ALL BOOST CONTROL setups EXPLAINED - Boost School #3

What about the engine bosses? Welcome to another episode of Boost School, the YouTube equivalent of a college course on forced induction, made possible by the glorious performance electronics of an e m. In today's episode we're talking about something that's probably just as important as impulse itself and that something is

control

because impulse without

control

is like almost anything else without control, it sucks and in today's episode we're going to explore all the different

boost

control settings, starting from the simplest and most basic to the most complex. most performance oriented

setups

out there so without further ado let's get started and of course we'll start with level one so the simplest and most basic setup consists of your wastegate and your wastegate actuator. discharge, that's it, it is completely mechanical with no electronic components and works like This, the wastegate actuator has an arm that is directly connected to the wastegate.

Inside the wastegate actuator is a spring and a diaphragm. The spring senses the

boost

pressure all the time because it is connected to the compressor side of the turbo through this hose, so any boost pressure is generated. by the turbo is exerted on the spring and the spring in this particular actuator is an 11 psi spring, which means that the wastegate will open fully when the turbo generates 11 psi of boost pressure, so as You can see, unfortunately it's a really simple setup. Its only advantage is simple and getting your turbo to run quickly with a setup like this is almost impossible and the reason is that the wastegate actuator spring is exposed to boost pressure constantly and although the wastegate will open fully at 11 psi, it will actually start. open at boost pressures well below that, now this is bad and you don't want the wastegate to open before reaching the target boost pressure because once the wastegate opens it will divert the exhaust gases away of the turbine wheel, which will cause your turbo to spool more slowly.

The downside to the system is that it's dumb, it only references boost pressure, it has no idea about intake air temperature or how wide the throttle is open or anything else, and as you'll see, that can negatively affect control. of boost, so let's say you wanted to generate more boost than the spring inside your actuator has. How would you do it well? Of course you would fool the spring and the easiest and cheapest way to do this is with a manual boost controller. A manual boost controller is an extremely simple device that is installed in-line between the boost pressure source and the wastegate actuator.

It usually features some type of manual adjustment. There is often an adjustment knob on the top of the manual boost controller. Inside it is a small ball and a small spring that changes the setting of the manual boost controller changes the amount of spring pressure exerted on the small ball and what the small ball actually does is delay the boost pressure from reaching the wastegate actuator because the small ball requires more pressure than the wastegate actuator to lift from its seat. This forces the turbo to generate more pressure to lift the automatic bowl off its seat and reach the wastegate actuator.

Installing a manual boost controller is very simple, typically taking 10 to 15 minutes, but achieving the desired boost typically takes much longer. It takes trial and error and a lot of slow incremental adjustments, but when you combine a manual boost controller with an aftermarket wastegate actuator that can house different springs inside, it really has the potential to change the nature of your turbocharged engine, but as you will see it is far from perfect, although it increases boost the manual boost controller doesn't really do anything else, like our previous level 1 setup, the manual boost controller is dumb, it doesn't reference anything other than pressure of boost and there is nothing to control the manual boost controller and what can happen. with a manual boost controller is that you can sometimes achieve maximum boost with half throttle and while this may seem cool, it's not actually because it takes away your ability to modulate the power, which means that driving the car can be very difficult, another problem with manual impulse. drivers is that they may require frequent resets.

A setup that works at one temperature and elevation may not work at another. This problem can be especially pronounced if you drive your car year-round in a place with hot summers and cold winters. The reason behind this. Again, the manual boost controller is dumb, so it can't compensate for changes in ambient temperature or ambient pressure. At the end of the day, it's just one more spring delaying the compression of the original spring, so again you end up with only one spring. boost value that cannot be changed or controlled while driving now we are finally taking it a step further and electronics are coming into the picture and what you can see here is a 2 port electronic boost control solenoid and just like any solenoid. features a coil of wire wound around the ferrous metal when current passes through the wire it creates a magnetic field that moves the ferrous metal in essence a solenoid converts electrical energy into work or mechanical motion in the case of a impulse control solenoid A plunger of some type is usually attached to the ferrous metal and the plunger opens or blocks a passage through which pressurized air from the turbocharger flows.

