As we fit the Surbo to pressurize an engine, we have to ensure that there are no openings between the Surbo and the engine. The requirement is that all the air must pass through the Surbo. This forces us to tighten all the vacuum connections, and the result is a perfect vacuum in the intake manifold. A perfect vacuum not only enhances air flow, it ensures the fuel pressure regulator, which is connected to a vacuum tube, is properly controlled. If that tube is loosely connected, the regulator gets a higher absolute pressure signal, and allows more fuel pressure to reach the injectors, and this can cause high fuel consumption.
The usual places where gaps or breaks can occur are the vacuum tubes, or some other air connection such as that to a vacuum or boost gauge with a bad joint that can cause a vacuum leak. Loose vacuum tubes can be tightened with a small cable tie and sealant applied where it is tied. Bigger tubes can be tightened with metal clips. The lower engine oil breather that is connected from the manifold to the oil chamber can also be loose for some cars, as the connection to the oil chamber can be a push-in type. The way to tighten this is to pull the connection out, put some tape around it, push it back tightly into its hole and apply sealant.
Loose connections include the upper engine oil breather hose, an improperly-designed or badly-fitted air pipe after the air filter, absent clips, and a loose oil dipstick. Often, a less-than-accurate sports-type replica of the filter element may have a poor seal and air can come in through the sides, instead of coming in by the wire mesh in the centre, leading to a drop in air velocity through the air filter.
A very sensitive throttle results from our sealing along the manifold vacuum region and the air channels right up to the air filter, and since the Surbo is also able to press more air into the engine, there are immediate gains in torque and acceleration. Typically, the engine will be able to rev to red line on the rpm meter with just 1/2 throttle, indicating a real improvement in the passage of air, and proof that the vacuum capability of the engine has improved. Also, typical 1.6 litre cars have achieved an extra 30 kph in top speed with the Surbo, largely because the throttle never has to be floored due to the enhanced vacuum. We hope that you can read more about the Surbo and our vacuum-improving installation, and see how the Surbo can benefit your vehicle.