You’ve heard the word turbocharged engine so many times and you have a basic understanding of how it works, but you’ve never been told how much horsepower it adds.
The answer is more complicated than it appears because adding a turbocharger to an engine usually needs a slew of other modifications.
How much horsepower does a turbocharger add to an engine?
In general, a single turbocharger increases power by 10% to 50%.
How Turbochargers Work
My favorite definition of a turbocharger: Turbocharger: Exhaust gases enter the turbocharger and cause it to spin. Witchcraft occurs, and you speed up.
What makes the phrase even hilarious is that it’s not far off the mark: a turbocharger is a turbine that is pushed by exhaust gases and draws in air to increase airflow via the intake.
More air implies more oxygen in the air-fuel mixture, which means a better fuel burn and more power generated every cycle.
Aside from the turbine, the system includes an intercooler for lowering gas temperatures, a wastegate valve for limiting boost pressure, and a blow-off valve for releasing excess pressure.
How Much Horsepower Does a Turbo Add?
In most cases, a turbocharger adds 10 to 50 percent additional power, as I stated in the introduction.
This is a generality, and the actual increase in power can easily exceed 100%.
At the absolute least, the fuel injection system must be updated for this to happen.
Volkswagen’s 1.9-liter R4 TDI turbocharged diesel engine is my favorite illustration of turbocharger benefits.
There are nearly a dozen different versions of this engine, with power ranging from 74 to 158 horsepower.
Twin-turbo and bi-turbo engines are very popular. On engines with six or more cylinders, twin-turbo refers to two identical turbines that split the load.
A system having a small and a big turbocharger is known as a bi-turbo (or sequential turbo).
The smaller turbo handles low-RPM to reduce turbo-lag, while the second, or both, turbos engage at higher RPM to boost power dramatically.
Then there are engine blocks with six or eight cylinders and a quad-turbo system.
It generates tremendous amounts of power with two bi-turbo configurations — a normally aspirated engine capable of taking a quad-turbo setup can easily double the horsepower.
What Is Turbo Boost?
The turbocharger produces a turbo boost, which is positive pressure. In other words, it denotes the pressure difference between the intake manifold and the surrounding atmosphere.
It is expressed in psi or bar, with higher numbers indicating more power.
Over-boosting, on the other hand, would push the turbocharger and the engine to their limits, resulting in engine banging, overheating, pre-ignition, and component failure.
What Is Turbo Lag?
A turbocharger‘s fundamental working principle is to use exhaust gases as a catalyst to force additional air into the intake. However, this contributes to the turbocharger’s fundamental flaw: turbo lag.
The volume of exhaust gases isn’t large enough to provide a suitable boost when the engine is running at low RPM.
The vehicle will feel as though it had half of its power available, which it does in some ways because it is a normally aspirated engine. The boost kicks in and gives a burst in power only when the RPM is raised to a sufficient level.
Turbocharged power is always offset by turbo lag in a single-turbine engine. The larger the turbine, the more pressure is needed before it can begin boosting, resulting in a longer turbo lag.
Small turbines, on the other hand, will activate just above idle RPM but will not be able to give enough boost to generate a lot of power.
When you take your foot off the gas, which is usual when braking and moving gears, turbo lag develops. There are, however, a couple of workarounds.
The heel-toe approach is the first strategy to reduce turbo big. Apply the brakes first, then the clutch. When the transmission is disengaged, you can downshift by stepping on the gas with the heel of your right foot.
When you let go of the clutch, keep your foot on the gas pedal and the turbo boost will kick in sooner.
Heel-toe isn’t possible in many automobiles, and depending on your seating position, it might be quite difficult.
There is a simpler method that achieves the same effects, but it takes a little longer.
First, you take a rest until you’ve decelerated enough. Engage the clutch, and step on the gas once or twice with your right foot as you transfer gears.
Both approaches, of course, necessitate the employment of a manual gearbox.
They’re mostly intended to assist you in completing an overtake while you’re decelerating towards a vehicle yet see an opening to pass it.
Rather than wasting time due to turbo lag, the automobile will be ready to give full power as soon as the left lane clears.
When driving uphill, I utilize both strategies frequently. I need to break when there’s a sharp corner, but I don’t want to lose the power I need to keep going.
By reducing turbo lag, I can maintain enough power to safely navigate the corner and increase my speed if necessary.
The Drawbacks of a Turbocharger
Turbochargers have numerous advantages.
The only true disadvantage of turbochargers is the increased engine complexity. The more parts you add, the more likely they are to break.
With a single-turbocharger configuration, this isn’t an issue, but if a car has two or four turbines, consider how much it will cost to repair or replace them.
FAQs About how much horsepower does a turbocharger adds to an engine.
Do turbos make more power?
Turbochargers, together with superchargers, are the best means to boost an engine’s power without expanding its displacement or introducing excessive tolerances that would drive up manufacturing costs.
At what RPM do turbos kick in?
At 2,000 RPM, enough exhaust pressure is generated to spin the turbine and create a turbo boost.
The exact RPM is determined by the turbine’s size; smaller turbines engage sooner, while larger turbines are frequently configured in a bi-turbo configuration, with a smaller turbine producing power at low RPM.
Are turbos bad for your engine?
Turbochargers installed at the factory are not harmful to your engine. The engine has been built to handle the turbo boost without being damaged by the manufacturer.
Modifying a factory turbocharger or adding a bespoke turbocharger, on the other hand, can damage the engine by pushing it beyond its tolerance thresholds.
Does a twin-turbo make a car faster?
Yes, it does. Split exhaust manifolds are used in six- and eight-cylinder engines and each produces enough exhaust gases to fuel one turbocharger, which then generates enough boost to supply all of the cylinders.
Although the power boost is similar to that of single-turbo engines in terms of percentage, twin-turbo engines offer significantly greater power in terms of numbers.
Summary
Turbochargers have become a must-have for engines with smaller displacements, greatly increasing their power and making them more useful on the open road.
Turbochargers aren’t required for larger inline-6, V6, and V8 engines, although they can be added in pairs for a big power boost.
If you’re looking at automobile deals and aren’t sure if you need a turbocharged engine, any 4-cylinder engine is a good choice.
For all except the largest V8 options, a turbocharger is particularly useful in SUVs and trucks.
