Eboost Street connection
05-30-2013, 07:01 PM
#21
Ferocity, you are talking about the duty cycle, he asked about sensitivity.
If you see your boost spike you want to lower the sensitivity some, if it comes up too slow you can raise it some. I think mine is set at 23.
0 duty cycle should be just gate pressure while 100 will be gate pressure + boost pressure on top if you are using the 2 port method. For just the single lower port, 0 will again be less than gate pressure and 100 will gate pressure.
If you see your boost spike you want to lower the sensitivity some, if it comes up too slow you can raise it some. I think mine is set at 23.
0 duty cycle should be just gate pressure while 100 will be gate pressure + boost pressure on top if you are using the 2 port method. For just the single lower port, 0 will again be less than gate pressure and 100 will gate pressure.
05-30-2013, 09:06 PM
#22
1 port method on max should be the same as just spring pressure.
Now that I look at the diagrams again, it seems that the 1 and 2 ports methods would have the same boost at the lowest and highest settings. With the two port method on max, the boost pressure above and below the gate is the same and would cancel eachother out, leaving just spring pressure. Or is the solenoid somehow acting as a check valve to the top port, letting pressure in but not letting it out? I've gone and confused myself again!
Now that I look at the diagrams again, it seems that the 1 and 2 ports methods would have the same boost at the lowest and highest settings. With the two port method on max, the boost pressure above and below the gate is the same and would cancel eachother out, leaving just spring pressure. Or is the solenoid somehow acting as a check valve to the top port, letting pressure in but not letting it out? I've gone and confused myself again!
05-30-2013, 09:36 PM
#23
With the 2 port method the solenoid pressurizes the top port which helps keep the wastegate shut (i.e. more boost). This cannot be achieved with only using the bottom port of the gate where more pressure there helps to open the wastegate.
I'm just trying to figure out if I'm seeing 7 psi now with the wastegate referenced to the manifold if this will be the same when I hook up the Eboost with the duty cycle set to 0
I'm just trying to figure out if I'm seeing 7 psi now with the wastegate referenced to the manifold if this will be the same when I hook up the Eboost with the duty cycle set to 0
05-30-2013, 10:02 PM
#24
Wiser, not necessarily...the total boost possible is lower with the 1 port, so there is less of a risk you could say.
If you look at the flow diagram, the solenoid basically switches between the source port and 2 output ports. The amount of time spent on the normally closed port compared to the normally open one is called the duty cycle. So if you have a duty cycle of 75, that means the normally closed one is open on average over a given time period, 3 times longer than the normally open one. That may be a little confusing, but basically the solenoid is switching back and forth really quickly, so if you imagine 0 being open and _ being closed, from the prospective of the normally closed port, it would see this set on 75: _000_000_000_000 etc., whereas 25 would be ___0___0___0 etc.
This guy does a better job than me: How does a electronic boost controller work
So...that was probably confusing, but if we then think about the extreme cases of 0 and 100 using the different methods...
I am using this a reference: http://www.turbosmartusa.com/wp-cont...psi_MAY_12.pdf
Lets assume gate pressure is set to 0psi to make this easy. It looks like the ports on the left is port 2, center is 3, and right is 1. Port 2 is normally connected to 3, and switches to 1. (see pic of the solenoid: http://img801.imageshack.us/img801/4915/p7032468.jpg)
1 port method (page 7, example 1):
At 0 the normally closed port (port 1) will never get pressure so all the pressure from port 3 goes to port 2. Looking at the diagram, this means you have boost pressure + exhaust pressure acting against spring pressure only. This will result in the lowest boost possible
At 100, port 2 is switched to port 1 and port 3 doesnt do anything. So essentially the controller is acting like its not even there and the lower port is unreferenced. This usually results in double the spring pressure since now it is just exhaust acting against spring.
So we can conclude every value between 0 and 100 results in a boost pressure between the lowest possible and a max of normal unreferenced wastegate spring pressure.
There are two 2-port methods
Using the first one (page 8 example 2):
At 0 you have the t line helping open the gate and the solenoid stays with ports 2 and 3 connected so you will have boost + exhaust acting against the spring only with the top essentially being unhooked. This will result in the same thing as 0 using the 1 port method; the lowest boost possible since you have boost pressure + exhaust acting against spring only.
