Turbochargers 101

by | Aug 8, 2017 | Forced Induction 101 | 0 comments

How a Turbocharger Works

The word turbocharger is actually an abbreviation of the word turbo-supercharger. Yes, a turbocharger is from the same family as a supercharger – it’s all about “forced induction” (FI), or forcing much more air into the engine to allow for a bigger, controlled and designed explosion in the cylinders resulting is much more power output. A turbocharger is designed to increase the amount of compressed air into an engine. Think of it like this, a turbocharger is, more or less, like a mouth blowing huge amounts of compressed air onto a fire to get a flame going.

Typically, both a turbocharger and supercharger will pump around eight pounds per square inch (8psi) of compressed air into the engine, for the base kits that are provided by aftermarket manufacturers. This is around twice normal atmospheric air pressure which is 14.7psi. This means, you can generally accept to increase performance of an engine, via turbocharging, or supercharging, by around 40% or a little less (there are efficiency losses during the process).  These kits can put out far more power and boost pressure when modified to do so, with the appropriate supporting engine modifications in place.  See our article about this HERE!

Unlike a supercharger which uses ‘engine drive’ to power its turbine, a turbocharger uses exhaust gases to spin its turbine which can spin at speeds of up to 200,000rpm – the more exhaust gases you pump into the turbine, the faster it will spin.  This is why custom exhaust manifolds are built to maximize exhaust pressure.  The pressurised and compressed air is then forced into the cylinders of the engine which, along with more fuel being injected at the same time, produced more power because of the bigger explosion that results.

If you’ve driven an older turbocharged car you have likely felt something called ‘lag’, basically this describes the time it takes for the turbocharger to be spinning fast enough to forcing air into the engine.  The feeling of pressing the throttle and then nothing, nothing, nothing, and then EVERYTHING – all the power in the world comes on. Older turbochargers tended to be larger, which took a lot longer to spin up to efficiency.  Today’s systems are smaller and have reduced friction because and start spinning up sooner, so there is far less lag than the previous generations of these implementations.  Going too small has its drawbacks too, Go too small with the turbocharger can cause problems too as it’s spinning faster than the engine can reasonably apply and manage the increase in air and fuel requirements.  More power is common these, as manufacturers are producing twin-turbo charged vehicles with smaller engines.  Getting big V8 power out of 4 and 6 cylinder engines, with less weight and par better fuel economy to boot!

Of course, the automotive aftermarket has exploited the use of turbochargers, and especially twin-turbocharger setups, to get more than 2X the normal power out of an engine.  It’s not uncommon to see a 200hp engine produce more than 400hp with a twin turbocharger setup.  You can imagine the power that be made with a modern V8 at 400HP…

Stay tuned as we explore Superchargers in more detail soon!


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