A two-port solenoid is usually connected between the boost pressure source and the wastegate actuator with a T-connector and that's what it really does. bleeds pressurized air away from this hose which reduces the pressure inside the hose and this means that the wastegate actuator spring actually feels less pressure than the turbo generates, this then forces the turbo to generate more pressure than the wastegate actuator spring actually has. To open the wastegate, a solenoid now has two main advantages over any manual boost controller. The first advantage is that it is connected to an ECU. The second is that the amount of air it bleeds from the system can vary.

Now you may think of the plunger inside the solenoid as being open or closed, in reality what the plunger does is it moves rapidly between the open and closed positions, doing so many times per second, now the amount of time the driller spends in the open or on position within a single second represents the beauty cycle of the solenoid, the longer the solenoid is energized or the longer it is in the open or on position, the more air it will bleed from the system, meaning the actuator spring will see less pressure which will cause it to open later and this will allow the turbo to generate more boost now because the sauna is disconnected from the ecu the ecu can manipulate the duty cycle of the solenoid to manipulate the amount of air that is bled from the system and thus increase the pressure now the ecu references a bunch of different parameters meaning it controls the boost pressure based on those parameters for example the ecu can manipulate the duty cycle of the solenoid until it reaches the desired pressure in the intake manifold and because the ecu also references the throttle position, it means that you will never again experience the full boost problem at half throttle with an electronic boost control solenoid, the ECU also refers to intake air temperature and coolant temperature, meaning your performance will not vary as it would with a manual boost controller, as you can see from the 2-port electronic solenoid.

It solves two main drawbacks of the manual boost controller: it can increase the pressure a lot and thanks to the ECU it can increase the pressure based on different important parameters, but the two port solenoid still has one major drawback and the drawback is the way it is connected to the system, as you can see it enters the system and this results in the wastegate actuator spring continuing to see boost pressure all the time, the solenoid is simply bleeding air from the system, it is not breaking pressure of boost coming from the turbo, which means it cannot prevent the wastegate from opening at lower boost pressures than desired for a method that actually cuts off the boost pressure coming from the turbo we need to go up to level three enter the throttle solenoid. 3 ports the working principle is the same because this 2 is a solenoid, but the connection and obviously the number of ports is no different than the 2 port solenoid which needs a T connector to connect to the system.

The three-port Sony does not need a T-connector, it is connected directly to the boost reference line and actually interrupts the boost pressure passing through this line. The three-port sonar can do this because it has an additional port that vents the pressurized air to the atmosphere or back to the turbo inlet, as you can see here. The three-port solenoid is connected to a single-port internal wastegate actuator, but you can also connect it to a 2-port external wastegate or 2-port internal actuator. When the 3-port solenoid is energized, it interrupts or blocks pressurized air going to the actuator spring directly shutting off the air.

And by venting to the atmosphere, the three-port solenoid can keep more boost pressure out of the actuator, meaning it can help your setup generate more boost. Typically a three port solenoid connected this way will allow your turbo to generate twice the boost pressure than your actuator spring is rated at 11 psi, so if you are using an 11 psi spring like this which uses a 3 port solenoid can generally generate around 22 psi of boost pressure, twice the boost pressure is usually the limit because beyond this point what often happens is that the actual exhaust gases generated by the engine itself will overpower the spring and open the wastegate.

Additionally, because the 3-port solenoid interrupts the pressurized air directly instead of bleeding it, you get a turbo that is more responsive and faster, is more precise and requires less duty cycle to achieve the same boost pressures in Compared to a solid 2-port, which means it can give you more room to increase boost pressure and power Combined with an aftermarket wastegate actuator that can accommodate different springs, a 3-port solenoid will give you a lot of flexibility and plenty of room to grow AEM's 3-port boost controller solenoid is designed to resist corrosion and sticking due to exposure to rich fuel mixtures and is pressure tested to 100 psi, meaning it's ready even for the most extreme racing environments and the highest turbo pressures, it also includes high quality barb fittings to reduce the chances of leaks and a filter that prevents formatter or moisture from entering the controller.

