Strictly defined, compression ratio is the total volume above the piston at bottom dead center (BDC), divided by the total volume above the piston at top dead center (TDC). First, let's look at the ...

No compression-ratio calculation is worth spit if the numbers used to calculate it are wrong. In the old days, a lot of the chamber volumes published for stock heads were NHRA minimum-legal blueprint ...

You've heard the term compression ratio before, but have you ever wondered exactly what it means? Well, it's time to explain exactly what compression ratio is, and why every carmaker is now obsessed ...

A gasoline piston engine that can dynamically change its compression ratio —that is, the amount by which the piston squeezes the fuel-air mixture in the cylinder—has long been a holy grail of engine ...

We may receive a commission on purchases made from links. While browsing auto repair and maintenance tools at your local parts store, you've likely come across compression testers like the Orion Motor ...

While we like to think of 2002 as being part of a high-tech age, our beloved internal combustion engine hasn't really changed much in the last 50 years. We're still using pushrods and overhead valves, ...

Increasing an engine’s compression ratio is a proven way of unlocking extra horsepower, but there’s a point of diminishing returns. The team at Garage 54, the Russian mechanics who built a V16 using ...

For more than a century now, automotive engineers have struggled with an unavoidable balancing act when it comes to engine compression. Now, thanks to an innovation from Infiniti, they may get to ...

We may receive a commission on purchases made from links. I have been working on my own vehicles for almost 40 years and in that time have accumulated a sizable collection of tools. The bulk of them ...