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.

[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.

[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