Now for this level, we use the same hardware, but we connect it differently in our previous level. In the scenario, we have shown a 3-port solenoid connected to an external 2-port wastegate like this. Now a two-port external wastegate is great because it allows you to put pressure on both the top and below the spring, allowing you to better manipulate your wastegate. The connection type is fine, but it works very similar to a single port actuator connection. Once the boost pressure increases enough to overcome the resistance of the spring, it will compress the spring from the bottom and lift the external wastegate, so that's fine. but what we're essentially doing is just spring-loading, we're bleeding air from the system, and while a three-port solenoid is better for spring-loading, it can breathe more air and it can do it with less duty cycle.

Compared to a 2 port solenoid, there is a better way to connect a 3 port solenoid to an external 2 port wastegate and you will connect it this way as you can see that a boost pressure source is connected to the bottom of the spring and the 3 port solenoid, you're probably already thinking, hey, this is stupid, you're putting boost pressure directly on the spring, it'll just open the wastegate as soon as the boost pressure is high enough. high, but wait, the boost pressure will also increase. hesolenoid and from there to the top of the spring and what we are doing is using the solenoid to vary the amount of pressure received by the top of the spring in our previous level four scenario, we bleed the pressurized air coming from the turbo in order to manipulate how much pressure was available to open the wastegate, but in this scenario we are manipulating the amount of boost pressure that helps the spring keep the door closed.

Now let's imagine our external wastegate spring is set to open at 15 psi if the ecu manipulates the solar duty cycle to vent all the boost pressure reaching it then no boost pressure will reach the top of the spring , which means it will not get any help to counteract the boost pressure coming from below and will open the wastegate by compressing once the boost pressure reaches 15 psi, now let's imagine the ECU manipulates the solenoid to vent only 5 psi of boost pressure, this means that 10 psi of boost pressure will reach the top of the spring. Now our spring becomes a 25 psi spring, it has its own 15 psi of resistance plus the 10 psi of help it gets from the solenoid, now making the spring stronger is better than lying to the spring because the spring doesn't just fight against the boost pressure, but also fights against the exhaust gases pushing on the wastegate.

To open it, this is often why leaning on the spring cannot prevent the combination of exhaust gases and boost pressure from slightly opening the wastegate before you want that to happen. When you strengthen the spring, you are not just reducing the forces. By trying to open it you actually actively counteract them, ensuring that the spring does not open at all until the boost pressure is reached and of course this noticeably improves turbo traction and makes the turbo more responsive. Now imagine combining this powerful setup. with a very powerful ecu like the aem infiniti series 5 for example now this thing is not just lightning fast, but it has many boost control strategies, it can control boost based on rpm, throttle opening, manifold pressure, intake air pressure, flex fuel content, whatever, whatever, but you can also control boost based on the gear and speed of the vehicle, which means if you provide it.

With a vehicle speed input in the form of an ABS sensor or a transmission-based speed sensor, this can limit boost in lower gears, meaning it can help very high horsepower vehicles or vehicles with front-wheel drive to retain traction even in the lowest gears. which dramatically improves drivability, so a powerful ecu with a good 3 port solenoid and an external wastegate is a pretty much perfect combination for any application, so I just said that a 3 port solenoid and a good ecu is practically perfect for everyone. Why am I talking about a four port solenoid? Well, even a 3 port solenoid has its limits and although these limits are reached only in fairly extreme cases, there are limits.

