Diesels are dirty running things , always were. Trouble is in for example France , diesel cars became more common than petrol cars as long ago as the 1980's.
A) Diesel was considerably cheaper than petrol in Europe for many years
B) In all those small cars ( think Peugeot 205's , VW Golf's etc etc) the fuel consumption was WAY better than the equivalent petrol so the cars cost more to buy new but MUCH MUCH less to run.
Into the more modern "enlightened" times and the Euro fuggers decide Diesel is a dirty word ( no pun intended !) , with particularly nasty exhaust particulates. To the extent that diesel vehicles are now banned in the inner Paris metro area.
In comes the DPF to catch all them fugging wee particulates as demanded by various Euro authorities. We get them in many Australian market cars "because"..
I have a 2012 Nissan Navara D22 ( or my missus does actually ) , one of the last non-DPF equipped diesels sold. I wanted it that way as I knew from UK contacts that they ( DPF's) were trouble waiting to happen.
Now even on that D22 , after a while between tankfills , if you have been cruising at a steady speed and then floor/accelerate swiftly , it chucks out big black clouds from the exhaust, almost embarrassing, that's on an 88,000 K's vehicle with the engine oil changed every 5,000 !
Down to Supercheap and in with the Diesel injector cleaner ( does not matter which brand , just the cheapest/best bulk deal on the day ).
That lasts for a wee while , sometimes 6 to 8 weeks and you're up for it again.
As for the "long run" scenario, if we head out into the wheatbelt and have a 350/400 K's day the Nissan runs so sweet after.
On that note so does my CVO Springer , maybe for the same reasons ?
One of my riding mates has a Mitsubishi Triton ute to tow his caravan.
He has done many mods to it whereas my 2012 Nissan Navara ute is 100% stock bar a K&N stock airbox air cleaner element.
Just last week I was looking into a plug and play unit from Chip Tuning to switch off the EGR system thru' the ECM
( SOUND FAMILIAR FELLOW HARLEY DUDES ??)
Module on the way at $129 posted and delivered
Why ? It is a 2.5 diesel ill handling lump of course , so no need or point in "go faster".
It will give a cleaner response in the exhaust smoke output under certain circumstances , and keep the inlet manifolds and system cleaner.
Better fuel consumption to boot and quicker Turbo spool up they reckon.