Logger Help: WHP and Torque

ev8siv3 · **Joined:** Fri Mar 24, 2006 7:14 pm **Posts:** 768

I haven't messed with much of the XML on the new logger but I have this working on my EcuEdit logger. Perhaps you guys could help with this calculation parameter. I tested it last night and it didn't work for me.

Code:

                <parameter id="P205" name="WHP"
                           desc="Approximate Wheel Horsepower">
                    <depends>
                        <ref parameter="P12"/> <!-- MAF-->
                    </depends>
                    <conversions>
                        <conversion units="whp" expr="[P12]*1.064" format="0.00"/>
                    </conversions>
                </parameter>

                <parameter id="P206" name="Torque"
                           desc="Approximate Wheel Torque">
                    <depends>
                        <ref parameter="P8"/> <!-- Engine Speed -->
                        <ref parameter="P205"/> <!-- WHP-->
                    </depends>
                    <conversions>
                        <conversion units="lb-ft" expr="([P205]*5252)/[P8]" format="0.00"/>
                    </conversions>
                </parameter>

kascade · **Posted:** Fri Apr 27, 2007 11:23 pm

try removing the square brackets from around the parameter variables in the expressions. you only need the square brackets when specifying which conversion of a parameter to use. for example if whp also had a kw conversion, you need to use [P205:whp] or [P205:kw] depending on which one you needed for your torque calculation. but as there is only a single conversion specified at the moment you can omit them and just use the parameter id. hope that's a bit clear..

kascade · **Posted:** Sat Apr 28, 2007 12:02 am

I added the following to my logger.xml. It seems to work but I'm not sure if the conversions are correct. Could someone check them please?

Code:

                <parameter id="P205" name="WHP" desc="Approximate Wheel Horsepower">
                    <depends>
                        <ref parameter="P12"/> <!-- MAF-->
                    </depends>
                    <conversions>
                        <conversion units="kW" expr="P12*0.793" format="0.00"/>
                        <conversion units="hp" expr="P12*1.064" format="0.00"/>
                        <conversion units="ps" expr="P12*1.079" format="0.00"/>
                    </conversions>
                </parameter>

                <parameter id="P206" name="Torque" desc="Approximate Wheel Torque">
                    <depends>
                        <ref parameter="P8"/> <!-- Engine Speed -->
                        <ref parameter="P205"/> <!-- WHP-->
                    </depends>
                    <conversions>
                        <conversion units="Nm" expr="([P205:kW]*46326.77)/P8" format="0.00"/>
                        <conversion units="lb-ft" expr="([P205:hp]*5252)/P8" format="0.00"/>
                    </conversions>
                </parameter>

ev8siv3 · **Joined:** Fri Mar 24, 2006 7:14 pm **Posts:** 768

Thanks. The WHP calc is dyno based off of the following information and can be modified to suit your dyno's.

http://socob.bb/forum/viewtopic.php?t=284

Jon [in CT] · **Posted:** Sat Apr 28, 2007 12:58 am

ev8siv3 wrote:

Thanks. The WHP calc is dyno based off of the following information and can be modified to suit your dyno's.

http://socob.bb/forum/viewtopic.php?t=284

Can't see anything there without registering, and I'm not interested in registering at yet another podunk Subaru website.

Extrapolating power from just MAF presumes that neither AFR nor spark advance has any affect on power.

Good luck with that.

ev8siv3 · **Joined:** Fri Mar 24, 2006 7:14 pm **Posts:** 768

Jon [in CT] wrote:

ev8siv3 wrote:

Thanks. The WHP calc is dyno based off of the following information and can be modified to suit your dyno's.

http://socob.bb/forum/viewtopic.php?t=284

Can't see anything there without registering, and I'm not interested in registering at yet another podunk Subaru website.

Extrapolating power from just MAF presumes that neither AFR nor spark advance has any affect on power.

Good luck with that.

It's not meant to be an accurate measure of power, it's meant to be a tuning tool for comparison between runs.

Jon [in CT] · **Posted:** Sat Apr 28, 2007 1:24 am

ev8siv3 wrote:

It's not meant to be an accurate measure of power, it's meant to be a tuning tool for comparison between runs.

