Innovation is nowhere near a perfect science. Whenever you start to think outside the box you run the risk of failing, as by definition, you are in uncharted territory. Sometimes, the failure is early on in the cycle as an idea immediately doesn’t pan out, and sometimes the failure is much later in the development process, as unaccounted-for variables come into play. This video shows seven ingenious engine technologies that didn’t last very long for one reason or another, be it because of rules changes, or other technologies improving to the point of making the innovative ideas obsolete. We’re going to address the five we found most interesting.

Starting off is the Honda NR500, in which Honda devolved oval cylinders and pistons to cram eight cylinders-worth of valves and spark plugs into a V4, four-stroke that met the letter of the MotoGP rules of the time. The goal was to match the power of the field of two-stroke engines, which they couldn’t do with a standard four-stroke four cylinder engine. The innovative design lasted three seasons before Honda gave in and developed a two-stroke to compete with.

The Honda NR500 was a rule-bending innovation trying to get high-revving V8 power out of a four-stroke four cylinder engine. With eight valves, two spark plugs, and two connecting rods per cylinder, this V4 engine was pushing limits. Ultimately, Honda scrapped the project after three seasons and joined the field with a two-stroke.

Next is Volkswagen’s G-Lader supercharger. A scroll-type supercharger that was originally patented in 1905, Volkswagen debuted it in the 1980s as a maintenance-free supercharger. Resembling a spiral version of the Wankel rotary, the complicated unit was dogged with issues. Despite being advertised as maintenance-free–or potentially because of it–the G-Lader experienced a high failure rate unless a fairly intensive maintenance program was adhered to, resulting in the technology being abandoned.

The Cadillac V8-6-4 was simply ahead of its time, as we’ve seen this technology, or a variant of it, return as the “Displacement-on-Demand” system used in some of today’s GM engines. A 368 cubic-inch L61 engine–which was a de-bored 425–the V8-6-4 engine had solenoids attached to the rocker arms would disengage the rocker arms from the pushrods, leaving only six or four cylinders with a functioning valvetrain. Unfortunately the required electronics weren’t powerful enough at the time, and the system was unresponsive and often behind the action curve.

While the Mazda Rotary is still an extremely popular powerplant and has been elevated to cult status in the sport compact world, it can be considered a failure on the commercial stage. However, its failure really isn’t one of engineering, but rather one of governmental oversight, as the innovative Wankel design couldn’t keep up with rapidly-changing emissions standards. Even Mazda’s second commercial attempt at the rotary with the Renesis version, while meeting with critical acclaim, only lasted 10 model-years before it was removed from the commercial line.

The Cadillac V8-6-4 engine was a solid idea, which simply was ahead of its time, as the supporting electronics simply couldn’t keep pace with real-world conditions. However, it did have a cool display that showed you how many cylinders were active at any given time.

The final “failure” on this video’s list is extremely arguable as an automotive failure, as air-cooled engines have been used in production automobiles for a huge chunk of time – almost 100 years – and perform extremely well in their given applications. The only way you could argue that the technology “failed” is if you skew your definition of failure to include only automotive applications, and technology that in no longer in commercial use (and ignore the current motorcycle and aviation applications of air-cooled engines). This one seriously has us scratching our heads.

What do you think? Does an outdated or obsolete technology constitute a “failure”? Are there any that the video missed? Let us know in the comments below!