[Yozh]

Guys, I need someone or as many of you, to log your AFR data during a normal drive and during a full fuelling run. Anyone with a tune/downpipe and just stock, would be great. I'm seeing a 13.8 during normal drive and 12.8 low during full fuelling. This may be normal under some circumstances, but I would like to compare please.

Here is an AFR vs Boost for normal drive to a store.

[TDIwyse]

Originally Posted by Yozh

Guys, I need someone or as many of you, to log your AFR data during a normal drive and during a full fuelling run. Anyone with a tune/downpipe and just stock, would be great. I'm seeing a 13.8 during normal drive and 12.8 low during full fuelling. This may be normal under some circumstances, but I would like to compare please.

Here is an AFR vs Boost for normal drive to a store.

Attachment 1080600

I'm looking some really old log files ... found a couple of them that recorded AFR from Feb 2012 time frame. Unfortunately they're coarse time steps (~1 second intervals) and just for light cruising conditions. Ambient air temps are cold and fuel would be a ~30/70 ULSD1/ULSD2 ratio due to extreme winter temps.

Interestingly the AFR was dipping down to ~14.6 at points under light boost conditions. ULSD1 is similar to kerosene type of carbon chains and has a stoich of ~15.6:1. So a 30/70 blend would be ~ 14.9:1. This means the stock setup is showing sub stoich conditions even under light fueling at times...

I'd love to see someone with a stock car and AFR recording capability show what happens during full fueling runs.

I'll keep digging through old logs, but after seeing no issues with the low AFR's and EGT's after first logging data in the early 2012 time frame I stopped recording AFR's ... up until recently with the higher power mods...

[TDIwyse]

Found another one. This one is similar Feb time frame and you can see the air temps are below freezing. This still isn't a full fueling situation by any means, and the coarse time steps of 1 sec may have missed an even lower AFR number, but we can see that stock setup goes below stoich at 14.39:1.
And this is with really cold air temps ... I'd imagine hot summer temps could make that even lower.

[iaknown]

Not sure if it helps because I didn't log/graph but at cruising I am at 29+ AFR and when I'm on it, full boost, it settles around 16.5

[Yozh]

Yeah at cruising we are at 29. One would need to log the data to see the dips. Like TDI, I would be interested to see stock AFRs at full fuelling.

Thank you TDI for posting that data. It is interesting that you had seen 14.3. In my and probably everyone's case I bet it is a combination of lazy tranny, turbo spool/boost and fuel/temperatures. I was turning a corner today, probably was in 3rd gear, low rpms, virtually no boost, pressed the pedal a bit hard and here we go, a sizeable smoke cloud.

[Mik325tds]

Here's a log with normal city driving. Lowest value was 15.45% at superlight acceleration. Surprisingly close to stochiometric...
Mine is stock except for the EGR plates.
I'm going to try to get a full fueling log soon. What else is worthwhile logging to get an overall engine condition overview? EGT, torque, ....?

[Yozh]

AFR vs. Boost vs. Engine Torque would be awesome.

[TDIwyse]

Originally Posted by Mik325tds

What else is worthwhile logging to get an overall engine condition overview? EGT, torque, ....?

I've found grabbing the RPM data is useful. This can be helpful when plotting the data for a full fueling/dyno type run. You can use the RPM as the X-axis in a scatter plot and then see what AFR/EGT's/Boost/etc. are doing as a function of your rpm ramp.

[Mik325tds]

Good idea. And then I assume it would be good to get up to maybe 20mph, get it into 3rd and then full fuelling up to revlimit/next gear switch (or police siren...) as opposed to doing a 0-70 pull, right?

[Mik325tds]

Man, this car is fun! I still have a puls of 140
Less fun is the new Excel - can't figure out how to assign data to the axis. Here's the data for now. These were three pulls as you can see from the RPM screenshot.
AFR seems to be good. Gotta go now. More tomorrow.

[Yozh]

Thanks Mik, can you post what is the lowest AFR you are seeing. Not clear from graphs.

[TDIwyse]

Thanks for posting data.

There's a point on your plot that looks like the AFR is well below 10:1. That's interesting. How many samples/sec is this data?

[Mik325tds]

At sample point 805 somehow torque inserted another header line into the log data, which was interpreted as 0 for the graphs. You'll notice that the RPM went down to 0 there, too.
The lowest actual reading of AFR were two samples of 14.48 just before the engine reached idle. Makes sense, since there probably isn't a lot of air-flow and the DDE is injecting fuel in order to catch the engine from stalling.
I'll look through my other logs and see if I can find more low AFRs.

[TDIwyse]

Originally Posted by Mik325tds

At sample point 805 somehow torque inserted another header line into the log data, which was interpreted as 0 for the graphs. You'll notice that the RPM went down to 0 there, too.

Ah. Did you "stop recording" and some point and then "start recording" again? I think it inserts a new header line when that happens.

[Mik325tds]

Yes. I set it to start logging when App starts and then opened and closed torque so I did get several files. I think this is just torque hicking up.
Anyway I'm getting the hang of the new Excel and here are a couple more prints of a 0-80 pull and then some hard accelerations. Lowest AFR were 15.41%, 15.6%, 15.8% in these pulls. So, well behaving for full fuelling.

[Mik325tds]

TDI, by the way, congrats to your 1000st post! What are you doing in your spare time?

[TDIwyse]

Originally Posted by Mik325tds

TDI, by the way, congrats to your 1000st post! What are you doing in your spare time?

Ha! Ugh, I must spend too much time on here...

Thanks for posting data.

Right now I have no spare time. Remodeling a bathroom and a big deadline at work next month are keeping me too busy...

[Mik325tds]

Originally Posted by TDIwyse

Ha! Ugh, I must spend too much time on here...

Sir, Major, sir, you're still under 0.06 posts/hour. Doesn't sound unhealthy, yet.

[DWR]

Not trying to revive this thread, just thought I would add some data to the forum library. Looking at some old logs, in stock configuration, at full load, upper rpm ranges, AFR averaged @ 19. But, the readings are ragged. Quite a bit of variation from sample point to sample point, using Torque App.