IllusionalTA
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What do you guy's think? it was 91.4 deg. and 30.03hg on the barometer according to the dj's weather station.. I think the map could use some work.. but waiting for they're a/f meter to get fixed..
Got my 04 LE Dynoed
- Thread starter IllusionalTA
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IllusionalTA
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btw.. sorry for the image size.. lost my photoshop..
Johnnycheese
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Numbers are numbers. every builder I know used STD. the bottom line is apples to apples.
the numbers are little high and curve choppy due to the back wheel hop on the drum
Well our Pipercross filters are being tested by several AMA teams right now and everyone is showing SAE numbers in and SAE out which are way more vallid.
Maybe the dyno operator should have set-up the run a little better so there was no wheel hop its pretty easy to do. I guess some people get what they pay for........and tuning is pretty simple stuff.
Johnnycheese
Registered
like I said numbers are numbers.
sae in sae out is the same as std in and std out.
apples to apples
sae in sae out is the same as std in and std out.
apples to apples
Some good info from another site I frequent for those that need a better understanding of SAE and Standard. Good info.
Dyno Correction Factor and Relative Horsepower
So what's all this correction factor stuff anyway??
The horsepower and torque available from a normally aspirated internal combustion engine are dependent upon the density of the air... higher density means more oxygen molecules and more power... lower density means less oxygen and less power.
The relative horsepower, and the dyno correction factor, allow mathematical calculation of the affects of air density on the wide-open-throttle horsepower and torque. The dyno correction factor is simply the mathematical reciprocal of the relative horsepower value.
What's it good for?
One common use of the dyno correction factor is to standardize the horsepower and torque readings, so that the effects of the ambient temperature and pressure are removed from the readings. By using the dyno correction factor, power and torque readings can be directly compared to the readings taken on some other day, or even taken at some other altitude.
That is, the corrected readings are the same as the result that you would get by taking the car (or engine) to a certain temperature controlled, humidity controlled, pressure controlled dyno shop where they measure "standard" power, based on the carefully controlled temperature, humidity and pressure.
If you take your car to the dyno on a cold day at low altitude, it will make a lot of power. And if you take exactly the same car back to the same dyno on a hot day, it will make less power. But if you take the exact same car to the "standard" dyno (where the temperature, humidity and pressure are all carefully controlled) on those different days, it will always make exactly the same power.
Sometimes you may want to know how much power you are really making on that specific day due to the temperature, humidity and pressure on that day; in that case, you should look at the uncorrected power readings.
But when you want to see how much more power you have solely due to the new headers, or the new cam, then you will find that the corrected power is more useful, since it removes the effects of the temperature, humidity and atmospheric pressure and just shows you how much more (or less) power you have than in your previous tests.
There is no "right" answer... it's simply a matter of how you want to use the information.
If you want to know whether you are going to burn up the tranny with too much power on a cool, humid day, then go to the dyno and look at uncorrected power to see how exactly much power you have under these conditions.
But if you want to compare the effects due to modifications, or you want to compare several different cars at different times, then the corrected readings of the "standard" dyno will be more useful.
How's it calculated?
The Society of Automotive Engineers (SAE) has created a standard method for correcting horsepower and torque readings so that they will seem as if the readings had all been taken at the same "standard" test cell where the air pressure, humidity and air temperature are held constant.
The equation for the dyno correction factor given in SAE J1349 JUN90, converted to pressure in mb, is:
where: cf = the dyno correction factor
Pd = the pressure of the dry air, mb
Tc = ambient temperature, deg C
The pressure of the dry air Pd, is found by subtracting the vapor pressure Pv from the actual air pressure. For more information about pressures and calculation of the vapor pressure, see Air Density and Density Altitude.
The relative horsepower is simply the mathematical reciprocal of the correction factor.
Horsepower and Torque:
Power is the rate at which work is done. When the engine torque is turning the crankshaft and power is being delivered, the resulting horsepower may be expressed as:
which can be simplified as
where: hp = horsepower, hp
t = torque, ft-lbs
rpm = engine speed, revolutions per minute
This is a great formula. Basically it says that if you can keep the same amount of torque, then the more rpm you can turn, the more horsepower you get!
Dyno Correction Factor and Relative Horsepower
So what's all this correction factor stuff anyway??
The horsepower and torque available from a normally aspirated internal combustion engine are dependent upon the density of the air... higher density means more oxygen molecules and more power... lower density means less oxygen and less power.
The relative horsepower, and the dyno correction factor, allow mathematical calculation of the affects of air density on the wide-open-throttle horsepower and torque. The dyno correction factor is simply the mathematical reciprocal of the relative horsepower value.
What's it good for?
One common use of the dyno correction factor is to standardize the horsepower and torque readings, so that the effects of the ambient temperature and pressure are removed from the readings. By using the dyno correction factor, power and torque readings can be directly compared to the readings taken on some other day, or even taken at some other altitude.
That is, the corrected readings are the same as the result that you would get by taking the car (or engine) to a certain temperature controlled, humidity controlled, pressure controlled dyno shop where they measure "standard" power, based on the carefully controlled temperature, humidity and pressure.
