For normal driving, the Surbo already makes a difference, and its max power (with the engine working at full throttle) is shown in the Dynamometer Test Results.
The Surbo, which has no moving parts, is made of pointed fins curled to one side, and is fitted with the sharp points towards the throttle. To activate the Surbo, follow steps 1 to 3 below.
1. As the vehicle is accelerated to around 2500 rpm, the air flows straight past the fins, as it is easier to flow straight, since the absolute pressure straight ahead is lower compared to under the pointed fins.
2. For up to one second, the throttle is closed slightly, making a backward air pressure towards the Surbo, and when this back pressure is high enough it makes the air go under the fins towards the pointed ends, and the air is emitted as crossed jets, which match or even raise the back pressure. The cross jets create a vortex within the Surbo to draw air in more strongly. Since there is a momentary high pressure between the Surbo and the engine, the engine's speed is still increasing. The exhaust system is then filled with higher pressure gases and ready to blast. The engine is now set to accelerate much faster than before.
3. The accelerator is pressed again slightly, and the throttle sends the higher pressure air into the engine for quicker acceleration. Since the throttle is still half closed, the region after the Surbo is at a higher pressure than outside air, so the incoming air is forced to go under the fins towards the pointed ends, and the jets and vortex are prolonged throughout the acceleration. For turbocharged vehicles, step 3 may not be necessary as the denser exhaust gases may have already turned the turbocharger on.
The result is that the engine reaches the rpm red line with just 1/2 throttle! This is easily done for manual vehicles as the gears can be held. For automatic vehicles, even in D mode, instead of normally switching gears at 3000 rpm, the engine can reach between 4500 to 6000 rpm with half pressure on the accelerator, depending on the gearbox program.
To extend rpm, steps 2 and 3 can be repeated with small movements on the accelerator, to keep increasing the back pressure towards the Surbo to make it jet harder. It's quite fun to feel the vibration on the accelerator due to increased air flowing through the small throttle opening, and the push in your back, with little accelerator pressure! You can play catch-the-Surbo throughout your drive!
By the above, the Surbo can generate its maximum air pressure, and take over more of the work of the engine. This increases throttle sensitivity, saves fuel and cuts emissions, because only 1/2 throttle is required for the engine to reach its rpm limit. Even for relaxed driving, this method can be applied, whenever there is one second to spare, such as having to follow other vehicles, or when cruising. When cornering, because the accelerator is eased off, the Surbo may be automatically activated and helps the engine power through the bend, and even sharpens the turn-in for front-drive vehicles.
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Above: video of Volvo XC90 T8 with Surbo, sprinting to 130 kph.
Above: video of Volvo XC90 T8 with Surbo, sprinting to 211 kph.
Above: video of Volvo XC90 T8 with Surbo, sprinting to 224 kph.
Less knock (allows lower octane)
