Revolutions Per Second (RPS)

Written By Scott Clayton

Blowing Minds By Reducing The Denominator

The problem I see with Revolutions Per Minute (RPM) is, it’s too much divided by too much. It’s too large of an amount divided by too long of a time. If you are counting in the thousands, wouldn’t you be able to be reduced by something? Seconds seems logical.

If your tachometer reads in Revolutions Per Second (RPS), we would have a better appreciation for our engines. Example, a typical 600cc sportbike redlines around 16,000 revolutions per minute, if we convert that to RPS, it’s 266.67! Two hundred sixty-six revolutions per second!? How does all that metal stay inside the engine cases? A typical cyclist pedals a bicycle around 60 to 100 revolutions per minute. That is one each second, to 1.67 revolutions per second. Can you imagine pedaling at 17 revolutions per second just to idle your engine?

Here are some examples of vehicle’s redlines:

  • 16,500 RPM (275.0 revolutions per second): Yamaha R6 (0.6L)

  • 13,750 RPM (229.1 revolutions per second): Yamaha R1 (1L)

  • 9,250 RPM (154.1 revolutions per second): Ferrari LaFerrari (6.3L)

  • 9,000 RPM (150.0 revolution per second): Porsche GT3 (4.0L), Ferrari 458 (4.5L), Honda S2000 (2.0L)

  • 7,000 RPM (116.6 revolutions per second): Chevrolet C6 Corvette Z06 (7.0L)

  • 6,000 RPM (100.0 revolutions per second): Chevrolet Silverado (6.2L)

  • 2,000 RPM (33.3 revolutions per second): typical car/truck cruising speed

  • 1,000 RPM (16.6 revolutions per second): typical idling speed

We would have to rearrange the way we display our tachometers. But I’m alright with that! No one wants to read 33.3 revolutions per second for an idle. We’d probably just call it, 35. We could always just write the Canadian version on the inside, HA-HA.

Even though the twelve cylinder LaFerrari and the Four cylinder Honda S2000 have roughly the same liters per cylinder (Ferrari .525L vs. Honda .500L). Assuming they both have an even firing order, unlike the R1’s (270-180-90-180 degrees) or the RC51’s (270-450 degrees). The LaFerrari’s engine produces power every 60 degrees of crankshaft rotation, whereas the S2000’s engine produces power every 180 degrees of crankshaft rotation. It’s also a packaging problem for the Honda, you can’t fit a twelve cylinder engine into a four cylinder engine bay.

A Yamaha R1 Crossplane 4 with an uneven firing order of 270-180-90-180 degrees.

So if we can’t spin the crankshaft with our legs fast enough to idle an engine, what about the valves and springs? They spin, only half the speed. How about pushing down on the valves 8.3 times per second, just to idle. Can you even click a mouse that fast? Valves opening and closing at 14,000 revolutions per Minute, is 116.6 per Second. Here are some videos of BMW’s S1000RR (1.0L flat plane 4 cylinder):

Scott Clayton