Performance cars need to increase the number of cylinders driving the crankshaft, to boost the engine’s performance. When it comes to arranging a six-cylinder engine, they can come in either a straight-line arrangement, called the straight or inline six, or a V-6, when arranged in a V shaped arrangement.
Each engine has its own standpoint and despite the same no of cylinders, each arrangement comes with its own pros and cons.
Straight / Inline Six Engines
Straight six engines are the older configuration out of the two and gained hype after their implementation in the Toyota Supra (1JZ), Nissan GTR (RB26) and the BMW Z4 M40i. Straight six engine got great love and support from the enthusiast in that period due to their distinguishing traits.
PROS
The inline six configuration was and is still valued due to its rather simple design. It is easier to manufacture, as it’s design matches to that of an inline four, with just two more cylinders. It mostly comes with 02 camshafts and 24 valves. It allows mechanics and enthusiasts to understand and work on the engine with much more ease.
Inline six configuration offers unparallel smoothness due to its very arrangement and firing order. I6 engines have a firing order of 1-5-3-6-2-4, which allows a symmetric movement of pistons about the center of the engine. This reduces the number of primary and secondary forces produced in an engine. Due to this factor, some I-6 enthusiasts also claim these engines to have a better sounding exhausts, but that can be termed as a subjective opinion.
An i-6 engine is rather slimmer and tall in the engine bay, hence leaves a considerable amount of space at its sides. It can be used to add up turbos and superchargers, to increase its output even further. This extra space also provides an easier to work environment for mechanics.
CONS
Packing 06 cylinders in a linear arrangement causes this engine to be longer. But their long size makes them harder to fit in engine bays and leaves less space for transmission and the accessory belts.
To adjust to its longer size, usually, its bore size is cut downed a bit and accommodated in increased stroke length. But this causes them to be taller in dimensions now and raises the center of gravity of the front of the car. Which can make the car feel heavier on turns.
V-6 Engines
V-6 engines were later developed, and it offered an arrangement consisting of a set of 3 cylinders offset to each other at 60 or 60 degrees attached to the same crankshaft. This arrangement helped manufactures pack more power in engines with smaller overall form factor.
PROS
A V arrangement of cylinders offers a compact engine, which can be easily packed by a manufacture in their car without much adjustments in the chassis. This allows manufactures to produce performance versions of there normal sedans without much alterations.
CONS
A V-6 engine has unbalanced primary and secondary forces which cause considerable vibrations. These vibrations are then dampened by using counterweights attached to the crankshaft. It adds up to the complexity of the engine.
V-6 engines tend to be complex in their design and are very densely packed. They have increased set of components typically having 04 cam shafts along with 24 valves. This makes them difficult to work on by mechanics.
V-6 engines tend to be a bit wider than the inline engines, hence leave a lesser space around in engine bay to attach turbos and superchargers. Still many manufacturers couple them with even biturbo chargers, but they tend to be difficult to work on by mechanics.
Newer cars have adapted the v-6 configuration due to the huge amount of power they can provide despite their compact form factor. But development has been done in the i-6 engines in the form of Mercedes m256 and BMW’s B58B30 due to the unparallel smoothness offered by this configuration.
