Thursday, June 25, 2009

Parametric VE explained



This is an explanation, representation, and pros & cons of the Parametric VE.
I was told to cut it out with the math, so here it is watered down for easy reading. I kept the math simple, I might have mentioned matrix multiplication once, but I think I got away with it.

It's way too involved to be a web page so here's the downloads:

Word2007 version PDF version

enjoy and for the love of Newton, please comment profusely,
Marcin

6 Comments:

At 8:03 AM, June 26, 2009, Anonymous Anonymous said...

what about for those that want to see the matrix algebra ;)

 
At 8:17 AM, June 26, 2009, Blogger Marcin said...

well sunneva... no way to please everybody is there? :)

This paper is a much shorter version of a paper I wrote, that talks about using the Parametric VE to optimize VE and Bias simultaneously. The pic in this post and the one on top of the paper is generated from a real world LS3 with headers/intake that's had it's VE/Bias tuned with my software.

If you want gnarly details quickly though, just hit me up on aim/yahooim.

 
At 11:58 AM, June 26, 2009, Blogger joecar said...

Marcin,
Good explanation... (altho I do miss the math).
Joe

 
At 3:22 AM, June 29, 2009, Anonymous Ian said...

Great paper Marcin, thankyou for going to the effort and sharing!

If that is your LS3 "VE" table(or more correctly the airmass model for the engine?), is it stock?

And if so, what min/max % changes did you see in the surface?

Also are the "walls" on zone changes really as substantial as they look? Do they make much difference to the operation of the engine?

Cheers, Ian

 
At 1:19 PM, June 29, 2009, Blogger Marcin said...

The pic in this post and the one on top of the paper is generated from a real world LS3 with headers/intake that's had it's VE/Bias tuned with my software.

However (and this is a big however), I dont think I had the filter lag algorithm figured out correctly, throwing off TEMP and thus the resulting GMVE. So I wouldn't really look for any numerical clues from that yet. Also notice that I dont have much WOT data, so that range is obviously lacking.

If by 'walls' you mean zone boundaries, then yes, you want them to line up a lot closer. I'd imagine there'd be a major hesitation/jerk the moment you'd cross a boundary on a unaligned edge.

 
At 4:07 AM, July 30, 2009, Anonymous Ian said...

Thanks Marcin! Any ideas on how the "prediction co-efficients" in HPT "dynamic airflow" affect the GM VE? If at all?

Cheers, Ian

 

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