Everyone has heard of this engine component of the car called a turbocharger but surely very few of you know how it works or what additional accessories it has for it to function properly and at maximum capacity. In this article, we will talk about a very important component of the turbo, specifically about the wastegate valve.
Some of you may have heard of this turbocharger component, but for those who do not know what it is or what does it do, they will learn more after reading this article.
At the moment, after a study, I found out that over 75% of the cars sold are equipped with turbocharged engines, in most cases with the help of a mechanical turbo. The turbocharger, or simply the turbo, has a very simple way of operation, consisting of the fact that the exhaust gases are directed by the exhaust gallery in the turbo.
The gases turn the turbo blades to over 250,000 rpm, in turn, the turbo spins the blades of a compressor through an axis. These blades, which we are talking about, are like a propeller but specially designed to absorb the air from the atmosphere and to put it with pressure into the engine intake system.
But if these blades reach over 250,000 rpm, in “full boost”, you will realize that they would not last too long, the wear being high enough at this speed and in addition the engine would not withstand such continuous stress. . So the big car manufacturers thought they had to limit the speed of the turbo to a certain extent, it couldn’t always go to the maximum.
What is the turbo wastegate valve?
The only solution to redirect the exhaust gases so as not to accelerate the turbo blades was the invention of this piece called the wastegate valve. This valve practically evacuates the useless gases to keep the optimum pressure in the turbo. Normally the name “wastegate” means “escape gate”.
This wastegate can be found on any turbo car, but without this part, the turbocharger would spin at too much speed for far too long, which would simply result in self-destruction, but at the same time would create huge pressure on which the engine may not support and will cause it to fail.
If the exhaust gas flow is too high, then this wastegate valve will open and some of the gas will no longer pass through the turbo so that the pressure is kept at optimum parameters. In the factory stock cars, these gases are also directed to the exhaust, while in some modified cars, the gases are evacuated directly into the atmosphere, for higher performances.
Types of wastegate valves
There are 2 types of wastegate valves, indoor and outdoor. The inner ones are directly in the turbo housing and the others are on the outside. This valve is controlled in turn by a mechanical, electronic or vacuum actuator, which is responsible for opening and closing the wastegate valve at the right time.
Symptoms and faults of a bad wastegate valve?
Well, the most common fault would be the one in which the valve is blocked due to calamine. If the valve locks in the closed position, the car will run much better (thanks to the increased intake pressure) but at the same time damage will occur because this increased pressure will overload the engine, the most affected being the intake valves.
There are still cases where the vacuum hoses fail and the wastegate valve is no longer controlled by the actuator. In general, this valve does not break so easily but if we do any operation on the turbo, then it would be best to check the wastegate to not have any surprises. The vacuum actuator sometimes breaks (more precisely the inside membrane breaks and becomes unable to close / open the wastegate).
Also, this valve has an adjustment (a thread) and can be adjusted when opening or closing. But I recommend that you do not use that setting if you do not have the necessary knowledge, I damaged an engine after I used that setting. The car was running much better with a slight increase in turbo performance, but it didn’t last much, the turbo gave up after 5000 km (3000 miles), I changed the turbo and rebuilt the engine, which could not withstand the stress and failed as well, especially since the car in this example was a van that was more loaded with cargo, so we are talking about much higher temperatures.
At the moment most of the actuators on the market are electronic, they have the advantage that they can be very fine-tuned, ECU reads hundreds of real-time data, for example, pressures, temperatures, acceleration position, etc. and adjusts the wastegate position in millimeters so that to achieve maximum performance.
But the great advantage of the electric actuator is that it is electric and thanks to the extreme temperature (the turbine reaches 800 degrees Celsius or 1472 F) and the vibrations, the electrical part can fail. The prices for the repair of an electric actuator are around $200 – $300. So are the prices for the other types of actuators.
I talked a bit about actuators because the wastegate is dictated by the actuator, so the two components must work perfectly. Remember, this piece is very important so your best option is to opt for a professional mechanic when you want to do anything on your turbo.
Even if only when you clean or refurbish it, always call a specialist. The adjustment of the actuator and the wastegate must be done with the help of special devices, it is not to play with them, as I said above, I even damaged an engine due to a stupid adjustment, made “by ear”.