Just double checked, you've got it. I appreciate it!

 

Bored at work so here you go. I still don't know how accurate these graphs are, but when I did mine a couple weeks ago whp and airflow in lb/min seemed to be in rough agreement (typically lb/min x 10 = whp). I guessed at vehicle/driver weights and tire size.

Fireindc's 3rd gear pull.

 

Thanks much! What exactly did you edit? I've downloaded open office calc and I'm playing with this now.

Looks like a good base to start from, apparently do need some more tuning. Have yet to play with the timing map I'm using at all, boost peaks at 160kpa and trails off to 149 kpa at redline, so not quite 10# per psi at all

 

I trimmed out all the data that was not tps, time, and rpm. Then I clipped the remaining bits down to just the pull. Then I changed the tps column to read 100 as the value in each cell. I also renamed the respective columns "Time (s)" and "TPS (%)"...RPM is fine (I deleted the column that shows RPM/100 and kept the one that reads the full value). When that was all done, I saved as a .csv.

And 10# per psi...not the value for that comparison. Airflow in pounds per minute, not a measure of pressure but mass flow. The generally accepted rule of thumb is that for every lb/min of airflow you can estimate 10whp.

 

Thanks for the details, I have something to play with now. Still needz moar power, and this wastegate wont let me hold anything past 10psi to redline, even with a helper spring. Looking into buying a 10psi wastegate and fabbing up a bracket for it.

How does one go about calculating this?

 

You know this is all unnecessary right? VD will clip the run to the WOT sections of the log. It knows that if 87 is the max that TPS gets to that its the WOT value. It is pretty smart when it comes to trimming. Also other columns you can leave in there as you can graph them too. Im just trying to save you a lot of work.

 

Thanks Brad! Given my multiple failed attempts to graph my own datalogs I wanted to be as specific as possible this time. And his TPS reads only 48 and 49 since it's not variable...didn't know if that would translate well.

Does the MS logger capture mass airflow in any form, or can you ask it to display that info? If yes, and it's gm/rev, here's a formula to convert to lb/min:

lb/min = g/rev * rpm * 0.002204623

 

I think 1.1.8 has a TPS floor so it does consider anything less than 50 to be less than WOT so that may not work. I think Ive removed that in the upcoming 1.1.9

 

1.1.9?

Text output?

 

Not as far as I know, it's MAP based. Either way I know with my turbo setup at 10psi I should be around 200whp, then to calculate for altitude(7k+ ft, barometric pressure is 80 here, vs 100 for sea level) you take off about 20%, so 180whp. That said, I'm still 20whp off. I need some people to look at my timing map, though this probably isn't the thread to do so in - so I'll open a new one sometime here.

 

Only if you have a maf sensor connected and setup properly in megasquirt
And even then you won't know if its correct unless you are actually running with maf based fueling as well.
It has two outputs MAF and CalcLoad ( MAFMAP actually but it has no relevance to MAP )
MAF is in grams a second and calcload is just a load # based on displacement of the engine, etc of the maf formula.

Since its a grams a second its even easier to convert it over to lb/min

 

Ahh ok. I'm in MAP-based speed density too, but ECMLink allows users to set up the VE table with a native MAF sensor, and there's a built in tool for refining it further based on fuel trims.

That's basically how ECMLink calculates airflow after the speed density VE table is originally established with a MAF sensor.

 

I don't know how I missed this thread for months... I will have to try this out. Has anybody compared this to a real dyno? How close is it?

 

And if you dont have a maf you can use the same math the VE table uses to get calculated air flow based on MAP, IAT, and RPM.

Here's a nice write up with more info than you could ever want. https://dl.dropbox.com/u/18163809/Ho...ityWorks16.doc

 

1.1.9 is the version that is about to get released. Im very close to releasing the next version

Text output is on the priority list but its falling next to saving custom cars. They both need done ... but work is working me 60 hrs a week so Im doing all I can along with trying to get my ex wife out of my house thats 9 hours away. Dang complications. If someone would get her out I would be able to get more done on VD. Any takers?

 

Pretty darn. There are fudge factors if you're after a perfect match. BUT, physics (VD and 1/4 mile runs) is actually a more accurate measure than a dyno anyway, as long as you pay attention to things like temperature, wind and slope.

VD is repeatable. Therefore, you can use it to tune.

 

Took the words straight from my finger tips ...

 

Make sure it's not windy out.

 

1.1.9 has been released ... Enjoy!!!

 

ECMLink support!!

Donation to be made shortly...thanks!