At 100 you will again have the boost pressure + exhaust on bottom, but you will have the spring pressure and now the boost pressure on top, so the boost pressures will cancel each other out and you now have exhaust pressure acting against spring pressure. So how is this different than just using an unreferenced wastegate? Because this is intended for setups with high back pressure, so the total pressure difference on the gate, which is what really matters in the end, will be more even. (20+6/20+10)=0.867 whereas (6/10)=0.6 (I assumed 20psi of boost, 6lb spring, and 10lb backpressure) As this number gets closer to 1 the the boost is balancing out with the backpressure so it doesnt act like a high backpressure system any more.
Using the second 2 port method (page 10 example 1):
At 0 you have boost + exhaust acting against spring only, resulting in somewhat low boost.
At 100 you have boost + spring acting against exhaust. This will result in the highest boost possible your turbo can make and should not be taken lightly. This is essentially the same thing as running a line from the compressor to the top port of the wastegate and can lead to overspeeding the turbo and overboosting.
This configuration will result in the widest range of boost possible.
Hope this helps some...
If you look at the flow diagram, the solenoid basically switches between the source port and 2 output ports. The amount of time spent on the normally closed port compared to the normally open one is called the duty cycle. So if you have a duty cycle of 75, that means the normally closed one is open on average over a given time period, 3 times longer than the normally open one. That may be a little confusing, but basically the solenoid is switching back and forth really quickly, so if you imagine 0 being open and _ being closed, from the prospective of the normally closed port, it would see this set on 75: _000_000_000_000 etc., whereas 25 would be ___0___0___0 etc.
This guy does a better job than me: How does a electronic boost controller work
So...that was probably confusing, but if we then think about the extreme cases of 0 and 100 using the different methods...
I am using this a reference: http://www.turbosmartusa.com/wp-cont...psi_MAY_12.pdf
Lets assume gate pressure is set to 0psi to make this easy. It looks like the ports on the left is port 2, center is 3, and right is 1. Port 2 is normally connected to 3, and switches to 1. (see pic of the solenoid: http://img801.imageshack.us/img801/4915/p7032468.jpg)
1 port method (page 7, example 1):
At 0 the normally closed port (port 1) will never get pressure so all the pressure from port 3 goes to port 2. Looking at the diagram, this means you have boost pressure + exhaust pressure acting against spring pressure only. This will result in the lowest boost possible
At 100, port 2 is switched to port 1 and port 3 doesnt do anything. So essentially the controller is acting like its not even there and the lower port is unreferenced. This usually results in double the spring pressure since now it is just exhaust acting against spring.
So we can conclude every value between 0 and 100 results in a boost pressure between the lowest possible and a max of normal unreferenced wastegate spring pressure.
There are two 2-port methods
Using the first one (page 8 example 2):
At 0 you have the t line helping open the gate and the solenoid stays with ports 2 and 3 connected so you will have boost + exhaust acting against the spring only with the top essentially being unhooked. This will result in the same thing as 0 using the 1 port method; the lowest boost possible since you have boost pressure + exhaust acting against spring only.
At 100 you will again have the boost pressure + exhaust on bottom, but you will have the spring pressure and now the boost pressure on top, so the boost pressures will cancel each other out and you now have exhaust pressure acting against spring pressure. So how is this different than just using an unreferenced wastegate? Because this is intended for setups with high back pressure, so the total pressure difference on the gate, which is what really matters in the end, will be more even. (20+6/20+10)=0.867 whereas (6/10)=0.6 (I assumed 20psi of boost, 6lb spring, and 10lb backpressure) As this number gets closer to 1 the the boost is balancing out with the backpressure so it doesnt act like a high backpressure system any more.
Using the second 2 port method (page 10 example 1):
At 0 you have boost + exhaust acting against spring only, resulting in somewhat low boost.
At 100 you have boost + spring acting against exhaust. This will result in the highest boost possible your turbo can make and should not be taken lightly. This is essentially the same thing as running a line from the compressor to the top port of the wastegate and can lead to overspeeding the turbo and overboosting.
