There's A Good Reason Semi Trucks Don't Use V8s

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V8 engines are among our favorites. They make large powerfulness and sound that is, successful nan vernacular of Boston, wicked awesome. It's only earthy to deliberation that specified large engines would powerfulness nan large semi trucks that carrier astir cargo successful nan U.S., but that isn't true. Instead, you're much apt to find an inline-6 nether nan hood of astir modern semis. 

There are immoderate important reasons why V8s person fallen retired of favour successful trucking. A V8 makes awesome horsepower, but towing dense loads is each astir torque. The inline-6 engines powering astir modern semis make betwixt 400 and 600 horsepower. That's not overmuch much powerfulness than a well-equipped pickup motortruck these days, and is apt each nan horsepower you really request anyway. However, astir pickups don't make anyplace adjacent nan 1,000 to 2,000 pound-feet of torque that semi engines do. Big displacement successful nan 13 to 16-liter range, turbocharging, and diesel powerfulness maximize torque, and it shows successful those four-digit figures.

Another facet is that successful nan U.S., semis are typically constricted to a maximum weight of 80,000 lbs. Scania makes a 16.4-liter V8 producing 2,350 lb-ft utilized successful Europe, but galore of those countries let heavier loads than we do. A smaller inline-6 tin grip lighter American loads conscionable fine.

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Some opportunity that nan inline-6 motor configuration itself inherently favors torque complete horsepower, but this isn't wholly true. A longer stroke, which is nan region nan piston travels wrong nan cylinder, arsenic good arsenic larger cylinders overall, is what produces much torque, sloppy of cylinder configuration. However, nan tall, skinny creation of an inline-6 makes it easier to creation 1 pinch a agelong stroke. Giving a V8 much changeable will make it wider arsenic good arsenic taller, which intends a tighter fresh nether nan hood. A semi has room to spare for a long, gangly inline-6, but will ever beryllium constricted successful really wide it tin be.

One trade-off of an motor pinch a agelong changeable is that it can't move accelerated RPMs for illustration a high-horsepower motor pinch a short stroke. Again, what whitethorn look to beryllium a disadvantage is really a spot successful this application. Lower RPMs put little strain connected nan engine, making it much reliable and reducing wide operating costs.

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The basal quality of an inline-6 is simpler than a V8. There's only 1 cylinder head, not two, truthful it has less parts. It's besides easier to entree and activity on, reducing some attraction costs and nan clip nan motortruck is disconnected nan road. All this, positive its low-revving nature, makes nan motor somewhat much substance businesslike than a higher-revving V8. It's not overmuch much efficient, but erstwhile you're talking six to 8 MPG, each small spot helps and makes a large quality complete thousands of miles.

The last nail successful nan V8's coffin was progressively strict emanation regulations for semis. It's easier to get a smaller displacement inline-6 to comply than a bigger V8, truthful that's what astir manufacturers chose to do. In contrast, immoderate companies for illustration Caterpillar simply discontinue producing semi-trucks, focusing alternatively connected off-highway applications. While electric options like nan Tesla Semi whitethorn play a domiciled successful nan future, nan inline-6 remains nan workhorse of American trucking for now.