I'm afraid that I won't hold boost to redline that way.
I actually bought the boost box because I thought that it would direct pressure to the top to shut the gate too... Didn't someone post a pic like that?
Yes, you could hook it up this way as well:
But, if you look closely, it applies boost to the top of the gate and the bottom of the gate as well, which effectively cancels out the pressure up and down. It is the same as applying nothing to both sides, which is what our vacuum setup does.
You can try both ways if you want. We haven't had much luck with the vacuum routing shown above.
You should be able to hold boost to red-line because the controller will adjust duty cycle as needed to keep the boost all the way to redline.
Now, for people that are trying to make a real ton of boost (much more than 23 psi), then you need to supply pressure to the top of the gate and take it away from the bottom. We are working on that setup, but it will require a 4 port solenoid or two solenoids wire in parallel.
We can talk about that setup, if you find you need it.
Try the setup we have drawn up first. I am using that now on S3 and holding 21 psi to redline with no problem. Let's see how it goes. If you need more, we'll try that other vacuum setup.
"Now, for people that are trying to make a real ton of boost (much more than 23 psi), then you need to supply pressure to the top of the gate and take it away from the bottom. We are working on that setup, but it will require a 4 port solenoid or two solenoids wire in parallel."
Question 1:
What about an internal gate with a traditional WGA setup over 23psi...............say 26psi. Single solenoid is fine, correct?
Question 2:
With my current set-up the boost is being controlled with a Hallman MBC. I have a MAC valve in between the turbo and the MBC. My water injection system has a failsafe function that's wired into the MAC valve so that on fault detection it reverts boost control to strictly WGA spring pressure via controlling the mac valve.
When I get your controller can it be wired up into this MAC valve while still retaining the wiring to the W/A system for over ride control on fault detection..........I want to have your controller, use the exiting MAC valve and not have your controller go nuts because there's another device on the same circuit?
Question 3:
For great results while running 26 psi using your controller is there a recommended WGA spring pressure to not go below? Meaning, if I want to have max 26psi should I not look to be using a WGA with a spring pressure lower the XXpsi?
If I am understanding things correctly a lower WGA spring pressure allows to have a wider operating range = min low boost is WGA spring pressure and this is good for boost by gear for traction.........very low boost in low gears to gain traction. But is steady boost control difficult when there's a wide range between the spring pressure and what the controller is trying to maintain via user set parameters as set in the software.
1. I don't exactly know where the limit is. That's something we'll have to explore. What is your boost pressure now when you take control away from the MBC? And what is your max boost now? I would assume that whatever you are doing now with the MBC, you could do at least that when you switch to the EBC. Beyond that, it will require testing.
2. Definitely! That sounds like a great setup. How do you have the MAC valve wired up? Does your W/I system provide power or ground? If your W/I system kills power, then I would say that you should have it kill power to the Boost Box. If it kills ground, then you can have it kill ground to the solenoid.
3. Don't know that one either. That you may need to find from experimenting. I believe that the 4-port solenoid setup that we are working on will improve the situation, allowing a much lighter spring to control higher boost. But, we'll have to test it some. And it will only be for external gate cars since it needs a 2-port gate.
F&F Stage III 47lb turbo
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AGP WGA,
Rolling thunder Race head
Snow Performance Stage II Meth/inj
11.40@125mph 26psi and no boost leak New times with new race head coming soon
The boost to bottom and top is NOT the same as just the bottom.
They might equal each other out, yes.
BUT, 23 psi on the top is actually 37 (plus atmosphere!!!)
So just the bottom is 14 vs 37, where top and bottom is 37 vs 37.
1. I don't exactly know where the limit is. That's something we'll have to explore. What is your boost pressure now when you take control away from the MBC? And what is your max boost now? I would assume that whatever you are doing now with the MBC, you could do at least that when you switch to the EBC. Beyond that, it will require testing.
2. Definitely! That sounds like a great setup. How do you have the MAC valve wired up? Does your W/I system provide power or ground? If your W/I system kills power, then I would say that you should have it kill power to the Boost Box. If it kills ground, then you can have it kill ground to the solenoid.
3. Don't know that one either. That you may need to find from experimenting. I believe that the 4-port solenoid setup that we are working on will improve the situation, allowing a much lighter spring to control higher boost. But, we'll have to test it some. And it will only be for external gate cars since it needs a 2-port gate.
1)
18psi spring and 24psi with the MBC. There's another 2-3psi to add but I'm not going to do it before going back to the tuner for more tuning.
2)
It energizes the solenoid with 12V. If there's a W/A fault detection then there's 0V to the solenoid.
Heres a diagram of the MBC & MAC valve
Based on what you said I'll have the W/A system set up to supply power to your controller.
If you controller looses power the solenoid looses instantaneously looses power, correct. Are there any delays between when you're controller would loose power and hence the solenoid loses power? I would like the action on fault to be as fast as possible.
3)
Sounds reasonable.
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Being able to have a 10-12psi spring in the WGA but yet be able to have very high boost without being erratic would be absolutely fantastic.
Boost by gear, a couple of boost maps and easy integration with my W/A system make this very desirable. Will be ordering before the end of the weekend.
1)
18psi spring and 24psi with the MBC. There's another 2-3psi to add but I'm not going to do it before going back to the tuner for more tuning.
2)
It energizes the solenoid with 12V. If there's a W/A fault detection then there's 0V to the solenoid.
Heres a diagram of the MBC & MAC valve
Based on what you said I'll have the W/A system set up to supply power to your controller.
