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:



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

Best!

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

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

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.

disable armd in the tune

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.

It helps, thank you!

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