That’s my 2 cents
Evolved Member
Quote:
Originally posted by SILVER SURFER
The shop is practically in a desert environment, I am sure in the early morning it was 60 and dry, by the afternoon it was probably more likely in the 90's.
This is just one more reason why I believe much of Shiv's reported test data is inaccurate. I have been to his shop (it's no much), but all you have to do is look at the weather reports online for his location to see that they have very large temp changes throughout the day/evening. Yet he uses no correction factor, he says that he will simply report the conditions of each run, I haven't seen any of his posted data showing environmental conditions have you?
His posted theories also say that high humidity and Temp will actually allow a turbo car to produce more HP, which is wrong for so many reasons I don’t even know where to start. All I am going say is that any one that lives in an environment where you see high heat/humidity (like myself) can tell you that turbo car’s loose a great deal of power in these conditions, more so than an NA car. If anything I have found the dyno correction factors do not adequately compensate for environmental conditions when referring to a turbo car. While you can obviously use these factors to make your HP numbers look higher or lower if desired, when used consistently and honestly they help provide more accurate test data when comparing car’s in different times/location’s.
And that whole business of switching to third gear, first off every other dyno I have used actually shows the engine making more power in the higher gears, and turbo engines actually do make more power under higher load. Other dynos correct for higher speed frictional loses his apparently does not, confused yet? You’re just not trying hard enough.
SAE correction factors are constant, they don’t change from one dyno to another, they are there to try and help remove inconsistencies from one time/location to another, with turbo car’s IMO they do not adequately compensate for conditions, but it’s better than nothing. Not using any correction factors and then not recording all environmental/test conditions just makes your data even more skewed. So which of his data was done in what gear, what were the environmental conditions? That coupled with several issues I have regarding this dyno make comparing his data with any other system or real world situation very sketchy at best.
That’s my 2 cents
Just about everything you have said is wrong. We do use corrections for temp, humidity and baro. If you ever saw our dyno operate, you'd see that it reads baro, ambient temp and air inlet temp and compensates accordingly. Originally posted by SILVER SURFER
The shop is practically in a desert environment, I am sure in the early morning it was 60 and dry, by the afternoon it was probably more likely in the 90's.
This is just one more reason why I believe much of Shiv's reported test data is inaccurate. I have been to his shop (it's no much), but all you have to do is look at the weather reports online for his location to see that they have very large temp changes throughout the day/evening. Yet he uses no correction factor, he says that he will simply report the conditions of each run, I haven't seen any of his posted data showing environmental conditions have you?
His posted theories also say that high humidity and Temp will actually allow a turbo car to produce more HP, which is wrong for so many reasons I don’t even know where to start. All I am going say is that any one that lives in an environment where you see high heat/humidity (like myself) can tell you that turbo car’s loose a great deal of power in these conditions, more so than an NA car. If anything I have found the dyno correction factors do not adequately compensate for environmental conditions when referring to a turbo car. While you can obviously use these factors to make your HP numbers look higher or lower if desired, when used consistently and honestly they help provide more accurate test data when comparing car’s in different times/location’s.
And that whole business of switching to third gear, first off every other dyno I have used actually shows the engine making more power in the higher gears, and turbo engines actually do make more power under higher load. Other dynos correct for higher speed frictional loses his apparently does not, confused yet? You’re just not trying hard enough.
SAE correction factors are constant, they don’t change from one dyno to another, they are there to try and help remove inconsistencies from one time/location to another, with turbo car’s IMO they do not adequately compensate for conditions, but it’s better than nothing. Not using any correction factors and then not recording all environmental/test conditions just makes your data even more skewed. So which of his data was done in what gear, what were the environmental conditions? That coupled with several issues I have regarding this dyno make comparing his data with any other system or real world situation very sketchy at best.
That’s my 2 cents
Also, contrary to what you may believe, dyno testing in 4th gear, instead of 3rd gear, on a proper load bearing dyno, does result in less power to the wheels due to the extra frictional losses involved in spinning the wheels to ~120mph instead of ~90mph.
And what you didn't undestand with regards to my comments about high temps and humidity is that dynos can sometimes overcorrect for such conditions. This is because they rely on a one-size-fits all correction factor that it applies to NA and turbo cars alike. Clearly, this is not ideal. If you had a dyno and actually used it on a day-to-day basis, you'd see all this issues instead of trying to propogate nonsense and misinformation.
shiv
Evolved Member
i can understand everyone has there own opinion with regards to facts.....
but one thing stands out more obvious than anything.......
nobody backs up there opinions with facts like shiv does.....
the man just oozes with knowledge and experience.....
and the rest of us just go on hear say and assumptions...
but one thing stands out more obvious than anything.......
nobody backs up there opinions with facts like shiv does.....
the man just oozes with knowledge and experience.....
and the rest of us just go on hear say and assumptions...
