how is a wastegate controlled? a solenoid opens and closes it right? but if you desire a certain intake pressure how do you know how much exhaust to feed the turbine? does the boost controller monitor intake pressure and then change the wastegate setting to get the desired boost level?

 

im not positive on the external wastegates but the internal wastegates are controlled by an actuator. The actuator senses boost pressure once the boost starts to build the actuator opens the wastegate to let the exhaust bleed off.

The boost controller interupts the signal to the actuator. Essentially tricking it into staying closed longer and allowing the boost to go higher.

For controlling the boost most of the controllers I have used you will need a boost gauge. (manual boost controller) You start with the controller wide open so it would boost at the factory spec (not interfer with signal to actuator). Then you start to close it a little at a time after each full boost run. you keep closing it till you reach the level that you were trying to get.

I had a electronic apexi boost controller before and it would allow me to interupt the signal in percentages which was essentially the same as the manual one except I got to puch buttons instead of turning a ****.

Also I have heard that some actuator arms have a little adjustability in them. That will let you adjust the boost a little.

hope this helps
Sean

 

yea it did help, thanks sean. so you dont actually pick a certain psi, you sort of tune the boost contoller until you get it to what you want? i bet the external wastegate is pretty much the same. im also wondering what are the advantages/disadvantages of the external vs internal wastegates.

 

With manual boost controlers it is guess and check. With electronic ones you can set boos to a certain psi, and when the boost reaches that psi (or just before it) the selenoid directs the pressure to the wastegate actuator.

What are the advantages of external?

1. Open venting is loud and sounds mean as hell, not to mention a little extra hp from open exhaust
2. Any turbo that requires an external wastege will not have performance hindering abstructions based around an internal wastegate. The exhaust will not hit the wall of a closed internal wastegate because there is not one, all exhaust is directed smoothly through the turbine.
3. they look cool and high performance...? (any list must have at least 3, so that will be my third)

-Marques

 

i thought the idea was to have both a bov(external weastegate) and an internal one, the ionternal to control the boost while driving like described above and the external to stop damage to the turbo when the butterflies close. then again i am fairly new to cars and am probably completely wrong

 

BOV and a Wastegate are two different beasts, with two different purposes. Do a search on BOV's I did a little write up a time back explaining.

Sean

or you can go here i did the search

https://www.rx7club.com/forum/showth...blow+off+valve

 

ahh alright, i just thought i remembered reading somewhere ages ago when i didnt even know how a bov worked that another name for it was external wastegate