FEOA Forums banner
1 - 10 of 10 Posts

·
Registered
Joined
·
513 Posts
Discussion Starter · #1 ·
I see that most wastegates come with spring set to differnt psi. I understand that this is the amount of boost that the turbo system is limited to.

So... How is boost increased on these systems. Does the Boost controllers available apply extra pressure to the spring to prevent it from opening?
 

·
Registered
Joined
·
73 Posts
The boost pressure is what opens the wastegate, for example: You have a 10 pound spring so when the wastegate senses 10 psi and the wastegate opens.

If you have a boost controller it tricks the wastegate buy resticting the boost to what ever you have it set at, when it reaches that point the boost pressure flows though and then opens the Wastegate. You CANNOT set a boost controller to run less boost then the spring in the wastegate.

IE: 10psi wastegate, you set the Boost controller to 15psi, the boost controler resticts the wastegate from opening until 15psi. It pretty much just pinches the line so that the wastegate doesnt see what boost its actually at.
 

·
Premium Member
Joined
·
8,141 Posts
the spring on a wastegate is not the max boost. that is the lowest boost the waste gate will open at. a boost controller is designed as you state to trick the system. that is why its called a controller. lol ;)

IE: 10psi wastegate, you set the Boost controller to 15psi, the boost controler resticts the wastegate from opening until 15psi. It pretty much just pinches the line so that the wastegate doesnt see what boost its actually at.
like he said its a really cool reversed funnel basically. it sees 15psi on one side but shows 10 on the other if adjusted correctally. its a spring and seal/baring that only will allow the adjusted psi by.

NEUMAN
 

·
Registered
Joined
·
465 Posts
marclar said:
first of all theres no spring.. its a diaphragm with a rod attached to it. some have threaded rods and some dont....
remind me what u ran in the 1/4 again?

 

·
Registered
Joined
·
2,709 Posts
All wastegates that I have seen on the market, both internal and external, work on spring-diaphragm.

When you have a pressure of X psi, the pressure exerts a force on the diaphragm. This diaphragm is opposed by a spring of spring constant k. The integral of the pressure exeerted on the diaphragm is equal to a total force, which, at a certain predefined pressure, will equal the force of the spring. The downside of this design is that a spring has a linear constant, so as the pressure on the diaphragm increases, the force opposing the motion also increases linearly. In an ideal situation, a wastegate would work on a digital system, being fully closed or fully open. In reality, this isn't so.

The diaphram can be opposed by a spring either internally (inside the "head" of the physical device. Or it can also be opposed by a spring on the shutter of the wastegate. In addition, it could also theoretically be opposed by the stiffness of the diaphragm itself, but this would probably be unreliable.

External wastegates work the same way.

If you want a really good wastegate, you should hook up a pressure transducer to your static "pitot" pressure, then wire a circuit to a solenoid actuated wastegate. This would likely spool significantly faster and provide much better response over a traditional wastegate. I wouldn't be at all suprised if a system like this already exists on the consumer market, and something very similar is most likely used in rally and racing applications already.
 
1 - 10 of 10 Posts
Top