Advancing injection timing?

[gsxr]

Car: 1987 300D, 124.133
Engine: OM603.960, 3.0L, 6-cylinder with aluminum head


I just advanced the injection timing from the factory spec of 15 degrees ATDC to about 13 ATDC. Perhaps it's the placebo effect, but it *seems* to be a hair more responsive off idle and at lower RPM. The top end seems just as good if not a hair better (hard to tell). However, I'm getting a decent amount of smoke at full throttle runs to redline above about 3500-4000rpm. Not a huge cloud but enough to easily see in daylight. The smoke does not appear at lower RPM's. Has anyone else experimented with this? Should I expect a drop in fuel economy? Or am I the guinea pig?

Note: The head was recently replaced and I used a dial gauge to set the TDC indicator, so yes it is accurate. And I have the static RIV timing tool to set the pump exactly at 13 ATDC, it's not a guesstimate setting.


Best regards,