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V6 vs. Straight 6 & Inline 6: Which Is Better?

Andrew Cilio
By: 

Andrew Cilio

 / Jan 18 2023
V6 vs. Straight 6 & Inline 6: Which Is Better?

In general, V6 engines are better for vehicles with front-wheel drive that don't have enough room for six inline cylinders, but straight-six engines tend to have better performance with lower vibrations.

The key difference between V6 and straight-six (or inline-six) engines is the arrangement of their six cylinders. Traditionally, the cylinders (along with their spark plugs) were arranged in a straight line, making for a long but powerful engine. The V-shaped engine layout of two rows of three cylinders that gives a V6 its name allows engines to be built smaller while maintaining six-cylinder power.

If you think the difference between these two designs starts and ends with the shape and size of the engine, think again. Both designs have unique advantages, and you'll find that many truck owners and gearheads are coming back around to the straight-six these days. If you're undecided, we'll help you uncover which side of the V6 vs. straight-six debate you want to stand on.

Table of Contents
  1. What Is a Straight 6 (or Inline 6) Engine?
  2. What Is a V6 Engine?
  3. V6 vs. Straight 6: Key Differences
  4. V6 vs. Straight 6: Which Is Better?
  5. FAQs
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What Is a Straight 6 (or Inline 6) Engine?

Straight-six engines (also called inline-six engines) are engines where six cylinders are arranged in a straight line across the crankcase, typically from front to back. To accommodate the length of the engine, in some vehicles, the crankshaft is positioned horizontally so it runs parallel to the front of the car instead of perpendicular, which is called a transverse engine.

The straight-six engine was an innovation on the straight-four engine. The extra two cylinders obviously made it significantly longer, paving the way for the more spatially efficient V6 down the road.

Straight 6 Engine Specs

To set up our straight- / inline-six vs. V6 comparison, we'll break each down by a few different essential categories: firing order, size and position, and movement.

Firing Order

Inline 6 Firing Order

The beauty of the straight-six engine is its simplicity and symmetry, which is reflected in the firing order of the cylinders.

Picture the six cylinders running in a straight line from the front of the vehicle toward the back, numbered 1-6. As the engine runs, they fire in the sequence of 1-5-3-6-2-4, with 1/6, 5/2, and 3/4 mirroring each other. So, as 1/6 reach their peak, 5/2 approach the peak as 3/4 are dropping. If you could watch from the side, it would look like a wave with 1, 2, and then 3 rising to the top at the same time 6, 5, and then 4 do, respectively.

Size and Position

Unfortunately, that same simplicity of design is also the straight-six's biggest drawback. That single row of cylinders makes for a long, cumbersome engine block that can be tough to fit under a smaller vehicle's hood or accommodate front-wheel drive.

The vertical movement of the pistons also means the engine is tall and narrow, which also means it has a high center of gravity. In a vacuum, this translates to a less balanced drive, but a vehicle can be designed to account for this so it's not likely to be a noticeable issue for most drivers these days.

Movement

Another benefit of the straight-six's single row of vertical cylinders firing in a mirrored order is that it naturally promotes balance and keeps wasted movement to a minimum. There's no need to counterbalance any side-to-side engine movement to reduce vibrations.

Benefits of a Straight 6 Engine

The straight-six engine is starting to regain its former glory—for good reason. It may be big, bulky, and relatively simplistic, but those characteristics carry some pretty clear benefits.

  • Reliability: Inline cylinder engines stood the test of time in part for their reliable performance and durability
  • Stability: Vertical firing means less horizontal motion and lower vibrations.
  • Ease of Maintenance: With one bare-bones set of valvetrain components, there's less to go wrong on a straight-six and when something does need work, it's easier to repair.

Drawbacks of a Straight 6 Engine

For all the benefits of a straight-six, there are reasons the V6 was developed to replace it. Here are a few drawbacks V6 engines were meant to correct.

  • Cumbersome: The long crankshaft of a straight-six means six inline cylinders are either off the table for smaller vehicles or would have to reduce interior space to accommodate them.
  • Not Ideal for Front-Wheel-Drive: The length of a straight-six engine also means it's tough to make work for vehicles with front-wheel drive.
  • Less Balanced: Though this is a minor, correctible drawback, in theory, an inline engine's higher center of gravity slightly reduces its handling.

Pros:

Cons:

Reliability

Cumbersome

Stability

Not ideal for front-wheel drive

Ease of maintenance

Less balanced

What Is a V6 Engine?