It's worthless for comparison between runs when AFR or spark advance or AVCS advance, etc. has changed. Now, if you keep all of those parameters constant between runs, then you've got something - mostly higher boost.

west_minist · **Posted:** Sat Apr 28, 2007 2:35 am

Jon [in CT] wrote:

Can't see anything there without registering, and I'm not interested in registering at yet another podunk Subaru website.

Thanks. It always a pleasure.

west_minist · **Posted:** Sat Apr 28, 2007 2:38 am

This is what I have notice on all the cars I have tuned.

I ran through all the ECUTek Dyno's on STI, WRX and othe models and notice that equation. It is not the best 100% perfect, but it would mean that ECUTek isn not 100% perfect.

When we ran Gtech Pro, the results are very similar.

So regardless of AVCS, Spark or fuel, the results is trust worthy enough for a tuning tool.

Freon · **Posted:** Sat Apr 28, 2007 5:18 am

But... if it's only airflow why display it as whp.

If you tune for that, you're just tuning for best airflow, not power. It cannot be used between two runs as a comparison if you changed AFR or timing. Only boost or possibly AVCS.

Why misname it. Why misrepresent what it is. There's nothing wrong with tuning for max airflow, to an extent. It's a valid metric, you should definitely pay attention to it. But it isn't power.

I mean, last time I ordered a pepperoni pizza they didn't give me ham and say its close enough.

Who cares if Ecutek uses it... Let's surpass them.

And it's stupid easy to manipulate. Jack the top of your MAF table, then run your open loop fuel way lean, it will still come out at the right AFR but your airflow numbers will be massive.

BoxerFan · **Posted:** Sat Apr 28, 2007 6:58 am

Jon [in CT] wrote:

Extrapolating power from just MAF presumes that neither AFR nor spark advance has any affect on power.

MAF has almost a direct correlation with power, thus it is a good approximation. AFR & timing would have an impact, however, believe that it's within the small margin of error.

nsfw · **Joined:** Thu Nov 23, 2006 2:23 am **Posts:** 2565

My intuition (which is admittedly not well versed in these matters) suggests the following:
* AFR and timing affect torque pretty substantially
* their impact on torque could be approximated mathematically
* the details of that approximation will be a very contentious topic
* it might be easier to approximate with a table than with equations
* if RomRaider logs that approximation, someone will blow up their engine while attempting to tune for max power, not understanding that those factors also affect detonation
* but you can't (shouldn't try to) protect people from themselves by hiding interesting information

Actually, that approximation (Power = some_functionof(air, AFR, timing)) is something that I've been keeping a close eye out for in the books I bought. Haven't seen it yet, but I'm hoping to find enough information to at least have a mental picture of what the relationships look like. See it in Excel would be even more interesting.

mrf582 · **Posted:** Sat Apr 28, 2007 8:42 am

Converting airflow to 'horsepower' is a stupid f*** idea. If you're simply using it as a tuning tool then just compare airflow values for before/after runs. Don't misrepresent horsepower by including only one of several variables that determines it.

west_minist · **Posted:** Sat Apr 28, 2007 12:42 pm

Freon wrote:

But... if it's only airflow why display it as whp.

If you tune for that, you're just tuning for best airflow, not power. It cannot be used between two runs as a comparison if you changed AFR or timing. Only boost or possibly AVCS.

Why misname it. Why misrepresent what it is. There's nothing wrong with tuning for max airflow, to an extent. It's a valid metric, you should definitely pay attention to it. But it isn't power.

I mean, last time I ordered a pepperoni pizza they didn't give me ham and say its close enough.

Who cares if Ecutek uses it... Let's surpass them.

And it's stupid easy to manipulate. Jack the top of your MAF table, then run your open loop fuel way lean, it will still come out at the right AFR but your airflow numbers will be massive.

I agree with you. I do not know exactly what there uses, since cars that do not produce MAF still creates dyno results.

If there is a better way that RomRaider logger can extrapolate, sure. But there is none right now and values produce are well with Gtech Pro Dyno runs and Ecutek runs. Hence why it is used.

On an actual dyno, that values are evenn very well with spec.

We all know many factors can affect it, as s stated before, his is what we have and compare to other tools used, well with a very % of error.

RomRaider

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Logger Help: WHP and Torque

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