Sick car. Why is it that whenever I see a video of a modified diesel, it's spewing thick black smoke everywhere? Isnt that poor tuning? Dosent that cause very high EGT's?
Brief puffs of black smoke (as seen in that video) doesn't always indicate high EGT. It's sustained high loads where you should avoid heavy smoking without an EGT gauge. If someone has a EGT gauge and smokes a ton, then so be it. Diesel power is primarily based on fuel, so more fuel means potentially more smoke.
Some people want to squeeze out the last few HP by overfueling and some others prefer good power while appearing clean (smoke-free).
It should be made clear that it is STILL possible to exceed safe EGT limit without producing any smoke. So if you're doing more than moderate power enhancements, an EGT gauge is always a good idea.
In this video there are too many unknown variables to determine whether it's good or poor tuning. I.e. Is his turbo so large that he wants to pump a lot of fuel (i.e. smoke) at low RPM in order to get the turbo to spool up a little quicker? This would make sense on a tight autocross course. Should he have ported his head to improve low-RPM airflow to reduce the smoke?
It is possible to tune the chip to reduce off-boost smoke. We can't really judge his tuning based on this video only.. we need more information; a full mod list, take logs, analyze his chip, type of fuel he's using, etc.
For what it's worth; in most cases the excess low-RPM smoke is indeed a result of poor chip tuning. I see many VNT-15(stock) and VNT-17, VNT-20 equipped TDIs smoking a ton at low RPM (or in the entire RPM band) when they could have smoked a lot less without losing much power (if at all) after a proper chip remap.