Intake, compression, power, then exhaust. Every 4-stroke engine ever made – about 80% of all engines currently in existence – function on this principle – even rotary engines. But now ...

We test GM's new variable valve timing system and get dozens of horsepower with not sacrificing and torque. Only at www.hotrod.com, the official website for Hot Rod Magazine.

To get an idea of how quickly today's engines move, look no further than the variable valve system. Read more at Car and Driver.