However, as we said, a 3-port sonar can help you generate twice as much thrust. pressure rating of your actuator's spring, so if you have a 10 psi spring, then a 3-port weld can help you generate 20 psi of boost pressure. Now what you need to remember is that your spring is inside your external wastegate or internal weight kit. The actuator will always be the lowest amount of boost you can make, there is no boost control setting in the world that can help you make less boost than the spring has, so let's imagine you want to make 60 psi of boost, if that is. 4.1 bar which is obscene boost but you want it anyway and you grab your ECU and your three port solenoid and you know since you want 60 psi of boost you need a 30 psi spring so you grab your 30 psi spring and do it you install inside. your wastegate actuator and you feel really good about yourself, then you take your car and try to get it off the starting line and all it does is spin the tires, so why does this happen?

It's happening because 30 psi is the minimum boost you can do and your setup is to do it in first gear, second gear, two, so unless you have giant ultra fat tires or a stupidly advanced all-wheel drive system, you just created a exhausted monster that has a stupid looking boost curve, so how do you fix it? This madness enters the 4 port boost control solenoid with one more port, it can do something that the 3 port solenoid cannot: it can manipulate both the top and bottom of the wastegate spring when energized and its maximum duty cycle. will send boost pressure to the top of the spring, helping it stay closed, and at the same time vent pressure from the bottom of the spring, meaning the chances of a crack opening are virtually zero when is de-energized. increase pressure at the bottom of the spring and vent from the top of the spring, ensuring instant opening of the wastegate when needed, so let's get rid of our ridiculous 30 psi spring and replace it with a 10 spring psi to regain traction in all gears now.

The turbo begins to build boost and the ECU energizes the 4 port solenoid so that it diverts the maximum amount of boost pressure possible to the top of the spring and vents from the bottom of the spring at the same time, this means that when the turbo really boosting boosting the bottom of the spring sees virtually nothing at high duty cycles this is close to atmospheric pressure, on the other hand as the turbo generates more and more boost it more and more helps the spring stay closed, as you can see this is a pretty aggressive scenario where the spring doesn't move at all until the solenoid allows it.

That's why a 4-port Zoner makes it easy to reach the surgical limit of your turbocharger and has extremely aggressive boost response. In fact, a 4-port solenoid is actually capable of controlling the system to generate 5 or even 6 times more boost pressure than the spring has, giving you an absolutely gigantic boost range and helping power vehicles extreme at regaining traction in lower gears, so this is perfect. we all want well, unfortunately the 4 port zone also has a drawback and its drawback actually comes from its strength because the 4 port solenoid controls both the top and bottom of the spring at the same time, changing the duty cycle can change significantly. affects the resulting boost pressure when you change the duty cycle on a 4 port solenoid, it removes the boost pressure from the top but at the same time sends it to the bottom of the spring or vice versa and this significantly affects the boost pressure .

This is also why many people say that four-port solenoids have poor resolution, what they really mean is that when you change the duty cycle by just one or two percent, you change the boost pressure. between three and eight psi and that's why Four-port solenoids often produce a pretty erratic or bumpy boost curve, so how do we fix that? How can we improve? We do this using two three-port solenoids. Two three port solenoids can give you a giant boost level but also a pretty smooth level and linear boost curve, but they require a very complex, very advanced, very high end ecu that can control them and some very clever and complex tuning, so So in short a 3 port solenoid along with a good ecu and a 2 port external wastegate. or a 2-port internal wastegate actuator will fit 9 out of 10 applications.

This is an extremely versatile, very flexible and very powerful boost control setup. It can provide you with excellent turbos. Get excellent turbo response. A linear boost curve and can also give you. On the other hand, quite a bit of boost, dual-port solenoids and manual boost controllers, while inexpensive and easy to set up, are not capable of harnessing the potential of modern turbochargers and well-built engines if boost is what you're looking for. giant. extreme levels and horsepower, then one four-port solenoid or two three-port solenoids are the way to go, so there you have it, that's it when it comes to boost control

setups

.

I hope this video managed to clear things up and help you visualize the type of boost control setup you want for your vehicle, as always, thanks so much for watching and I'll see you soon with more fun and useful stuff on the d4a channel.