Are We All Using The Word 'Intercooler' Wrong?

See the shiny looking part sticking out of the Audi TT above? You’d probably be tempted to call it an intercooler. But, if we want to be pedantic about it for a moment, it technically isn’t.

Before we go any further though, let’s remind ourselves of what these devices actually do. The job of what we usually refer to as an intercooler is to cool down the air that’s just left the turbocharger or supercharger. Cooler air means more oxygen entering your engine, burning more fuel and increasing performance.

There is an argument, however, for an ‘intercooler’ used in an automotive application to actually be referred to as an ‘aftercooler’. Why? The answer is to do with planes, oddly enough.

Some piston aircraft engines feature ‘staged’ turbochargers (typically two, but sometimes more), with one forcing air into another, which then forces air into the engine. It’s the kind of turbocharging that Christopher Nolan would dig, but it also leads to an undesired build up in both heat and pressure.

The solution is to place a cooling device between the turbochargers. Given its location, it’s referred to as an ‘intercooler’. You’d then have another cooler placed after the last turbo and before the engine, called - you guessed it - an ‘aftercooler’.

A car’s intercooler? That’s after the last stage of turbocharging too, hence why some consider it to be correct to call it an aftercooler. The counter-argument is that the ‘inter’ prefix still works, since the part is sitting between two things - the turbocharger and the engine. Plus, since the staged turbocharging is extremely rare in the automotive world (it’s better suited for planes where turbo lag is less of an issue), there’s no need to distinguish between something being an intercooler or aftercooler.

In fact, intercoolers and charge coolers themselves are no different - it’s all about the placement, so there’s a rationale for using the catch-all term of ‘charge air cooler‘. However, the word intercooler has become so widely used by car makers, automotive journalists, petrolheads, and manufacturers themselves like Forge, it’s likely to remain synonymous with charger air coolers in cars for the foreseeable future.

What do you call these devices, and why? At the risk of opening a big can of worms, we’d like to know your thoughts in the comments!