WTF Is Rolling Coal?

Also known as 'Prius repellent', rolling coal has become a craze in the diesel truck community. Here's how it works
WTF Is Rolling Coal?

Originally only found in truck-based motorsport, rolling coal has become a modification found in many road-going trucks in a stand against any form of eco-friendly motoring. These systems have now also made their way into the modified car scene, so here’s a quick explanation of what is going on behind the scenes of these smoke-billowing crowd-pleasers.

Rolling coal is the combination of throwing a large amount of fuel into the engine’s cylinders along with the bypassing or removal of the emission control devices further downstream. By flicking a switch rigged up on-board to the ECU, the air/fuel mixture can be made extremely rich, pushing it past the optimum combustion condition called the Stoichiometric ratio. This richer mixture (below 14.6:1) subsequently creates more particulates within the exhaust gases, otherwise known as soot.

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The EGR (exhaust gas recirculation) valve controls the amount of exhaust gases that are recycled back to the combustion chamber to help absorb unwanted emissions from the post-combustion gases. However, in rolling coal setups, the EGR valve can be bypassed using aftermarket kits. Couple that with the removal of the catalytic converters within the exhaust system and you have virtually no control over the emissions coming from the engine, thus resulting in huge billows of soot emanating from the tail pipes.

To finish off potentially the most-obnoxious modification known to man, straight-piped ‘smoke stacks’ can be fabricated directly behind the truck’s cabin or even as straight-up chimneys protruding from the bonnet, making sure there is no dilution of the exhaust gases immediately after combustion.

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Originating from the sport of truck pulls – where large trucks compete to see who can drag the heaviest load – rolling coal was designed as a grand show of horsepower and torque in these most American of gladiatorial battles. But the trend has swiftly made its way into road trucks.

Unfortunately, the US Government deems any form of emission-control tampering illegal under the Clean Air Act. If all the videos on YouTube are to be believed, it seems most rolling coal systems are normally only used in rare Prius-scaring situations, therefore switching off any bypass valves should see a truck successfully complete an emissions test. So just don’t get caught smoking out some poor hybrid driver by the local law enforcement and you’ll be just fine!

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Comments

Anonymous

[DELETED]

11/12/2016 - 14:12 |
0 | 2
Anonymous

In reply to by Anonymous (not verified)

Qian Li Nissan 420sx

11/12/2016 - 14:15 |
2 | 2
Deadpool (Cam's much sexier twin) (Official Demon Fangirl)

In reply to by Anonymous (not verified)

Mr.PurpleV12

11/12/2016 - 14:15 |
4 | 0
495QED

In reply to by Anonymous (not verified)

Mr.PurpleV12

11/12/2016 - 14:16 |
4 | 0
iCypher(Joel Chan)

In reply to by Anonymous (not verified)

Qian Li

11/12/2016 - 14:16 |
2 | 2
Michael R. T. Jensen

In reply to by Anonymous (not verified)

[DELETED]

11/12/2016 - 14:17 |
0 | 0
Kaede Hong

“Video via Car Crash Compilation HQ”
Steals a video, gets credit from CarThrottle

11/12/2016 - 14:16 |
16 | 4
OgierJr (Ford Powered) (Hoof-Hearted)

In reply to by Kaede Hong

They stole it from CarThrottle, too.

11/13/2016 - 00:37 |
0 | 0
Michael R. T. Jensen

Rolling coal is a hugely stupid thing, where people in oversized trucks like to waste money dumping excess fuel into their engines. They like the decreased performance and the abuse their engine and exhaust system takes, “‘cause I’m cool bro”.

11/12/2016 - 14:16 |
370 | 16

Totally gunks up your oil much faster too.

11/12/2016 - 14:26 |
70 | 2

Some people like to roll coal,they’re a different part of car culture,you may not like it but some people do

11/12/2016 - 15:43 |
18 | 22

So it’s like vaping pretty much

11/12/2016 - 17:13 |
12 | 0

Yeah man, also the polution problem… Eco-Regulations should exist for custom cars too, not only for stock factory cars

11/12/2016 - 17:50 |
16 | 2
iCypher(Joel Chan)

I can never, for the life of me, understand what those unintelligent(In a sense) ‘Coal Rollers’ think when they try and engulf a Prius in Diesel Soot(Which they usually Succeed in Anyway), I mean, I know why, but I can’t understand how the Prius plays such a big part in it. Its like, so, odd.

11/12/2016 - 14:19 |
20 | 4
Anonymous

If you have so much extra fumes coming out, that means they are taking up excessive space in the combustion chamber, which means you’re loosing power. Rolling coal is rice in my opinion because it was inspired by a motorsport but only is a cosmetic modification.

11/12/2016 - 14:20 |
28 | 2
nobody 1
11/12/2016 - 14:26 |
58 | 4
WTF Is Rolling Coal?
Straight6Unicorn95

In reply to by nobody 1

Boom! INstant cancer. this guy died 4 days later

11/14/2016 - 00:46 |
2 | 2
Valanti Demetriades
11/12/2016 - 14:29 |
8 | 12
Darth Imperius/Anthony🇭🇷

I somehow kinda like it. Especially that Cummins swapped Mustang.

11/12/2016 - 14:32 |
8 | 12

If you wish to Google it they call it a cumstang

11/12/2016 - 15:34 |
0 | 0
Black Phillip

The black smoke that pours out of the tailpipe is mostly testosterone.

11/12/2016 - 14:43 |
48 | 2
Rally Maniac (ThePeugeotGuy)

Its also incredibly stupid. God bless ‘Murica

11/12/2016 - 14:53 |
12 | 0