CALC.POWER_RW, how does it work?

[NewV]

I'm assuming it makes a rudimentary calculation but mine is always 0. What else needs to be logged besides SAE.VSS or how do you use it?

Expression:
HP = gvmlb()*{SAE.VSS.mph}*dx({SAE.VSS.mph},6)/8226.63
is VALID


The calculation shown references gvmlb() which I'm assuming is gross vehicle pounds, where does it get that from?

Assuming my car actually has > 0 RWHP. :help2:

[Tordne]

The vehicle weight is entered with the VIN data in the Scan Tool. Go to the File->Enter VIN option and enter the vehicle weight. This will probably fix the problem for you.

[NewV]

The vehicle weight is entered with the VIN data in the Scan Tool. Go to the File->Enter VIN option and enter the vehicle weight. This will probably fix the problem for you.

Do you know if that needs to be setup before you log? I am able to enter it but it still shows 0. However I don't think I entered it prior to logging.

[Tordne]

I honestly haven't tried. It is a CALC PID so perhaps you can get away with adding/changing. Only way to know is to try :)

[joecar]

That pid gives a very rough estimate of instananeous rwhp...

The problem with it is that VSS is sampled at only 10 samples/second which isn't often enough to get an accurate calculation...

But if conditions are controlled and you accelerate smoothly, you can get a reasonable approximation.

Take a log accelerating WOT till you hit speed X mph...
Then take a log coasting down from X mph (on the same strech of road in the same direction), this produces a negative rwhp...

then go like this: peak_positive_rwhp - peak_negative_rwhp

(remember subtracting a negative number is like adding its absolute value)...

the result will be a number approximating fwhp; e.g. 275 - (-65) = 340

Of course this is all very rough and works better for some people than others.

[joecar]

Do you know if that needs to be setup before you log? I am able to enter it but it still shows 0. However I don't think I entered it prior to logging.It requires logging of VSS, and vehicle mass to be entered.

You may have to log again after enabling the calc pid.

[dc_justin]

Do you know if that needs to be setup before you log? I am able to enter it but it still shows 0. However I don't think I entered it prior to logging.

I've never had a problem selecting a calc pid after the log has been made, so long as the PID(s) it depends on were used during the log.

[Tordne]

This particular one uses an embeded function though. I'm not sure if that is expanded for each frame in the log or dynamically as the log is viewed.

[dc_justin]

This particular one uses an embeded function though. I'm not sure if that is expanded for each frame in the log or dynamically as the log is viewed.

I have it up in one of my logs right now. I can de-select it and reselect without a problem. Tried it on one that it was not selected on from the get-go and it worked as well. :cheers:

[NewV]

Ok, thx guys. It does not seem to work for me unless I had the weight entered prior to the log.

I'll need to try some WOT runs as Joe suggests. I hate when I have to do that :)

[5.7ute]

I have added this once before to see if it would work as well with no problems. Are you changing it through the Edit default customer settings or Edit log file information.

[NewV]

I have added this once before to see if it would work as well with no problems. Are you changing it through the Edit default customer settings or Edit log file information.

Excellent that does work. I was going throug the File->Enter VIN which did not work for me. The Edit->Log File Information option does work. :D