Logging data for Horse Power
Apr 12, 2009, 07:04 PM
#1
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How do I log horsepower?
Please confirm the best way to log data for determining my horse power?
1. Pull from all gears
2. Pull from a specific gear to redline
1. Pull from all gears
2. Pull from a specific gear to redline
Last edited by roberttonge; Apr 12, 2009 at 07:44 PM.
Apr 13, 2009, 06:09 PM
#3
Actually, the most commonly used gear (on a 5-speed at least) is 3rd gear. It gives fair resolution and doesn't require going over 80mph, which is the gear that almost all dyno shops tune with, occassionally doing a 4th gear pull afterward to check for any touchy areas.
If you're using Evoscan:
For JUST power logging you want to log the least amount possible for the best resolution. Log just your Speed and RPM (not 2 byte RPM, evoscan uses the standard RPM for its calculations). Start your 3rd gear pull on a flat surface at 3k rpm and keep it at wide open throttle until redline and let off the gas.
Be sure to edit the "Power/Torque Vehicle Settings" info to get the most accurate results possible. The "People Contents Weight" column does nothing (though its supposed to) so add your vehicle weight and occupants weight together and enter it in the "Factory Vehicle Weight" column. Go online and lookup your local weather for the Barometric pressure and ambient Air temps too, these make a big difference.
The "dyno correction factor" column does nothing either (though its supposed to).
Also, some might notice that the torque and HP curves do not cross at 5252 RPM like they are supposed to which means Hamish's calculations for the power section are slightly off anyhow so dont go bragging to your buddies that they are solid numbers lol.
Its best to use the EXACT same stretch of road each time to get the best A/B comparison logs.
If you're using Evoscan:
For JUST power logging you want to log the least amount possible for the best resolution. Log just your Speed and RPM (not 2 byte RPM, evoscan uses the standard RPM for its calculations). Start your 3rd gear pull on a flat surface at 3k rpm and keep it at wide open throttle until redline and let off the gas.
Be sure to edit the "Power/Torque Vehicle Settings" info to get the most accurate results possible. The "People Contents Weight" column does nothing (though its supposed to) so add your vehicle weight and occupants weight together and enter it in the "Factory Vehicle Weight" column. Go online and lookup your local weather for the Barometric pressure and ambient Air temps too, these make a big difference.
The "dyno correction factor" column does nothing either (though its supposed to).
Also, some might notice that the torque and HP curves do not cross at 5252 RPM like they are supposed to which means Hamish's calculations for the power section are slightly off anyhow so dont go bragging to your buddies that they are solid numbers lol.
Its best to use the EXACT same stretch of road each time to get the best A/B comparison logs.
Last edited by Jack_of_Trades; Apr 13, 2009 at 06:17 PM.
Apr 13, 2009, 06:47 PM
#4
Actually, the most commonly used gear (on a 5-speed at least) is 3rd gear. It gives fair resolution and doesn't require going over 80mph, which is the gear that almost all dyno shops tune with, occassionally doing a 4th gear pull afterward to check for any touchy areas.
If you're using Evoscan:
For JUST power logging you want to log the least amount possible for the best resolution. Log just your Speed and RPM (not 2 byte RPM, evoscan uses the standard RPM for its calculations). Start your 3rd gear pull on a flat surface at 3k rpm and keep it at wide open throttle until redline and let off the gas.
Be sure to edit the "Power/Torque Vehicle Settings" info to get the most accurate results possible. The "People Contents Weight" column does nothing (though its supposed to) so add your vehicle weight and occupants weight together and enter it in the "Factory Vehicle Weight" column. Go online and lookup your local weather for the Barometric pressure and ambient Air temps too, these make a big difference.
The "dyno correction factor" column does nothing either (though its supposed to).
Also, some might notice that the torque and HP curves do not cross at 5252 RPM like they are supposed to which means Hamish's calculations for the power section are slightly off anyhow so dont go bragging to your buddies that they are solid numbers lol.
Its best to use the EXACT same stretch of road each time to get the best A/B comparison logs.
If you're using Evoscan:
For JUST power logging you want to log the least amount possible for the best resolution. Log just your Speed and RPM (not 2 byte RPM, evoscan uses the standard RPM for its calculations). Start your 3rd gear pull on a flat surface at 3k rpm and keep it at wide open throttle until redline and let off the gas.
Be sure to edit the "Power/Torque Vehicle Settings" info to get the most accurate results possible. The "People Contents Weight" column does nothing (though its supposed to) so add your vehicle weight and occupants weight together and enter it in the "Factory Vehicle Weight" column. Go online and lookup your local weather for the Barometric pressure and ambient Air temps too, these make a big difference.
The "dyno correction factor" column does nothing either (though its supposed to).
Also, some might notice that the torque and HP curves do not cross at 5252 RPM like they are supposed to which means Hamish's calculations for the power section are slightly off anyhow so dont go bragging to your buddies that they are solid numbers lol.
Its best to use the EXACT same stretch of road each time to get the best A/B comparison logs.
I have never got it to work reliably. Which version of Evoscan are you using and do you mind sharing your Evoscan data.xml?
TIA
Apr 14, 2009, 09:00 AM
#5
My method is 3rd gear so the end speeds aren't too crazy high. and to start with 3rd gear 2000rpm to 6000rpm, make sure your AFR and Knock is safe, then continue with some runs higher up to 7200rpm etc. keep dataitems logged to a minimum for maximum EvoScan resolution of datalogged items.
Apr 14, 2009, 03:42 PM
#6
Hamish, still gonna be able to give the power section a good "once over" before the next revision? I love the feature and use it very often but its just those few problem area's that I would be excited to see fixed.
- People Contents Weight
- Dyno Correction factor
- HP/TQ curves not crossing at 5252 RPM
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Apr 19, 2009, 06:57 PM
#10
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has anyone tested the accuracy of the evoscan dyno? assuming u get a flat piece of road, and account for the vehicle weight properly, how accurate is it really?
Apr 19, 2009, 09:54 PM
#12
In order for it to work, you need to highlight JUST the 3rd gear pull, right up to the point where you let off the gas. Then do your pull. You just need to log SPEED and RPM. Obviously, you gotta set up the "Vehicle Settings" by choosing your vehicle type from the dropdown list, adding the air temperature and barometric pressure.
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