25/04/2026
𝗧𝗵𝗲 𝗿𝗲𝗮𝘀𝗼𝗻 𝘀𝗼𝗺𝗲 𝗽𝗲𝗼𝗽𝗹𝗲 𝗮𝗰𝗰𝗲𝗽𝘁 𝗯𝗹𝗮𝗰𝗸 𝘀𝗺𝗼𝗸𝗲 𝗶𝘀 𝘀𝗶𝗺𝗽𝗹𝗲.
It is cheaper.
To burn more fuel cleanly, a diesel needs enough air to go with it. Once the turbo, intercooler, injectors, exhaust, or general hardware setup has reached its useful limit, you cannot just keep adding fuel and expect a clean result. The proper answer is often more air, which usually means a better turbo setup, supporting hardware, and proper calibration to match it.
That costs considerably more than a cheap map, so some people choose to accept smoke as the compromise. That is their choice, and this is not about saying the customer is wrong if they understand the compromise and choose to run the car that way.
The problem is pretending there is no compromise or as is with some "tuners" being in denial about there even being a compromise or risk at all!
Black smoke is not magic power, and it is not “just what diesels do”. In tuning terms, it is usually soot from fuel that has only partially combusted, because the engine has been given more fuel than the available air can burn cleanly. That can come from too much fuel, poor control of when that fuel is delivered, or simply pushing the setup beyond the airflow it has available.
There is also a big difference between a little smoke and clouds of smoke. A light haze you might accept and say is normal, especially during spool or a quick transient moment, may be something some people choose to accept. But when it is throwing out thick clouds of black smoke, as is often seen with aggressive PD tuning, that is a much bigger compromise.
At that point, it is impossible to pretend there is no extra heat, no extra stress, and no damage being done over time.
Yes, the car might feel strong. Yes, it might make power. Yes, it might run like that for a while. But “it has not broken yet” is not the same as “it is safe”.
Excessive black smoke often means higher combustion temperatures and higher exhaust gas temperatures. That is the sort of thing you pick up properly with an EGT sensor, not by guessing from the smoke level alone.
High EGT does not always kill an engine instantly. Heat damage can be gradual, with repeated heat cycles and sustained high temperatures taking their toll long before the engine finally shows an obvious fault.
Excessive EGT can crack exhaust manifolds and cylinder heads. Exhaust valves can suffer from the heat and eventually fail. Aluminium parts are often among the first to be affected because aluminium softens and melts at a lower temperature than steel or cast iron.
Pistons, cylinder head areas, valves, turbochargers, manifolds and gaskets can all suffer when heat is pushed too far.
The turbocharger is also under extra stress. More fuel often means more heat and more exhaust energy, which can push the turbo outside its safe working range. That can mean overspeed, bearing wear, cracked housings, sticking VNT mechanisms, boost control issues, or eventual turbo failure.
The exhaust system suffers too. Manifolds, turbine housings, downpipes, flexis, catalytic converters and DPFs, where fitted, are all exposed to more soot and heat. A DPF especially does not enjoy excessive soot loading, and repeated high-temperature events can shorten its life dramatically.
Then there is the oil. Excess soot and heat can contaminate the oil faster, increase wear, and make servicing even more important. On engines already getting older, that extra stress can be the difference between something lasting and something letting go.
This is why copying what someone else has done is not the same as understanding the risk. Just because another car made a certain power figure and survived for a period of time does not mean the same approach is safe, or that no damage is happening in the background.
Every engine has limits. Airflow limits. Turbo limits. Fuel system limits. Cooling limits. Exhaust temperature limits. Once you push beyond those limits, something has to take the punishment.
Accepting black smoke as a compromise is one thing. Pretending black smoke is harmless is another.
If the hardware cannot supply enough air, the clean answer is more air, not just more fuel. If someone chooses the cheaper route and accepts the smoke, that is their decision.
But nobody should be pretending excessive black smoke is fine, harmless, or normal.
This is not just our opinion either. Banks Power has covered this for years: black diesel smoke is soot from fuel that has not fully combusted, adding fuel without enough air raises EGT, and hotter EGTs can damage the engine. In simple terms, more smoke is not free power, it is wasted fuel, heat, soot and risk.
If you want to see the opinion of Gail Banks on the issues, there are are easy to digest links worth reading:-
Banks Power - Turbo-Diesel Fact & Fiction
https://official.bankspower.com/tech_article/turbo-diesel-fact-fiction/
Banks Power - Hopping Up the Turbodiesel
https://official.bankspower.com/magazine/hopping-up-the-turbodiesel/
Banks Power - Why Big Air Density Makes a Big Difference
https://official.bankspower.com/tech_article/why-big-air-density-makes-a-big-difference/
Banks Power - Why EGT is Important
https://official.bankspower.com/tech_article/why-egt-is-important/
Banks Power - Ford 7.3L Power Strokes Need This
https://official.bankspower.com/insider_news/ford-7-3l-power-strokes-need-this/
𝗜 𝘂𝗻𝗱𝗲𝗿𝘀𝘁𝗮𝗻𝗱 𝘁𝗵𝗲𝗿𝗲 𝗮𝗿𝗲 𝗮 𝗻𝘂𝗺𝗯𝗲𝗿 𝗼𝗳 “𝘁𝘂𝗻𝗲𝗿𝘀” 𝘄𝗵𝗼 𝘁𝗵𝗶𝗻𝗸 𝘁𝗵𝗮𝘁 𝗖𝗢𝗔𝗟-𝗹𝗲𝘃𝗲𝗹 𝘀𝗺𝗼𝗸𝗲 𝗶𝘀 𝗵𝗼𝘄 𝗶𝘁’𝘀 𝗱𝗼𝗻𝗲. 𝗟𝗲𝘁’𝘀 𝘀𝗲𝗲 𝘁𝗵𝗲 𝗘𝗚𝗧 𝗹𝗼𝗴𝘀 𝘁𝗼 𝗯𝗮𝗰𝗸 𝘂𝗽 𝘆𝗼𝘂𝗿 𝗰𝗹𝗮𝗶𝗺𝘀. 𝗜 𝗮𝘀𝘀𝘂𝗺𝗲 𝘄𝗵𝗲𝗻 𝘆𝗼𝘂 𝗱𝗼 𝘁𝗵𝗲𝘀𝗲 𝗣𝗗𝟭𝟯𝟬𝘀 𝘆𝗼𝘂 𝗵𝗮𝘃𝗲 𝘀𝗼𝗺𝗲 𝘄𝗮𝘆 𝘁𝗼 𝗱𝗲𝘁𝗲𝗿𝗺𝗶𝗻𝗲 𝗘𝗚𝗧 𝘁𝗲𝗺𝗽𝘀, 𝗼𝗿 𝗮𝗿𝗲 𝘆𝗼𝘂 𝗷𝘂𝘀𝘁 𝘄𝗶𝗻𝗴𝗶𝗻𝗴 𝗶𝘁?
Show us some pics of how you measure the EGT whilst you're at it!
PS I did ask ChatGPT to generate the image, seems to have nit a raw nerve with some, maybe a little too close to the truth lol.
If you want a smoke map, we will do it, just ask for it by the correct name. The death map!
