Dyno Maths Library

[FWombat]

Somebody just PMed me a log that I took a look at.  My library wasn't giving good numbers, and it took me a minute to figure out why.  It was because Engine Speed wasn't being logged fast enough!  

You must log Engine Speed at the fastest possible rate!  If you're using the internal logger, make sure sampling is at 250/sec, and Engine Speed is on a fast channel.  If you're manually logging using a parameters window, be sure to right click on Engine Speed, and change the update rate to Fastest

- Brian

[TDtrader]

It's a 6KB file, has a bunch of gibberish when opened in Notepad, and I'm running version 3.06 of AEMLog...

[FWombat]

Hey FWombat.  I have been successful with your dyno library.  It is giving me fairly accurate number compared to previous Dynojet numbers.  I showed this to my dyno guy and he wants to log a run while on the dyno to do a straight up comparison.

Good to hear it's working for you.    I've found the numbers to be pretty accurate on my car as well.

Using it to log a dyno session could be tricky.  In order to calculate power, you need to know the mass being moved.  In my equations, I use the weight of you and your car.  On a dyno, they use the weight/resistance of the rollers.  Make sense?

I'm no dyno expert, but I think some dynos use a constant roller weight as load; in this case, we'd just need to know the effective weight of the rollers.  Other dynos use electric motors to provide variable load.  On a variable load dyno, the load would have to be held constant in order for the library to work, and we'd need to know what that constant weight was.  

- Brian

[Hau]

Ben,

See if this helps:
Save the math file in the math directory of AEMLog
Open AEMlog and under the maths menu click open library.
Once that screen comes up, go in and edit the values for your car (weight, coefficient of drag, tire size....)
Hit save and close the screen.
Notice on the bottom it shows your math library that is active.
Go back to the math menu and click on calculate on open
Now open up a log file.
The screen for calculating maths should pop up.  
Click OK and it should work.

[FWombat]

It's a 6KB file, has a bunch of gibberish when opened in Notepad, and I'm running version 3.06 of AEMLog...

Were you ever able to get this to work?  

- Brian

[TDtrader]

No, no luck.  I tried saving it in different directories, including the Math directory of AEMlog but opening up, it still insists I have no equations created.

FWombat, how do you create a math library?  I don't need the equations per se as I know them already, but when I looked at creating a library I could not figure out how to use data from the AEMlog channels for input into the equation.  If you could tell me that (I did a separate post but no one answered) it would be helpful...

[racerxadam]

I had the same problem getting the "No equations have been created" message when i first tried also. I backed up the stuff i wanted to keep and then uninstalled and reinstalled both aempro and aemlog with the most recent files listed in the download post. Now it opens fine and calculates. Maybe you should try to update to the most recent available download of the software.  

[TDtrader]

I tried that - uninstalling and reinstalling.  No dice.  I found out something funny - I had another post as to how to create a math library because when I tried that I don't get any options for Inputs from the channels I logged and apparently you should (I called AEM EMS tech support for help and apparently my AEMlog is not behaving correctly), so I can't even create equations on my own.  Something is wrong with my installation on 2 PC's which is very frustrating.  It seems like I'm caught out with some kind of bug on AEMLog.

[TDtrader]

Interestingly enough I tried it on a 3rd computer that's running Windows 2000 and it works.  Strange.  However, the dyno #'s I get are strange - I see a peak rwhp of 240 for my single turbo SP63 Mkiv running 20 psi.  I *know* that it's stronger than when it was BPU on stock twins, and it dyno'd at 425 rwhp on pump gas on that setup (394 rwhp at 17 psi as well)...so something with this equation is not working for my car.

[BLKMGK]

Did you modify the variables like gear ratio etc. for the Supra? That will throw it way off if you haven't. You need to remember it will only be accurate in one gear too...

[TDtrader]

Yes it was all modified for the Supra, I calculated frontal area, looked up the Cd from the Supra brochure, etc.  Later when I have time I will look at it again to make sure I didn't mis-type something.

[FWombat]

Make sure you've got all those constants right!  As long as all those numbers at the top are accurate, it should work.  The math is the same for every car.

Also, just in case you missed earlier posts about it, make sure that you're logging Engine Speed at the highest possible rate.  

- Brian

[Mike tsai]

It seems to work fine for me.  Only thing is I get very low hp.  50hp.. hehe
I didn't know my gear ratios.  Does anyone know what gear ratios is correct for a 98 Honda Prelude Type SH?  If so, please post it or pm me.  Thanks.

[GN]

It seems to work fine for me.  Only thing is I get very low hp.  50hp.. hehe
I didn't know my gear ratios.  Does anyone know what gear ratios is correct for a 98 Honda Prelude Type SH?  If so, please post it or pm me.  Thanks.

1st - 3.285
2nd - 1.956
3rd - 1.344
4th - 1.304
5th - 0.812
If you want to do it in reverse - 3.000
Final Drive - 4.266

[Kevin Hoare]

I tried this on some of my runs from the summer, and I'm getting a low HP reading as well. I have a Supra and entered all the appropriate data. My #'s must have been off by at least a factor of 2.

Hmmm, maybe the sample rate was low.