If you take your car to the dyno on a cold day at low altitude, it will make a lot of power. And if you take exactly the same car back to the same dyno on a hot day, it will make less power. But if you take the exact same car to the "standard" dyno (where the temperature, humidity and pressure are all carefully controlled) on those different days, it will always make exactly the same power.
Sometimes you may want to know how much power you are really making on that specific day due to the temperature, humidity and pressure on that day; in that case, you should look at the uncorrected power readings.
But when you want to see how much more power you have solely due to the new headers, or the new cam, then you will find that the corrected power is more useful, since it removes the effects of the temperature, humidity and atmospheric pressure and just shows you how much more (or less) power you have than in your previous tests.
There is no "right" answer... it's simply a matter of how you want to use the information.
If you want to know whether you are going to burn up the tranny with too much power on a cool, humid day, then go to the dyno and look at uncorrected power to see how exactly much power you have under these conditions.
But if you want to compare the effects due to modifications, or you want to compare several different cars at different times, then the corrected readings of the "standard" dyno will be more useful.
How's it calculated?
The Society of Automotive Engineers (SAE) has created a standard method for correcting horsepower and torque readings so that they will seem as if the readings had all been taken at the same "standard" test cell where the air pressure, humidity and air temperature are held constant.
The equation for the dyno correction factor given in SAE J1349 JUN90, converted to pressure in mb, is:
where: cf = the dyno correction factor
Pd = the pressure of the dry air, mb
Tc = ambient temperature, deg C
The pressure of the dry air Pd, is found by subtracting the vapor pressure Pv from the actual air pressure. For more information about pressures and calculation of the vapor pressure, see Air Density and Density Altitude.
The relative horsepower is simply the mathematical reciprocal of the correction factor.
Horsepower and Torque:
Power is the rate at which work is done. When the engine torque is turning the crankshaft and power is being delivered, the resulting horsepower may be expressed as:
which can be simplified as
where: hp = horsepower, hp
t = torque, ft-lbs
rpm = engine speed, revolutions per minute
This is a great formula. Basically it says that if you can keep the same amount of torque, then the more rpm you can turn, the more horsepower you get!
IllusionalTA
Registered
Well either way.. If i continue to use the std. correction factor's.. for my own personal use.. what's the diff? the sae was only 3 off from the std which he had already printed for me.. I'm not really worried.... I was just curious where i was at.. Now to find that missing power..
IllusionalTA
Registered
fwiw.. brock uses std correction as well for his chart's.. Johnnycheese, pm sent..
Johnnycheese
Registered
the biggest problem with the DYNOJUNK dyno is the weather station. 3 yrs after I had maine I FIXED it MYSELF. NO HELP FROM DYNOJUNK. all they said is it is calibrated.
Yeah right if I was 780 feet below sealevel
I fixed it and read correctly now. 98% dynos don't so this is why I say apples to apples.
the one boy on this site that said his slip ons made 173hp with a graph to back it..... well ElPaso Tx is not 9K above sealevel and that was the SEA number
Conditions is the key to getting real readings
Hey GPW have you checked yours???
I know for a Fact Motorheads is off reads about 3% too much
Yeah right if I was 780 feet below sealevel
I fixed it and read correctly now. 98% dynos don't so this is why I say apples to apples.
the one boy on this site that said his slip ons made 173hp with a graph to back it..... well ElPaso Tx is not 9K above sealevel and that was the SEA number
Conditions is the key to getting real readings
Hey GPW have you checked yours???
I know for a Fact Motorheads is off reads about 3% too much
not just weather station issues but also air quality issues... a few pulls and the ventilation systems just can't handle it....
btw.. who care about hp numbers torque is the only thing that's measured... hp is just a calc from torque.... lol
btw.. who care about hp numbers torque is the only thing that's measured... hp is just a calc from torque.... lol
I have, we are at 275 feet above sea level and it reads 275...other than the O2 sensor having to be changed from race fuel, no issues yet. I also service the crap out of my machine and run new a new o2 filter every custom map.(Johnnycheese @ Jul. 10 2007,20) the biggest problem with the DYNOJUNK dyno is the weather station. 3 yrs after I had maine I FIXED it MYSELF. NO HELP FROM DYNOJUNK. all they said is it is calibrated.
Yeah right if I was 780 feet below sealevel
I fixed it and read correctly now. 98% dynos don't so this is why I say apples to apples.
the one boy on this site that said his slip ons made 173hp with a graph to back it..... well ElPaso Tx is not 9K above sealevel and that was the SEA number
Conditions is the key to getting real readings
Hey GPW have you checked yours???
I know for a Fact Motorheads is off reads about 3% too much
Is your weather station inside your dyno?
IllusionalTA
Registered
Spoke w/ brock's today as the result's aren't typical, they told me that 9 out of 10 time's it's usually clogged/dirty injector's.. Although the pull was strong i feel i have some left.. So i'll throw a gallon of MR9 in and try to clean up the injector's and see how it does.. afterwards... If it don't work.. I'm gonna put on some slip on's and enjoy 173whp..
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