Saturday, September 23, 2006

How Speed Density works

This is the most important work I've ever done, or at least it feels like it. It takes you from sensor data through calculating pulse widths, and all the forms of VE and their particular meaning.

I feel particularly proud, because it all makes sense so far with everything else we've been discovering how these cars run, how the PCM operates and explains a lot of peculiarities of the model GM decided to employ.

The understanding of concepts helped me tremendously. Some things you take for granted, others you just kinda understand, but this puts it all in black and white, solid, precise numbers that show you what and how you wanna run in your car.

I tried to make it as universal as possible, but because of the GM-particular VE form (that I refer to as GMVE) a lot of the paper deals with that. However, the rest is just about universal. Some of the language like ECT (coolant temp) or IAT (aircharge temp) might not be universal, but I tried to explain what they all mean at least at one point, so you can change IAT to AIT if that's what you're used to.

The cool part is that I have gotten some data that confirms the formulas. I've logged all the sensor data necessary, and tried to calculate data normally we'd obtain through PIDs. Cylinder Airmass seems to be very close, with less than 2% error through the whole range of values. Other values dont seem to be that far off either. Considering how many filters there are on anything airflow related, I consider this to be a very good result completely backing up my work.

Due to the fact I needed a lot of math formulas displayed nicely, I had to put it in a Word document, and not a webpage. If you know a way to easily convert it over to a webpage, please let me know, until then, it's just a paper.

I also include a spreadsheet with stock 2004 Z06 values, and convert them to other forms using my math, side by side with the originals.

I hope you guys like it, cause this was a shitload of work.


At 2:04 PM, September 24, 2006, Blogger ClubsportR8 said...

Nice insights mate.

At 4:14 PM, October 23, 2006, Blogger joecar said...

Good piece of work, brings it together nicely.

At 3:17 PM, December 07, 2007, Anonymous Karl Wiener said...

Although I knew the basics behind Volumetric Efficiency prior to reading your paper, it was still quite enlightening to see it as applied with HP Tuners and GM's VCM. Good work, and thanks for sharing!


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