Knowing why when it comes to your diesel pickup is important as you choose parts to enhance its performance, so I wanted to break down why compound turbos (twins) are far superior to single turbos.
- There is an increase in horsepower. With compound turbos, you don’t have to compromise between slow spool up and high end or quick spool up and no top end. A compound turbo has two turbos. Not only, does the smaller one allows it to spool up as quickly as most stock turbos and the large one provides a lot of air for the top end, but the pressure is multiplied between both turbos so a lot more air is available, then with either turbo by themselves. This equalizes the pressure between the exhaust driving pressure and the boost pressure so that the pressure exerted on the top of the piston during an intake stroke is similar to the pressure exerted on the piston when it pushes the exhaust out. This balanced pressure allows for less loss of horsepower because the power to push the exhaust out is recuperated as boost air comes back in as the intake valve opens.
- You engine stays cooler. With compounds, there are excess air molecules in the cylinder. There are enough air molecules to consume fuel and carry out the heat that isn’t involved in combustion. There is also more cool air going to the cylinder because the turbos are each spinning at lower pressure ratio, the air exiting the turbos is cooler than the air from single turbos and there is cooler, denser air entering the cylinder.
- Your turbos last longer. In a compound turbo, each one works less than it would have in a single turbo. Both turn at a lower pressure ratio yet produces higher total boost. This is great for the longevity of your turbos, and engine.
–Diesel Power Source