Six cylinder engines are considered one of the most reliable and perfectly balanced engines out of all the configurations out there. They provide a lot of power in a wide range of vehicles be it SUV’s or sport sedans. Take for example BMW’s B58 Inline 6 engine. It powers a wide range of their vehicles from the smaller M240i to their humongous SUV, the X7 40i. As a side note, the new generation Toyota Supra also uses the B58 engine from BMW.
But, not all 6 cylinder engines are created equal. The two most common configurations are the Inline 6 and the V6. We also have other types such as Porsche’s flat 6 and Subaru’s boxer engines. In this article, we are going to discuss about the Inline 6 and the V6, the advantages and disadvantages of each and lastly, I will give you my final thoughts.
Inline 6 Explained.
As the name suggests, an inline 6 engine, has six cylinders arranged in a line. It is some times referred to as a straight six engine for the same reason. This type of configuration is synonymous with BMW(s) and the Toyota Supra.
As a matter of fact, the 2JZ engine in the 1st generation Supra is considered the best inline 6 engine ever produced for three main reasons. Durability, power and tunability. With the 2JZ, you can easily squeeze over 500 Horsepower. Throw in a couple of turbos, new air filters and a couple of other mods, you get an engine that can sustain over 1000 Horsepower. What’s even more amazing about this engine is it’s durability. The 2JZ inline 6 has truly stood the test of time with minimal issues.
With Inline 6 engines, tuning is the name of the game. Even with the new B58 and S58 engines from BMW, a simple ECU tuning will have the engine pump out over 50% of their rated power stats.
Apart from the easy modifications of these engines, another major advantage lies in the straight alignment of the engine. Let me explain. Unlike in a V6, an Inline 6 takes less horizontal space since the cylinders are arranged in a line. This leaves room for even more mods on either sides of the engine. Turbo chargers have ample space unlike in a V6 where they are normally placed on top of the engine block or way below the engine bay which makes it a headache to work on.
Aside from having loads of horizontal space, these cars tend to have a longer front end to accommodate for this configuration. It’s the yin and yang of straight 6 engines; you get more horizontal space but in turn you pay for it with a longer bonnet.
Another major advantage of this engine over the V6, is that they have less parts. See, some V6 engines require balance shafts to counter secondary forces and counterweights to counter primary forces in order to reduce engine vibrations. In addition to this, inline 6 engines are less expensive to manufacture as they require one basic engine block and one cylinder head since the cylinders are arrange in a line.
It is also worth noting that inline 6 engines are mostly configured for either rear wheel drive vehicles or all wheel drive vehicles. Making a front wheel drive vehicle with an inline 6 engine is quite tricky due to its architecture. The Inline form makes it much easier for the drive train to channel power to the rear wheels primarily or all wheels in case the car is fitted with two drive shafts.
Due to this reason alone, these engines are mostly found in sporty sedans and race vehicles. Take for example the M3 lineup. Apart from the E96 V8 M3 and the E30 Inline 4 engine, all the other 4 generations of the M3 feature inline 6 engines. In fact, BMW has perfected the art of making inline 6 engines that their latest B58 and S58 engines are currently rated as one of the best in the industry. It is no surprise that Toyota decided to take a page out of BMW’s book in their new generation Supra, which comes with the B58 engine.
V6 Engines Explained.
Unlike straight 6 engines where the cylinders are arranged in one column, in a V6, the engine block is divided into two, with three cylinders on each side. Normally, the cylinders are placed at an angle of 60 or 90 degrees.
V6 engines are way more compact than inline six engines making the front end a bit smaller as compared to the latter. But in turn, you get a tightly squeezed engine bay as the V configuration occupies a large percentage of the horizontal space. As a result, major components of the engine, are re-engineered in a more complex manner as compared to an inline 6 engine.
Take for example a turbocharged V6 engine. Since the Turbos have no space on either side of the engine, they are normally placed on top of the engine in between the V, which is known as a Hot V configuration or slightly hidden away in the engine bay between other components. This makes it a nightmare to work on the turbos in case anything goes wrong.
Power-wise, V6 engines have always produced reliable, tunable and powerful engines. Take for example the Audi S5 and it’s bigger brother, the Audi RS5. Both of these cars feature Turbocharged V6 engines with the difference being that the S5 comes with one Turbo while the RS5 comes with two turbochargers. The power figures in these german sport sedans are quite impressive, with the S5 coming in at 350 Horsepower and the RS5 at 450 Horsepower.
With a simple ECU tune and new air filters both of the engines can produce over 35% of their stated power figures making V6 engines just as tunable as Inline 6 engines.
Generally, V6 engines are a bit more complex and more expensive to produce as compared to an inline 6 engine. This is because of the added parts needed to create a solid V6. As discussed earlier, a V6 engine tends to run a bit rougher due to the vibrations produced by the primary and secondary forces.
To counteract these forces, counterweights are added to the crankshaft and at times balance shafts are also used to counter the unwanted inertia produced by the moving pistons. The bigger the displacement the more counterweights, the engine needs.
Final Thoughts.
While V6 engines tend to be more common that Inline 6, there is no doubt that each of these configurations come with their fair share of pros and cons. If you are looking to buy a 6-cylinder BMW, you may as well forget about a V6 as BMW does not make cars with this configuration.
It is worth noting that V6 engines are also quite versatile as they fit well with front wheel drive vehicles, rear wheel drive vehicles and of course all wheel drive vehicles. I hope this article, has shed some light on some of the confusion that comes with these engines. Leave a comment below if you have any question or suggestion. Also check out our forum to engage with like minded people on various topics such as cars, tech etc. Cheers!!
Nice explanation
The article provides a comprehensive explanation of inline 6 and V6 engines, highlighting their differences. However, I believe the superiority of the V6 engine is subjective. Both engine configurations have their merits, and the choice ultimately depends on factors like performance requirements and vehicle design.
Great insight.
Very insightful
wow!