NefMoto

Hello,

It was time to do a little revision to my 1.8T S3 engine due to ~120 000km and 6 years of everyday driving on it after my last rebuild, since there was some wear in the pistons and rings, respectively increased oil consumption and the whole story...

I used the opportunity to swap the head with a big port one, did some work on the intake manifold to match the port size and the car runs great now, at least to a point.

I have a GT2871R @ 1.9bar and 630cc injectors, forged rods, enough fuel and cool air, everything else is stock. I was putting down about 270kw at the wheels and I was noticing about 4.5-6 degrees correction in timing during WOT on the highway (less on the dyno) with the small port head.

Unfortunately my tuner is no longer around to handle this, so I've recently started to dig in the maps myself, adjusting cold starts, idle and other non-power-related maps. Now I am little confused about something and little scared to touch where I know a really good tuner has done the mapping before me, but I feel the big port requires some adjusting.

Now, with no maps changed, I see absolutely no CF, 0! The car feels really good, much better than before, but towards the end of a 4th gear pull and especially on 5th I notice an increase in EGT (about 980C on 4th and over 1000C on 5th and increasing, after which I let go the throttle), I also get misfires, but still no CF! On a colder night I would not get the misfires, but still a pretty high EGT. I tried running richer via LAMFA, went all the way up to 11:1 just to see what happens, but that did not solve anything, it made it worse of course, so I went back to about 11.7 where 'kelesha' (the pro tuner) had left it. I've been reading that increased timing might reduce EGT, which also makes sense given that my CF is 0, which begs for some more timing until I see about 1-2 CF, but in the same time the big port with more airflow and cylinder pressure suggests that I reduce timing, no?

So my question is kinda obvious, should I try to increase or decrease timing, or should I leave it alone and look elsewhere? Here's my current timing map:

(http://www.nireti.com/audi/kfzw.jpg)

Any suggestions are welcome and appreciated! I can do some logging if somebody finds this interesting and wants to play along :)

Best!

Pointless to comment without logs.

Makes sense, what's best to log in that case? rpm, load, boost, actual timing, cf, what else?

Somebody should put an answer to that question somewhere. I mean, it is so rarely asked

Oh. Wait.
https://s4wiki.com/wiki/Tuning#Logging_utilities

Thought it would be more helpful to narrow down the list to be on point. Nevertheless, will log with all these. Thanks!

More data always makes analysing, and diagnosing easier :)
If I could log all 700 and something variables everytime,
i would do it. I love all the data, gives me an exact picture of what's going on :P

Adding fuel can not make EGT on an OTTO engine worse. In fact it lowers EGT (provided you were running richer than lambda 1).
I think you need to read a book about ICE-s before attempting to tune anything, as you do not seem to have the basics down.

When I say it got worse I did not mean EGT, EGT actually was little better, but still getting over 1000C even on 4th, so I did not solve the main issue. What I meant by 'it got worse' is that the car did not feel right and also I had so many fuel spots on the trunk door, it was ridiculous.

Why would I increase fuel trying to solve an EGT problem if I don't know what this is and what it does?

Also I am not trying to tune anything, the car is pretty well tuned, I am just trying to solve what I consider is an issue that happened after a hardware change, big port head install to be precise.

Anyway,  I've attached 4 logs. Log 1 is running the angles from the picture in the first post and I have cam overlap all the way to 5000rpm.

The other 3 logs are with cam overlap down to 4500 (500 more than stock), as well as + 3 degree marked in the red in the following picture:

(http://www.nireti.com/audi/kfzw_plus3.jpg)

All this actually helped in my opinion, I did not notice more than 970C on 4th and I was only getting about 1000C towards the end of 5th, my absolute max was 1020C for a bit right before limiter on 5th.

Also it's worth mentioning that it's quite hot, over 30C ambient, as well the coolant was getting well over 100C. I had random misfires, but no major CF, only 1.5 deg on cyl. 3.