This configuration will result in the widest range of boost possible.
Hope this helps some...
05-30-2013, 10:18 PM
#25
Nice post.
If I can double my boost with the 1 port method I will try that. Turbosmart recommends starting with the 1 port method and going from there. My only concern is having to re-do things and not being able to get 14-15 psi with the 1 port method. Although not failproof, I'm not too concerned with overboosting with the 2 port method because of the overboost function the unit has.
If I can double my boost with the 1 port method I will try that. Turbosmart recommends starting with the 1 port method and going from there. My only concern is having to re-do things and not being able to get 14-15 psi with the 1 port method. Although not failproof, I'm not too concerned with overboosting with the 2 port method because of the overboost function the unit has.
05-31-2013, 12:15 AM
#26
At 100 you will again have the boost pressure + exhaust on bottom, but you will have the spring pressure and now the boost pressure on top, so the boost pressures will cancel each other out and you now have exhaust pressure acting against spring pressure. So how is this different than just using an unreferenced wastegate? Because this is intended for setups with high back pressure, so the total pressure difference on the gate, which is what really matters in the end, will be more even. (20+6/20+10)=0.867 whereas (6/10)=0.6 (I assumed 20psi of boost, 6lb spring, and 10lb backpressure) As this number gets closer to 1 the the boost is balancing out with the backpressure so it doesnt act like a high backpressure system any more.
If I can double my boost with the 1 port method I will try that. Turbosmart recommends starting with the 1 port method and going from there. My only concern is having to re-do things and not being able to get 14-15 psi with the 1 port method. Although not failproof, I'm not too concerned with overboosting with the 2 port method because of the overboost function the unit has.
05-31-2013, 12:31 AM
#27
My numbers probably sucked on that example...a better one would be 15psi of boost, 8lb spring and 30psi of backpressure
controller: [(15+8)/(15+30)] = 0.511
gate only: (8/30) = 0.2667
I mentioned as this gets close to 1 it balances out...interestingly, in a pure race setup on a gas engine you may get to a 1:1 ratio of boost to backpressure with a huge turbo and small engine, and then the engine behaves, thermodynamically anyway, just like a huge NA engine.
controller: [(15+8)/(15+30)] = 0.511
gate only: (8/30) = 0.2667
I mentioned as this gets close to 1 it balances out...interestingly, in a pure race setup on a gas engine you may get to a 1:1 ratio of boost to backpressure with a huge turbo and small engine, and then the engine behaves, thermodynamically anyway, just like a huge NA engine.
06-10-2013, 04:31 PM
#28
Ok....I set mine up and I can only get 12psi no matter what I've done.
Have it hooked up like this.
page 10 example 1
Two port, single solenoid, single turbo connection method 2
port 1 of solenoid to top port of wastegate
port 2 of solenoid to pressure source on turbo housing
port 3 of solenoid to bottom port of wastegate
I've try setting sp1 to as much as 99
gp1 is 15
sn1 is left at 20
So what's the deal??
Have it hooked up like this.
page 10 example 1
Two port, single solenoid, single turbo connection method 2
port 1 of solenoid to top port of wastegate
port 2 of solenoid to pressure source on turbo housing
port 3 of solenoid to bottom port of wastegate
I've try setting sp1 to as much as 99
gp1 is 15
sn1 is left at 20
So what's the deal??
06-10-2013, 04:35 PM
#29
Ok....I set mine up and I can only get 12psi no matter what I've done.
Have it hooked up like this.
page 10 example 1
Two port, single solenoid, single turbo connection method 2
port 1 of solenoid to top port of wastegate
port 2 of solenoid to pressure source on turbo housing
port 3 of solenoid to bottom port of wastegate
I've try setting sp1 to as much as 99
gp1 is 15
sn1 is left at 20
So what's the deal??
Have it hooked up like this.
page 10 example 1
Two port, single solenoid, single turbo connection method 2
port 1 of solenoid to top port of wastegate
port 2 of solenoid to pressure source on turbo housing
port 3 of solenoid to bottom port of wastegate
I've try setting sp1 to as much as 99
gp1 is 15
sn1 is left at 20
So what's the deal??