Increase Turbo Pressure via Wastegate

• Identify the type of fitment on your car.
• Depending on the type of assembly, it is possible or not to adjust the turbo pressure.

With a wastegate turbocharger.
In this configuration, the regulation is done by a valve which diverts the gases by a bypass: it is an all or nothing action and the regulation is done by alternating openings and closings of the channel.
Two versions exist.
* Case 1: the valve is pneumatically controlled by the pressure in the intake manifold. At maximum pressure, an opposing calibrated spring is pressed, controlling the opening of the by-pass. Boosting the turbo pressure is possible with a pressure regulator.
* Case 2: the valve is actuated by an air depression activated by a solenoid valve. The source of depression is the vacuum pump for diesel, and the depression downstream of the throttle valve for gasoline. The solenoid valve is then controlled by the engine management computer. The pressure value is given to the computer by a boost pressure sensor. Increasing the turbo pressure is possible with a pressure accessory, depending on the behavior of the computer after a test.
Good to know: sometimes, the computer detects the increase in pressure and can then adopt, after illumination of the diagnostic warning light, a degraded operation of the engine.

* With a variable geometry turbocharger (VGT):
This type of turbocharger controls the intake pressure by fins controlled in depression by a solenoid valve, itself controlled by the engine management computer.
Good to know: the advantage of this type of turbo is its progressiveness. The increase in pressure is possible on the older generations, just like the previous systems, insofar as the computer does not interfere.
* The very latest generations of vehicles prohibit the increase in turbo pressure (since the Euro V standards), but with a pressure accessory it is possible.
Good to know: the engine management systematically checks the correct deflection of the control capsule by a feedback sensor, which analyzes the position of the turbo regulation control, prohibiting any modification. The only alternative is then an engine reprogramming. It is therefore essential to identify the existing assembly on your car to find out if it is possible to intervene on the turbo pressure. This is why the use of a pressure accessory makes it possible not to disturb anything on the original assembly of the vehicle, and to optimize the turbo as much as possible.

Step 1:
Set up a pressure gauge
It is important to control the increase in pressure, and therefore to know the modified value.
* Take a pressure gauge graduated from 0 to 2.5 bar (for reading accuracy).
* Connect a flexible nylon hose (2 to 2.50 m long) to the intake pressure.
* For direct control by intake pressure (first generations), using a tee, connect to the hose connecting the intake and the "wastegate" on the turbocharger.
* For vacuum controls, the pressure value is taken from the inlet manifold or the air hoses: use an existing connector (pressure sensor or other) or pass a small diameter rigid tube under a hose. look at its interlocking.
Important: take care to respect the tightness of the assembly.
* Route the hose towards the passenger compartment on the passenger side, and pass it through the half-open passenger window.
Important: do not crush the hose when closing the bonnet.
* Connect the pressure gauge to the hose.

2nd step:
Record the maximum road pressure
* For reading, get help from a second person who sits on the passenger side.
Important: For your safety, never perform this operation alone.
* Carry out a road test and record the maximum pressure delivered; it appears with the accelerator pedal fully depressed.
Important: the EGR valve must not be in operation during the pressure reading.
* Consult the technical review of the car and compare the value noted with the manufacturer's value. The average values range between 650 and 1200 millibars (relative pressure).
* Remember: atmospheric pressure is approximately equal to 1000 millibars (1 bar);
* the relative pressure is the additional pressure produced by a system (the turbo for example);
* absolute pressure is the addition of atmospheric pressure and relative pressure. Here, the absolute pressure values of turbo pressure therefore vary from 1,650 to 2,200 millibars).

Step 3:
Adjust the turbo pressure value
Important: the turbocharger and the exhaust gases reach very high temperatures (800°C), there is a significant risk of burns. (Allow the engine to cool before intervening).
* With the vehicle stationary, access the wastegate control rod. This has a thread locked by a lock nut.
* Unlock the lock nut.
* Disconnect the turbo valve rod by removing the clip that secures it.
* Screw according to the case:
1/If the Wastegate pulls the depression valve, the control rod must be extended to delay the depression or its opening.
2/If the Wastegate pushes the depression valve, the control rod must be shortened to delay the depression or its opening.
* This operation has the effect of significantly increasing the pressure which remains unmodifiable by the value attributed to the spring, but which will move the activation of the opening of the depression valve, (manufacturer protection). At the same time, hold the rod on the vacuum capsule side to prevent it from rotating. This operation will allow you to control the opening of the depression valve, just after the maximum thrust of the turbo, and to cause perfect regulation. After this operation, it suffices to place a pressure accessory, which alone can increase turbo pressure management, without intervening in the manufacturer's setting.
Important: screw by 1/2 turn at most,
(The variation in position must remain substantially close to the factory setting).
* Refit the control rod and lock the lock nut, or replace the clips.
* Perform a new test drive:
* the power must be usable;
* acceleration must not cause black smoke.
* Correct the setting if necessary.
* To carry out this operation you need a pressure gauge and a hose to be connected in series on the Wastegate hose.
Important: you must always check the travel of the depression valve after having worked on this rod, at the risk of seeing opaque smoke when accelerating and having made the opening of the depression valve reduced and not total.
Note: if your vehicle is operating normally, it suffices to place a pressure accessory to intervene on the turbo pressure.