Evolved Member
Quote:
Originally posted by heshamnaim
the man just oozes with knowledge and experience.....
eewwww! Originally posted by heshamnaim
the man just oozes with knowledge and experience.....
-- DavidV
Evolved Member
Quote:
Originally posted by DavidV@WORKS
eewwww!
-- DavidV
Ya and you guys pay this guy to tune your car Originally posted by DavidV@WORKS
eewwww!
-- DavidV
Evolved Member
Quote:
Originally posted by Eric Lyublinsky
Ya and you guys pay this guy to tune your car
I don't tune cars... but then again, I don't ooze either. Originally posted by Eric Lyublinsky
Ya and you guys pay this guy to tune your car
-- DavidV
EvoM Guru
Shiv writes:
From Shiv's web site:
Shiv writes:
From Shiv's web site:
Look, I am not trying to say that the correction methods are perfect or that one dyno is actually better than another. It's more that your system is so far out there from what every one else in the US is using, your results are not comparable. If no one else can or will verify your test data, it has little value IMO. If you were just using it to promote your own stuff, I down think we would be giving you such a hard time about it. But you and your minions are constantly attacking other's with test data that is obviously so flawed I could drive a truck through the holes in it.
Why didn't you just say something "Because I the great Shiv said so, now go away you little **** ant!"
Can you show me on this, or for that matter any of your posted plots where enviromental conditions are indicated?
Quote:
Just about everything you have said is wrong. We do use corrections for temp, humidity and baro. If you ever saw our dyno operate, you'd see that it reads baro, ambient temp and air inlet temp and compensates accordingly.
Oh really, so I guess this little didy on your web site is BS then?Just about everything you have said is wrong. We do use corrections for temp, humidity and baro. If you ever saw our dyno operate, you'd see that it reads baro, ambient temp and air inlet temp and compensates accordingly.
From Shiv's web site:
Quote:
The Result
For this reason, all dynamometer results provided by Vishnu Performance Systems will be actual, as measured and "uncorrected." Since we (and our dynamometers) are located in the San Francisco Bay Area, there is no need for any altitude correction. Furthermore, since the dyno facilities are in-door, testing conditions are almost always just around room temperature. In the case where testing conditions differ dramatically, we will disclose such information. We feel these efforts will go a long way in ensuring that our claimed gains translate well into real-world performance.
The Result
For this reason, all dynamometer results provided by Vishnu Performance Systems will be actual, as measured and "uncorrected." Since we (and our dynamometers) are located in the San Francisco Bay Area, there is no need for any altitude correction. Furthermore, since the dyno facilities are in-door, testing conditions are almost always just around room temperature. In the case where testing conditions differ dramatically, we will disclose such information. We feel these efforts will go a long way in ensuring that our claimed gains translate well into real-world performance.
Shiv writes:
Quote:
And what you didn't undestand with regards to my comments about high temps and humidity is that dynos can sometimes overcorrect for such conditions. This is because they rely on a one-size-fits all correction factor that it applies to NA and turbo cars alike. Clearly, this is not ideal.
That's funny? that's not what this says:And what you didn't undestand with regards to my comments about high temps and humidity is that dynos can sometimes overcorrect for such conditions. This is because they rely on a one-size-fits all correction factor that it applies to NA and turbo cars alike. Clearly, this is not ideal.
From Shiv's web site:
Quote:
When humidity rises, the extra water content in the air charge actually acts as a passive cooler of sorts, lowering in-cylinder temperatures just enough to allow for a few more degrees of ignition advance without the presence of detonation. In other words, whatever engine output is lost through the reduction in oxygen content is gained (and then some) through a significant bump in thermal efficiency (caused by operating with more ignition advance). Voila-another improperly applied correction factor!
There's somthing oozing here alright.When humidity rises, the extra water content in the air charge actually acts as a passive cooler of sorts, lowering in-cylinder temperatures just enough to allow for a few more degrees of ignition advance without the presence of detonation. In other words, whatever engine output is lost through the reduction in oxygen content is gained (and then some) through a significant bump in thermal efficiency (caused by operating with more ignition advance). Voila-another improperly applied correction factor!
Look, I am not trying to say that the correction methods are perfect or that one dyno is actually better than another. It's more that your system is so far out there from what every one else in the US is using, your results are not comparable. If no one else can or will verify your test data, it has little value IMO. If you were just using it to promote your own stuff, I down think we would be giving you such a hard time about it. But you and your minions are constantly attacking other's with test data that is obviously so flawed I could drive a truck through the holes in it.
Quote:
If you had a dyno and actually used it on a day-to-day basis, you'd see all this issues instead of trying to propogate nonsense and misinformation.
Aw,, now that hurt If you had a dyno and actually used it on a day-to-day basis, you'd see all this issues instead of trying to propogate nonsense and misinformation.
Why didn't you just say something "Because I the great Shiv said so, now go away you little **** ant!" Can you show me on this, or for that matter any of your posted plots where enviromental conditions are indicated?
