Oh, and a big thanks to you. I probably should have given you some credit in the thread since I basically ripped most this stuff off from you, and then just dumbed it down for general consumption.
Great write up Jran. I did a thread years ago on AZ, not sure how outdated it is now. This was at a time the 3 tuners didn’t like their logs posted, thus I added “don’t be a pussy” lol.
http://www.audizine.com/forum/showthread.php/474796-B8-S4-log-thread-Post-your-VCDS-logs-here
Good stuff reminding to get the ambient pressure and temperature such that boost can be calculated (if they desire) and more importantly, log comparisons can be understood.
Side note - I think that calibrators mostly care about the absolute air charge in hPa - not “boost”. Absolute pressure and temperature define what the cylinder will see in terms of intake charge ultimate temp and pressure, and ultimately the limits of the motor. Which is why you don’t see a “boost” or gauge pressure reference in the parameters anywhere in any Audi.
Thanks for posting a link to that. I’ll probably add it to my thread just as another good source of similar information.
On the other site, I added a link to your thread, and several others that were either useful in terms of logging or had good examples of logs from various tunes.
Updated with fields for fuel pressure, trims/adaptations, and injector duty cycles.
Edit: It wouldn’t let me edit the OP, so I added the changes below…
Additions:
[B]020- Exhaust temperature 1 bank 1 460.0 ∞C
021- Exhaust temperature 1 bank 2 459.5 ∞C
238- Lambda probes actual; bank1 0.9971
13- same?
239- Lambda probes actual; bank2 1.0049
14- same?
244- Lambda probes specification; bank 1 0.9971
245- Lambda probes specification; bank 2 0.9971
246- Lambda probes specified; bank1 0.9971
247- Lambda probes specified; bank2 0.9971
(note that 244-247 seem to be the same thing, the specified Lambda value, so logging one is likely sufficient).
194-199: Knock sensor voltage[/B]
Table to convert Lambda to Air:Fuel ratios:
http://i570.photobucket.com/albums/ss146/jran76/LamdaVsAFR_zpsj6s7ctd1.jpg
Fuel Pressures, Trims, and Injectors
[B]87- Rail pressure actual
170- Rail pressure specified
22- Fuel pressure
187- Fuel pump, actual fuel pressure
Fuel Trims/Adaptations (%)
47- Long-term adaptation; bank 1
48- Long-term adaptation; bank 2
63- Short-term adaptation; bank 1
64- Short-term adaptation; bank 2
Injector Pulse Width (IPW in ms):
609- TI_1_HOM[0]
610- TI_1_HOM[1]
611- TI_1_HOM[2]
612- TI_1_HOM[3]
613- TI_1_HOM[4]
614- TI_1_HOM[5]
To calculate the injector duty cycle, it is something like: (RPM x IPW)/300=IDC
[/B]
Good stuff Josh! I started to log a few of these with the e85… Appreciate you sharing!
No problem. I’m going to go back and add some additional information about the new ones I added when I get a chance. I got most of these from talking with you and andthen about the E85 stuff, and just wanted to put them somewhere before I lost them.
One thing I’m still trying to figure out is the injector duty cycle, and I’d love to hear what you guys think about this. I’ve read so many conflicting things about how to calculate it on a DI motor, all the way to saying it’s not really possible to accurately calculate at all. If anyone has any ideas, I’d like to hear them. Here’s where I’m at (just thinking out loud):
On a port injected (PI) motor, you can take the injector pulse width (IPW), and calculate out the injector duty cycle (IDC). The normal formula is IDC=(IPW x RPM)/1200
In theory, the injectors have to spray much faster on a DI motor (4x in theory according to bhvrdr). So, you would divide by 300 instead of 1200. With that said, it doesn’t calculate out right as you end up way over 100% in most cases.
**A typical PI motor has an IPW around 2.5 to 4ms at idle, and may max out in the 15 to 18ms range in most cases.
**The 3.0 TFSI (DI) motor has an IPW around 0.6 to 0.7ms at idle, and seems to max out in the 7 to 8ms range. The logs I’ve seen so far show it maxing at around 8ms at 5200 RPM, and then declining to around 7ms at redline.
