Turbos vs. Superchargers
Author: Carly Augustynowicz
February 1, 2021
Even if you’re an all-motor type of enthusiast, there’s no denying that those boosted car noises are music to our ears. In fact, I bet you just made some turbo noises in your head and smirked a little bit. Whether you want to boost your car but don't know where to start, or you're just curious about the difference between turbochargers and superchargers, we’ll cover the basics of turbos and superchargers with the pros and cons of each.
- Important Definitions
- Forced Induction: What does it mean?
- Turbocharger Pros
- Turbocharger Cons
- Supercharger Pros
- Supercharger Cons
- What should I boost my car with?
Turbo Lag: Occurs when your turbo is waiting for those exhaust gases to spool the turbo and pull in air from outside.
Intercooler: A mechanical device that cools the air pulled in from a turbo or supercharger
Boost: Measured in pounds per square inch (PSI) and describes how much air is being forced into the engine
Wastegate: Reroutes and releases exhaust gases away from the turbine when peak boost is reached. Prevents more boost from occurring.
Blowoff Valve: Releases air that is 'trapped' when you let off the throttle
Forced Induction: What does it mean?
There are a few ingredients that an engine needs to make power; compression, cold air, fuel, and a spark—forced induction or not. Forced induction refers to when something like a turbocharger or a supercharger, forces more air into your engine than it normally does through its stock intake.
When your turbocharger, for example, sucks more air into your engine, it increases the pressure, temperature, and density of the air, otherwise called boost, which then is fed through a series of piping to the intercooler, and long story short makes more ponies that you can have fun with.
The purpose of forcing more air into your engine is to turn it into more power. When we talk about boost, it’s essentially describing how much air your turbo or supercharger is pulling in from outside, or what PSI (Pounds per square inch).
Depending on your supporting mods, you may be able to run a higher boost or if you’re like some people, you’ll run crazy boost without those supporting mods and may experience some loud booms and pops. No one wants that.
Boosting your engine generally becomes more complicated especially if you start with a naturally aspirated, or non-boosted engine. We can all picture that one guy at car meets whose boosted car has been broken longer than it’s actually seen the road, or whose car is running on crazy boost and could explode at any moment.
Don’t be that guy. If you don’t cut corners, the results are absolutely worth it. And we’re back to those cool boost noises…
Turbochargers are hands down the most common route for going boosted in this generation of car enthusiasts. We even see more turbocharged cars coming from the factory than we do supercharged cars.
The biggest difference between a turbocharger and a supercharger is that a turbo recycles exhaust gases to create boost; not to mention all the extra piping involved with a turbo setup. A turbocharger setup uses four main components: the turbo, a wastegate, an intercooler, and a blowoff valve.
The turbocharger begins by recycling the exhaust gases from your engine to spin its internal turbine, which is connected via a shaft to the compressor wheel. In turn, the compressor wheel pulls in air from outside. The air is then pressurized, which is where boost and turbo lag come into play.
When air is pressurized, it becomes hot. Since your engine prefers cold air which is dense, the hot air will circulate through an intercooler to be cooled before entering the combustion chamber. There are two types of intercoolers, one uses liquid and the other uses air. The most common is an air-to-air intercooler. If you've ever heard, "this is good boosting weather", it's because the cold outside air temperature is better for boost and combustion.
After the air is cooled by the intercooler, it flows through the intake manifold and into the combustion chamber where all the good stuff happens. However, if you let off the throttle before it can pass through the throttle body trapping the air, or boost, the blowoff valve will open releasing that pent up boost. This is where all the cool whistle noises come from.
- Makes cool noises
- **Generally** less expensive (not always)
- More efficient since it recycles exhaust gases
- More universal
- Better gas mileage compared to superchargers
- The dreaded turbo lag
- Uses engine oil which puts more demand on the oil, may need to be replaced more often
- Lots of piping to fabricate
When most people think of superchargers, they immediately think of muscle cars and big V8s. Since these bigger engines start with a larger displacement compared to a little 4-cylinder, they respond to superchargers very well. You can make some massive power by supercharging big V8s in old Camaros or Corvettes.
There are four types of superchargers that are on the market; Roots, Centrifugal, Twin-screw, and Electric. The two positive displacement superchargers out of this list are the Roots and the twin-screw. To keep things simple, we’ll stick with the twin-screw supercharger.
Like I mentioned before, the biggest difference between a turbo and a supercharger is its method of pulling in outside air. A twin-screw supercharger is mounted on top of the intake manifold and uses the crankshaft pulley and a supercharger belt to spin the two 'screws' inside the supercharger.
This compresses the air as it moves through the supercharger. Once the air passes through the throttle body and the two screws within the supercharger, it is forced directly into the intake manifold, unlike the turbo setup that requires a lot of piping.
The two screws inside the supercharger are two separate designs that interlock but don't actually touch. the air becomes compressed inside the supercharger when it passes through the small space between the two screws. Wait, wouldn't the air be hot since it's going directly into the intake?
Unlike the turbo, twin-screw superchargers use an internal intercooler that cools the air before it actually enters the intake. As far as blowoff valves and wastegates go, centrifugal superchargers use an internal bypass valve and use a blowoff valve only when a mass air-flow meter, or MAS, is used.
A huge advantage that almost everyone talks about when discussing going supercharged instead of going turbo is the lag. Superchargers don't experience lag because it isn't waiting for those exhaust gases to spool the turbo.
The supercharger turns as the engine turns since it runs on the crankshaft pulley. However, supercharged engines generally don't run on higher boost levels compared to turbos as a result of this.
- No lag!
- Better throttle response as a result of no lag
- Cools air very well
- Low RPM boost
- No engine oil used
- Generally less efficient since it uses energy from the engine
- More expensive due to the design
What should I boost my car with?
I know you aren't going to like this answer, but it depends. It depends on the platform you're on and what the kind of aftermarket support is out there. If you have a smaller engine and don't mind sourcing the piping fabrication, a turbo might be the better option.
Superchargers are more application-specific. If you have a Camaro, Corvette, or Mustang, for example, supercharging is certainly more common and feasible. We would suggest you hop online and find a group specific to your car and see what others are doing. Also, take a look online to see if there are supercharger or turbocharger kits available that fit your car.
What do you prefer? Superchargers or Turbos? Let us know what you think in the comments below! We'd love to hear from you.