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Smoke Responsibly

Diesel Pollution and its Consequences


Diesel has a unique feature - the ability to blow thick clouds of dark, black smoke. The intent of this article is not discuss the environmental impacts of such behavior, but rather to point out the harm that, collectively, we are are doing to ourselves and our passion for all things diesel. If you make it to the bottom of the page, you will (hopefully) realize that our intentions are to preserve the freedoms that we have left regarding the diesel marketplace. When smoke or "coal" is blasted into the atmosphere purposely, excessively, or for the purpose of provoking a public reaction, it does nothing but harm the future of this industry, slow it's growth, and give politicians and activists additional flak in the battle against diesels.


Black Smoke - What it Means

Excessive smoke indicates a rich air-to-fuel ratio. That is, you do not have the quantity of air to match the quantity of fuel entering the cylinders and the mixture is stoichiometrically incorrect. For street driven trucks, it is simply a sign that you need more air delivery to take advantage of the fuel available. A well balanced performance setup should match fuel and airflow for a virtually smoke free exhaust stream under full load. Considering that excessive smoke can cause exhaust gas temperatures (EGTs) to spike into the danger zone, a truck that billows smoke is less capable, useful, and practical as one that can keep the exhaust clean under full load. At the end of the day, the soot billowing out of your exhaust is nothing more than a less-than-ideal performance setup for an average street vehicle.


That being said, a "puff" or light haze of dark smoke emitted from the tailpipe of a diesel engine under load is normal for many pickups. This is typically related to turbocharger lag, the time required for the turbocharger to build pressure (spool) relative to changing engine load. If the smoke is excessive or persists when the engine is lightly or moderately loaded, a problem may be present and an owner may want to investigate the condition further. A properly tuned, properly maintained engine should not smoke excessively; this is true for even a high mileage motor.


All 2008 and newer trucks should not smoke, regardless of driving conditions. The 2008+ Duramax (Chevrolet/GMC), Power Stroke (Ford), and Cummins (Ram) powered pickups are equipped with a diesel particulate filter, which can achieve 90% - 100% efficiency in capturing harmful particulate matter from diesel exhaust.

Particulate Emissions are a Root Cause of Stricter Federal Emissions Regulations

Many continue to complain when the manufacturers introduce new emissions components for their pickups. EGR systems inherently lower performance and have contributed to reduced reliability. Diesel particulate filters (DPF) hurt fuel economy and often clog, sending owners to their local repair facility. The latest addition, slective catalytic reduction (SCR), requires owners to purchase diesel exhaust fluid (DEF) and maintain the DEF level at all times. Not only do these components complicate the trucks operation, but the cost of the components themselves (which can be thousands of dollars) increases the cost of the truck. While there are many factors, both scientific and political, that have led to stricter emissions regulations of diesel engines, purposely modifying a truck to emit clouds of soot is certainly not helping our cause.


Elected political figures are behind initiatives that require automakers to reduce diesel emissions. When the public, who may or may not understand the benefits of diesel, see mass amounts of particulates being emitted by diesel powered trucks they are obviously going to be dissatisfied. And lets not forget that diesel emission regulations affect the entire infrastructure of our nation. The EPA is not just cracking down on light duty diesel powered pickups, commercial medium and heavy duty trucks are also under attack. The hard working men and women who keep the shelves of your local stores stocked with goods are facing increased operating costs, and this has been particularly difficult on owner operators. Many ports are imposing age restrictions on large trucks, denying older tractors entrance into key shipping centers. Small businesses are finding it difficult to remain competitive in the trucking industry, since they do not have the capital to retrofit or purchase new trucks like larger fleets do. And don't forget that increased operating costs for truckers translates into increased prices for consumers. While the abuse of performance products is not the sole reason that diesel emissions continue to become stricter, it is certainly not helping our case as diesel owners who want to take full advantage of the efficiency of our trucks . Why did it take so long for 1/2 ton diesels to finally hit the showroom floor? Strict emissions regulations certainly created many obstacles for automakers.

Crackdown on the Aftermarket

Ever noticed that many performance products come with a “off-road use only” disclaimer? EGR and DPF delete kits, for example, are not street legal. If owners continue to abuse the use of performance items for the sole purpose of rolling coal through town, a crackdown on these components by government bodies is inevitable. It ultimately becomes the responsibility of diesel owners not to abuse the availability of such items. Edge and Superchips, two major manufacturers of tuning devices for diesel pickups, seem to have voluntarily removed all their “Racing Products” from their respective product lineups. We speculate that these companies received criticism and/or warnings from regulators, but we have been unable to confirm this from a reliable source. Their announcement states that “Unfortunately, we believe a portion of dealers and consumers are exploiting the intended use of these products which has a negative impact on the future of this industry”. We support all that the aftermarket has to offer, and believe that it is the responsibility of owners to use these products in a manner that does not damage the reputation of the diesel cycle. There are a variety of products available that should not be used on the street and nobody wants to see performance companies receiving flak for abuse.

Diesel Soot is a Carcinogen

The World Health Organization (WHO) announced on June 12th, 2012 that they now classify diesel exhaust as a known carcinogen (previously classified as a probable carcinogen). Sufficient evidence was provided by the International Agency for Research on Cancer (IARC) to prove that diesel exhaust exposure can cause lung cancer. This makes it even more important that owners “smoke responsibly”, if not for health reasons, but for the sake of not giving regulators anymore ammunition during the next round of emissions discussions. Many videos of diesel owners blowing smoke on bystanders or in open car windows have become popular on You Tube. These are the sort of irresponsible actions that negatively impact our industry and give diesels a poor reputation within the public eye.


This article is not an attempt to convince you not to modify your diesel. The team at Diesel Hub are huge enthusiasts and supporters of diesel performance, and do not want this industry to be further impacted.