No, req is req after losses (at the throttle body inlet, or, if we weren't using the misnomer "MAP", the actual MAP, which is in the intake manifold, downstream of the throttle body). That is because the PID works on the difference between req and actual (measured at the tb inlet).
P/R supported by the turbo is before losses (at the turbo compressor outlet), which is nowhere near the pressure sensor.
Even worse, you're also neglecting intake losses from ambient to the turbo compressor inlet, which makes the P/R you're basing your req boost even further off.
http://s4wiki.com/wiki/Compressor_mapNo. You don't need an upgraded MAP because the turbo will never get that high. And if you did, you'll hit the hardcoded (in the ECU) MAP limit, which requires the ASM 5120 hack, which is definitely beyond your ability right now
NoNo. Actual boost should not deviate from request, except during spool.
You completely misunderstood how the boost PID works, what P/R is, etc.
Alright guys ive got another run at this, probably get a few more
Nos but that’s alright. So Ive looked at this website:
http://www.vaglinks.com/Docs/Audi/B5/S4/AweTuning_2.7T_Intercooler_Everything.pdfIts super cool, shows the difference between RSW, AWE, and Stock Intercoolers. It shows the pressure drops and temperature drops across the rev range.
Ive also looked at this website, as you recommended:
http://s4wiki.com/wiki/Compressor_mapIve used the 1st link to create part of my excel table showing the pressure losses for the stock IC’s.
Ive also looked on line and in my current location Buffalo MN area it is 900 ft above sea so the pressure is 14.18 calculated on a 65-degree day.
I then calculated my boost from my pressure ratio, that I had collected from my compressor map(90% of the surge limit to 90% of the choke limit). This percentage can be increased but only experience can tell how close to get to the surge/choke limits. I used the calculation on the s4 wiki page for this btw with Pboost = PR(Pambient-PICdrop)-Pambient-Pinlet(used 1 for this).
My only question with this is that my requested boost line without losses drops down to just over 10 psi at redline, and my requested boost after losses line drops down to 6 psi. From what I have read on the forums, people can hold anywhere up to 16 at redline??? I have not verified this information from a viable source.. This might be possible if I ran the requested boost closer to the Choke limit of the 03?
I’ve also researched that our MAP limit is at 22.5 PSI. Some Say 22 PSI. This Boost curve maxes out at just over 22 psi so itd have to be dialed back just a bit.
I also think I have a fair understanding of PID. I have read about it on the web and wiki, even before I got chewed out by nyet. The best way to explain the PID is to point to a graph that is ever increasing and decreasing. Now imagine a second graph that is a chasing it just like that 2-D helicopter game we used to play as kids. PID controls the second graph(actual boost) to increase a lot, or a little based on what direction the front graph is going(requested boost).
What ive also learned from this is that our stock intercoolers are very restrictive. And cant flow near as much air as we would all like(infinite )
Also lastly a note for nyet, I do greatly appreciate your input, and want to hear it! However just as an FYI, I am a mechanical engineer that has worked in testing and calibration and now I’m onto engine design(My heart still is in calibration and testing but this is where the world led me). Anyways please do not be so quick to judge as I do have a relative idea of what is going on, just missing a few pieces. Thanks!