A V6 engine is an engine with six cylinders arranged in two rows of three generally laid out in a V-shaped formation. As an innovation on the traditional straight-six design, this layout was designed to make engines more compact without sacrificing performance.

V6 engines became popular choices for manufacturers of everything from sports cars to mid-size sedans to full-size trucks and have some distinct features and advantages

V6 Engine Specs

To dig into the differences between V6 and straight-six engines, we'll look at a few key specs that set the two apart.

Firing Order

V6 Firing Order

Typically, the firing order of a V6 engine alternates from left to right starting at the front (either on the left or the right, generally depending on which option is nearer to the crankshaft's front). For example, starting at the front of the vehicle, a GM V6's order would be 1-3-5 on the left and 2-4-5 on the right, a consecutive 1-6 zigzag.

On other V6 engines, the order may run front to back on one side and then front to back on the other. A Ford V6, for example, would be ordered 1-2-3 from front to back on the right side and 4-5-6 from front to back on the left side.

Size and Position

Comparable to a traditional inline-four, the layout of a V6 engine makes it more compact, so it tends to be a better option for a wider range of body sizes that might not otherwise fit a straight-six engine. It's like trying to fit a hamburger in a lunchbox instead of a 12" sub. V6 engine blocks are also positioned lower toward the ground, which in turn creates a lower center of gravity that improves handling.

Movement

Because the two rows of cylinders in V6 engines fire at opposing angles with long strokes, they create more side-to-side movement. There are balancing shafts with counterweights in the engine meant to reduce this movement, but they can't counteract 100% of the vibrations created by the firing cylinders.

Benefits of a V6 Engine

These details may sound great, but what do they mean in practice? The size and position of a V6 engine provide the following benefits:

  • Compact: V6 engines have a smaller footprint, opening up more space for mods like turbochargers.
  • Balanced: With its lower position, a V6 engine has a lower center of gravity and more even weight distribution.
  • Versatile:  The "V" configuration of a V6 engine allows manufacturers to drop a six-cylinder engine into a vehicle that otherwise would only have been able to accommodate a four-cylinder inline engine. Its shorter size also allows it to be used in a front-wheel-drive vehicle.

Drawbacks of a V6 Engine

V6 engines may be more widely driven than straight-sixes, but they do come with a few drawbacks.

  • Maintenance Complexity: With double the amount of valvetrain components to accommodate the V6 structure's two cylinder banks, there are more parts of a V6 to repair and maintain.
  • More Vibrations: The construction of a V6 engine is less balanced than a straight-six, leaving more room for movement from the cylinders and leading to increased vibrations throughout the crankshaft.
  • Less Reliable: For those who rely on power performance, V6 engines aren't generally as prized for longevity as straight-six engines.

Pros:

Cons:

Compact

Maintenance complexity

Balance

More vibrations

Versatile

Less reliable

V6 vs. Straight 6: Key Differences

So you know that V6 engines are shaped like a V and straight-six engines form a straight line—but what's all that really mean for you, the driver? If you're looking for the real key differences between V6 and straight-six engines tied up in a neat package, here's the long and short of it.

V6 vs. I6 Key Differences

V6 vs. Straight 6: Which Is Better?

If you're still undecided on the V6 vs. straight-six debate, consider that most die-hard performance fanatics seem to fall on the straight-six side—but that doesn't make it a clear winner.

  • From a pure performance perspective, inline engines have the better blend of performance, reliability, and ease of repairing or replacing engine components.
  • From a production standpoint, V6 engines tend to make more sense for adding six-cylinder power to vehicles with maximum interior space and front-wheel drive.

Frequently Asked Questions

Is a Straight 6 the Same as a V6?

Straight-six (or inline-six) and V6 engines both have six cylinders, but they are arranged very differently. Straight-six engines are long, tall, and narrow, with the cylinders aligned in a single row, typically running from front to back. V6 engines are more compact, with two rows of three cylinders angled in a V shape.

Is a Straight 6 More Powerful Than a V6?

Straight-six engines are known to be more performance-friendly than V6 engines, offering more reliable power and greater torque.

What Does V6 Mean?

V6 refers to the V-shaped arrangement of six cylinders on an engine, with the cylinders angled downward at typically 60 or 90 degrees. By contrast, in a straight-six or inline-six engine, the six cylinders are arranged vertically in a single straight line.

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