Any feedback if these logs are ok and if my new timing on the marked region is ok would  be much appreciated.

Thanks!

P.S Also I had to switch on logging prior to starting the engine, since there seems to be some weird issue with connection, so first rows are pretty useless until I get up to 4th. Also that was on the highway, so occasionally I had to let go the throttle because of traffic, all that is visible on the logs...

disable armd in the tune

Because of timing oscillations?

Alright, let me ask this - is it a right strategy to increase timing until a noticeable CF, let's say 4-5-6 degrees is reached and then pull back to about 1-2 degrees? Would this give me the optimal timing the car can handle or should we always aim for 0 CF? Is there a number that we should aim for that in your opinion is best for a heavy boost 1.8T? From what I read 10-15 degrees timing is good, but does this mean it is bad if the car is able to make 20 without knock and no CF?

Obviously that is best seen on the dyno, but I will have access to one little down the road.

As a whole, aim for 0 CF

If you think you will be running different kinds of gas, aim for 0 on the best gas you are going to run, but never more than single digits on the worst gas and/or worst conditions (high IAT etc).

Absolute best timing is a poor metric because it can vary wildly depending.

Hope that helps.

It helps, thank you!

Given the increased cylinder pressure that comes with more timing, does anyone have any observations if the stock bolts and head gasket for the 1.8T might not hold? I noticed my timing was set to -1.5 degrees from stock by the tuner initially, do tuners do this for safety in general?

IIRC, stock is around -1.5 in that region.  Compare to ORI.  You'd be surprised at the changes your tuner hasn't made.

Exactly, stock is -1.5 from that region and the tuner had set it to -1.5 from stock (so -3 from the picture), I wonder why that is, safety? Generally it makes sense to increase timing, but I am sure I am missing something. The dyno will show best I guess :)

Finally was able to go to the dyno. Best results were achieved with + 2.25 degrees from stock. I guess big port helps hold slightly earlier ignition with no timing pull.

What about your egts? The engine is bam according to your part number in the logs. Do you still have the oem egt probe and bts activated?

I no longer have that and it is switched off, I have another one that I monitor inside. EGTs get about 940C at WOT on 4th, so that's good. The car runs about 15-20 degrees timing. I will post a graph when I get it from my laptop, which is in the car, but I noticed that I get some jumps of timing across the whole range and about +/- 4 degrees at WOT. Will add a log to illustrate little later, but in general what oscillation is acceptable in your opinion/experience?

Here's a log of 4 runs on the dyno (attached). Is this oscillation normal?

(edit: excel obviously breaks the rules, please read two posts down)

Please do not post excel files.

Post the original csv, as stated over and over and over again just about everywhere :P

I don't know that I can use more red or a larger font

http://nefariousmotorsports.com/forum/index.php?topic=4094.0title=

jzz, there you go, the idea was to make it easier on anyone reading that...

Now that that's out of the way, any useful comment?

Also, I posted another csv with all rows that are not wot removed, is this not ok, I am not sure how strict the 'do not post edited log files' is.

Those have BOTH been edited. Please upload the ORIGINAL csvs, with headers complete, so ECUxPlot can properly detect the logger used to create the cvs.


ECUxPlot handles this for you on unedited files.

I see, the plotter tool needs the headers... ok my bad. How's this one?

edit: they are the same file, not sure how it got uploaded twice...

why is your wg dc locked?

other than that, it looks pretty good.

do you expect it to spool that slow? If so, you will likely eventually see a pos deviation code unless you adjust your boost req accordingly.

The turbo is 2871 with 0.86 a/r, it has never been able to spool quick. As for the dc I guess it is because I run 3bar map and 1.9bar boost, both of which are non standard for this car and that way they simply work, I did not tune these and am not sure.

I was only adjusting timing and fuel and if these jumps are acceptable I am happy, the car feels alright.

Thanks!