Actuator / Wastegate
Location: On the turbo
What is an actuator / wastegate, and what does it do?
As mentioned in the "Turbo Section" with different parts having different names, this "wastegate" being referred to is the Swing Valve Controller and not the blow off valve. To avoid further confusion I shall refer to it as the Actuator.
There are two types of actuator, adjustable, and fixed type.
They work with air pressure from the intercooler (from the Charging Pressure Control Solenoid), and consist of a spring and diaphram inside the "dome", which pushes the rod, that has the wastegate flap attached ( in all the Swing Valve Controller).
How it works - when a given amount of pressure (1 bar for example) has built up inside the turbo, it needs to be let out, when adjusted correctly, the actuator controls the pressure release, and can give a lot more power to the engine (when holding in the pressure). Hence the term "raising boost pressure).
The actuator also works in conjunction with the solenoid, the solenoid controls the amount of pressure in the actuator, which opens and closes the wastegate, allowing excess pressure built up, to be expelled into the exhaust system. At the same account, it also allows boost to build up in order to gain more power.
O.E.M. fitted Actuator:
Nissan have fitted a non adjustable Actuator as standard to the R33 GTST, therefore the boost level is set to its limit and cannot be altered or adjusted to increase or decrease boost levels, without some sort of boost controller, or replacing the OEM Actuator for an alternative.
Available Options:
Electronic Boost Controller, and Dawes type adjustable Actuator.
Most people prefer Electronic Boost Control as its easier to adjust in most cases, also it can be done "in car, on the road", which makes it the safer option as you can physically see what levels of boost you are running, set warnings and decrease levels if a predetermined level is reached.
The E.B.C is connected into the solenoid, more often than not a new solenoid is part of the package, and then adjustment is made starting from a low boost pressure.
With the Dawes system, adjustment is done manually in the engine bay, and therefore requires a lot more time involved for getting the correct setting, which isnt always guaranteed without the right equipment (for testing pressure)
The problems that it can cause when not set up correctly are:
- Over Boosting - usually caused by the swing gate not opening to allow exhaust turbine wheel to slow down. This can cause detonation and further damage, such as throwing the rods through the block or blown head gasket.
- Under Boost - when the turbo has the wastegate open and therefore cannot build up enough pressure to run the engine under turbo use (it may idle a bit rough, or maybe naturally).
These can be overcome by fine tuning, unless of course there are problems further down the line (ie damaged turbo or engine / components).
The damage can be tremendous on overboosting if not tendered to immediately, as it can damage pistons, connector rods, crankshafts.
If your upgrading the actuator as a Stage 1 Modification, dont get crazy with the amount of boost you set it too, just do a little at a time. I will add "Advised Boost Pressures" as soon as I can to see what can be run at a safe level. (as i havent done this, I havent looked deep into it as yet).
More will follow so please stay tuned.  |
