you're assuming every engine is the same.. it's not...
Also you're making very general statements... the more boost you run the more chance of knock, the more fuel you will need to run to cool the charge and keep knock to a minimum... the problem is you get to a point where combustion suffers when going too rich (usually lower then 11.3 or so) and you actually start to misfire from too much fuel.
16.4:1 is too lean IMO... some car might be ok with it.. but generally that is pretty rare, and if they are they're completely stock.
Your assuming that my comments were general statements. They aren't.
Read:
I only use 93
You can go a lil richer. Depends on gas and other factors like IAT, etc.
Edit: 99.9% of all my tuning work revolves around 1.8T.
Take all of my posts with a grain of salt, just like you should with every other statement on an internet forum. The only way to figure out the best AFR for your setup is to do a custom tune. I'm just saying what works for
ME, and I wanted to contribute something to this forum.
In internal combustion engines there is a lot of factors that dictate what AFR you should run. In fact, just engine wear could affect that. Some like to be a little lean, some like to a little rich. The first graph I posted was for NA applications. For turbo applications you obviously want to go a little richer but it still gives you a good starting point.
Also my 12v doesn't seem to mind being lean. I use only 93+ though.
Stratified injection engines are another beast. You can go leaner on a stratified injection engine (TFSI/FSI) than on a 1.8T/2.7T and make good power.