If you controller looses power the solenoid looses instantaneously looses power, correct. Are there any delays between when you're controller would loose power and hence the solenoid loses power? I would like the action on fault to be as fast as possible.
3)
Sounds reasonable.
________________________
Being able to have a 10-12psi spring in the WGA but yet be able to have very high boost without being erratic would be absolutely fantastic.
Boost by gear, a couple of boost maps and easy integration with my W/A system make this very desirable. Will be ordering before the end of the weekend.
Yeah, your setup would be easy. Just unplug the MBC and open that port to atmosphere. Then wire your red wire through the Boost Box. Red to REd, black of the pair to the solenoid red.
There would be no delay from when the power was cut on the Boost Box and when the solenoid was shut down. We have very little energy storage on board. Essentially none. It would be less than a millisecond.
Cool. We'll have to see about the spring and max boost. I know there are limits to how much boost you can make with a light spring, but I don't know what exactly they are.
OK, looked around.
Where can I find a stock solenoid + plug with wires???
All I can find are MAC 35s for 50 bucks and "AEM" badged MACs for 90 bucks
The plug for the stock solenoid isn't available. You'd have to use the one from your car's wiring harness. You can get the solenoid from Jimmy at S&P for cheap.
Assuming that AEM talked to MAC and did the right thing, then their re-badged solenoids are not the same as the standard MAC solenoids you are seeing. We talked to MAC as well and there are important differences that raise the cost. We looked into making a kit and ended up at pretty much the same price as AEM, once you add in all the fittings, filter, wiring harness and some quality hose.
The boost to bottom and top is NOT the same as just the bottom.
They might equal each other out, yes.
BUT, 23 psi on the top is actually 37 (plus atmosphere!!!)
So just the bottom is 14 vs 37, where top and bottom is 37 vs 37.
Get my point?
No, actually... I'm confused.
23 psi on the top + spring pressure - 23 psi on the bottom = spring pressure
0 psi on the top + spring pressure - 0 psi on the bottom = spring pressure
I'll try again.
Forget boost for a second and think MAP.
When you run 10 psi of "boost" your MAP reads somewhat around 24 psi, because of the baro pressure.
Soooooo...
Running just the lower port at 10 psi of boost means:
24 (14 + 10) vs. 14 (24 on the lower port from the turbo, 14 on the not hooked up upper port due to baro)
Running BOTH ports will be:
24 vs 24
So 10 psi more that hold the gate shut.
Am i wrong?
//edit:
I'll try it simpler:
The top port vented to atmosphere is never 0.
It's always baro. Which is around 14 psi for most folks.
So as soon as you hit "boost" above 0 on a boost gauge, you are over the current barometric pressure.
Therefore, as soon as you apply boost to the top port it's gonna do more than no boost.
I think what you are missing is that the bottom port only sees boost when the solenoid is open, which is at low duty cycle.
For example, if you hold the solenoid completely off (0% duty cycle), then the boost source is directly connected to the bottom of the gate. The wastegate will open when the turbo produces enough pressure on the bottom of the gate to overcome the spring pressure on the top of the gate. In your example, that would make 10 psi, if you have a a 10 psi spring. So, in absolute pressure terms, you have:
24 psi on the bottom of the gate = 10 psi of spring pressure + 14 psi of atmospheric pressure on the top of the gate
Now, if you hold the solenoid completely on (100%), the bottom of the gate is connected to atmospheric pressure. So, you end up with:
14 psi of atm pressure on the bottom < 10 psi of spring + 14 psi of atm on top
So, the gate stays closed until the pressure in the exhaust is enough to force open the gate. But, that doesn't happen at 10 psi because there is an area multiplication factor in the wastegate actuator design. For example, lets assume a 4:1 ratio of surface area. In this hypothetical gate, let's assume that means there are 4 sq inches of surface area on the diaphragm in the actuator and 1 sq in of valve in the exhaust. That means the "10 lb spring" is actually a 40 lb spring. That's because 10 psi of boost on the 4 sq in surface produces 40 lbs of force.
Now, if you have equal pressure on the top and bottom of the gate, you are relying on only the spring to keep it closed. But, because of the area multiplication, that spring can do a pretty good job on its own. Now, that 40 lb spring will require 40 psi on the exhaust side to force the spring open.
The same situation occurs if you have the plumbing setup to apply pressure to both sides of the gate. You have say 20 psi pushing the gate up from the bottom with 80 pounds of force and 20 psi pushing the gate down from the top side with 80 pounds of force. The end result is that you are left with the same 40 lbs of spring force to keep the gate closed.
The only way you can do better in this example is to provide boost to the top side of the gate AND take it away from the bottom side of the gate. Then you can have 20 psi of boost creating 80 pounds of down force plus the 40 pounds of down force in the spring. But, the standard vacuum routing that supplies boost to the top side won't do that, because it also supplies boost to the bottom side. To do this setup requires two valves or a 4-port valve.
Anyway, my numbers in the above situation are all made up. I don't know how many sq in the typical ext gate has or the area multiplication factor. That might be in the specifications for the gate, though... But, it doesn't really change the thought experiment...
Let's take the S3 WGA for example. Weak spring, normally will run 21psi max on it's own & drops boost quickly towards redline. AGP WGA can run 24psi all day long & hold like 22-23 at redline. Would be interesting to see if the boost box & solinoid can use the S3 WGA & still be able to hold 23 at redline while being able to use the 8lb spring in S3 in first gear. Hmmmmm
__________________
11.9@117 so far.
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