I bring up that last point because a lot of what I read said it doesn’t really matter on a DI motor. That it’s actually better to run the injectors near their maximum duty cycle, and in a lot of cases the need for more fuel is made up for by additional pressure.
Thoughts?
Just to add another data point to the injector pulse width/duty cycle conversation (that I’m having with myself):
My APR 93 stage 2 tune hit around 6.4ms at 5200rpm, and it tapered down to 5.4ms at 7200rpm in 2nd and 3rd gear.
The EPL full E85 stage 2 tune with the dual pulleys hit around 8ms at 5000rpm, and it tapered down to 6.2ms at 7200rpm (not sure on the gear, but I think 3rd).
I’m reading this with interest - don’t think I can add knowledge, but I have a few questions if you will indulge me…
A quick glance at APR’s torque curve shows torque at redline a bit over 20% below the peak near 5000 - that seems to roughly correlate to the 6.2ms vs 8ms width times you quote. And (extreme simplification I know) air available is proportional to torque…
It’s been too long since I’ve looked at logs - is absolute manifold pressure also down 20+ % as well to match the injector width time reduction, or is the MAP stay higher but the resulting internal restrictions in the intake system at higher flow (revs) result in less air and a need for less fuel? Is AFR constant from 5-7200?
Good points to consider. I had to go take a look.
Absolute pressure does continue to rise linearly all the way to redline for the most part. On my most recent logs from 5000-7200 RPM’s it goes from 1900hPa to 2100hPa in a pretty linear manner. The recent dual pulley logs I have go from 2100hPa to 2250hPa.
Looking at a recent set of logs from an APR stage 2 tune, lambda stays pretty steady as RPM’s climb. In 1st-3rd gears, it’s right around 0.84-0.85 (12.5:1) the entire time. In 4th and 5th gears it richens up just a tad to 0.80-0.81 (12:1). It may jump around a little, but it’s right at those numbers most of the time.
The 3rd gear dynos I have show the AFR (measured at the tailpipe) for:
-Revo stage 2 steady at 11.5:1
-APR stage 2 steady at 11.2:1 (older V2 tune)
-GIAC stage 2 steady at 11:1 on their older tune
-GIAC dropping from 12.5:1 to 11 from 3000-7000 RPM on their newer tune (not sure what was up with this one as it looked vastly different than the rest)
I should be hitting the same dyno again this week with my APR stage 2 car, and an EPL dual pulley/E85 car. Hopefully we’ll hit the strip together shortly after…
So : lambda remaining fairly steady, and decreasing injector pulse widths - would indicate less air present as the revs rise? (same amount of air + less fuel would lead to higher lambda readings?).
Could one use AFR, injector widths, and MAP to roughly calculate volumetric efficiency vs. RPM?
Air mass and pressure both increase, but so does fuel pressure for the most part. I think that is at least making up some of the difference. It does from under 1900psi to over 2000psi in the same span.
I found out today that the B8.5 (at least the 2015 I logged) has very different field names and ID#'s. I tried to use my normal parameter file, and it was completely jacked up. I’ll do some logging on the car again next week, and update this thread with the new ID’s.
So, just a heads up for now that if you have a newer car, some of the fields may be different both in name and ID#.
I think primetime told us about that a few years back. This may even have happened within the prefacelift years
Yeah, it seems like it may just be the later 2014-2016 models. The fact the regular existing tunes bombed on those models without some changes is a pretty good sign something with the ECU changed. I have a 2013 and 2015 I’m going to try and log in the next few weeks, so I’ll sort it out and update this.
ftfy
For my car the name/ID’s changed with some releases of VCDS… They seem to get more complete with newer releases, but he ID#'s can shift around… Can be frustrating to re-find everything if you have saved parameter files.
Good point. There is a new release from the last few weeks. My plan is to update to the newer version, and then figure it out for both ECU’s.
In this case, I literally unplugged from my 2012, plugged it into the 2015, selected the same parameter file, and a bunch of weird stuff was checked that I’d never heard of. When I went looking for the fields I normally log, half of them had slightly different names.
Wrong thread! lol