Forge Manual Boost Controller Adjustment

I just installed the Turbosmart manual boost controller on my MSM, replacing the one that came with the FM intake kit. I like the look of the boost controller, but not sure I am pleased with where I have it located currently.

It comes with a little L shaped bracket that I used to mount it at the front of the valve cover using the bolt that held the stock boost controller. If others have installed this controller, let me know where you chose to locate it. My real question though is concerning the setting. I had backed the controller all the way out and then turned it 4 clicks to start out. On the first drive, I was hitting 11.5 psi in third, so I stopped and adjusted it back to just two clicks, which put me at 9 psi in 5th at WOT. I then turned it to 3 clicks and it hits 10 - 10.5 in 5th at WOT. That is fine, and where I want it to be, but my concern is when it gets cooler, will I have enough adjustment to bring the boost down to that same level?

Anyone using this controller and have any input? 05 Black MSM, OEM hard top, FMII conversion, Inconnel studs, Garrett GT2560R, FM crossflow, FM Stage 2 fans, MS3X, I.D. 1000cc injectors, Hallman RX PRO MBC set at 10psi, Full FM exhaust, Ebay FMIC, Forge BOV, FAB 9 COP conversion, Walbro 255 LPH fuel pump, GTX PCV valve, Gates blue racing belts, EBC delete resistor mod, Racelands, FM frame brace, HDHCDD HT roll bar, HD harness bar, Schroth 4 point harness, Lotus Exige seats, TDR SS clutch line, Spec stage 3 clutch, Beatrush PPF bar, FM sway bars, Advanti Storm S1's 15x9's, 949's Adj.

End links, Fog light grills, Buddy club cubby, LED map light, LED licence plate lights, Nautilus Stebel Air horn, Miata Roadster Short shifter, Innovate DL-32, MTX-D, LC-1, 2ea. Larry4 Miatas but who's counting!!White Knight 1991 Crystal White #99 CSPSilver Bullet 1992 Silverstone #17 SM2 FM I+ Turbo (Gone but not forgotten)Honey B 1992 Sunburst Yellow #99 SM2 J.R. M45Whooosh 2004 Titanium MazdaSpeed MX5 #403 of 4000Subie 2006 Steel Gray WRX STi Cobb Stage 2 (Gone but not forgotten)No name yet 2008 Velocity Yellow Tintcoat Z06 CorvetteNo Name yet 2014 Ashen Grey Metallic Camaro 2SS 1LE“There are only three sports: mountain climbing, bull fighting, and motor racing. All the rest are merely games.”– Ernest Hemingway. Larry4 Miatas but who's counting!!White Knight 1991 Crystal White #99 CSPSilver Bullet 1992 Silverstone #17 SM2 FM I+ Turbo (Gone but not forgotten)Honey B 1992 Sunburst Yellow #99 SM2 J.R. M45Whooosh 2004 Titanium MazdaSpeed MX5 #403 of 4000Subie 2006 Steel Gray WRX STi Cobb Stage 2 (Gone but not forgotten)No name yet 2008 Velocity Yellow Tintcoat Z06 CorvetteNo Name yet 2014 Ashen Grey Metallic Camaro 2SS 1LE“There are only three sports: mountain climbing, bull fighting, and motor racing.

All the rest are merely games.”– Ernest Hemingway. Thanks schmoo. I'm assuming you are using the turbosmart MBC as well. Last night I was hitting 10.5 at 3 clicks from the 'off' position so that is why I am concerned that when the temps get low there won't be enough adjustment to dial it back. I guess if the 'off' position is actually like a direct connection that it really should then only boost to 7.5 psi, right?

I'll play around with it more this evening and see how it behaves. Thanks for the responses folks.Do as SMR suggests. Sounds very weird.

It was brought to my attention that we don't have anything on the forum describing boost control, how wastegates work, and how to 'turn up' the boost. If someone searches for this info, they shouldn't come up blank anymore. Also, there are tons and tons of myths when it comes to boost control especially comparing manual to electronic. I want to shed some light on those as well. I wrote a lot of this during a debate on a BMW forum and copied it over so it might not flow as well as I'm used to. I'll work on it.How common wastegate actuators work.Here is an external wastegate for reference.Internal wastegates have external actuators, so there's nothing fundamentally different about them that makes one different from the other when it comes down to the actuator.

Internal wastgate actuators have the same diaphragm/piston/spring layout that external wastegates do.The major difference being, no internal wastegate actuators you're going to run into will be serviceable, meaning the spring can not be changed. External wastegates by-and-large have a serviceable design. This means you can open it with common tools, and change the spring inside if you'd like. This spring is what holds the wastegate closed during operation. You have to fight against this spring with positive air pressure from the 'compressor reference port' to get the wastegate to open. When the wastegate opens, exhaust gases bypass the turbine and boost is limited. Simple enough.Typical internal wastegates do not even have a 'boost controller port' and this port is usually left open (to atmospheric) on external wastegates.

It is commonly used with electronic boost controller setups, but I'll get to that later.The wastegate spring.This spring comes in different flavors. Most factory wastegates are internal, with their springs set anywhere from 6-12 psi. Some, like the newer Mitsubishi Evolutions have 14.5 psi or higher springs (very high for a factory car). In turbo Porsche cars, they tend to use external wastegates, again with the springs ranging from 6-12 psi depending on year and model.Simplifying things a little bit, the lowest amount of psi you can run depends on the wastegate spring. If it takes 6 psi to compress the spring, you can't make less boost than that because you're going to be using the pressure from the manifold to work against the spring. As you start to make 6 psi to the manifold (and the engine) your wastegate actuator will see 6 psi, and start to open the wastegate (it happens earlier than this, but don't worry about that).

Now that the wastegate is open, some exhaust gases are 'wasted' and not used to spin the turbo. This limits boost pressure to the amount dictated by the spring (provided you have enough flow in your wastegate system).Controlling boost with the wastegate spring.One, expensive, complicated, limiting way of raising the amount of pressure the turbo outputs involves swapping the low pressure spring in an external wastegate to a higher pressure spring. This gets expensive and time consuming if you're looking to move from low pressure to high pressure in stages as most tuners like to tune in stages.

Once the high pressure spring is in, there's no simple/quick way to run lower boost pressure either (valet mode, etc).All in all, it's a pain in my opinion, and most people don't do it this way. They get the lowest pressure spring they can (to allow for low boost) or they just work with what ever comes with the wastegate.Traditional boost control theory.Here's where the other methods of boost control come in. You can fool the wastegate actuator into opening at higher air pressures than the spring is designed for by controlling the pressure signal the actuator sees (connected to the 'compressor reference port').

This can be done many different ways regardless of internal/external design. There are three main ways of doing this.Bleed method.Firstly, you can 'bleed' off some of the signal to the wastegate with a controlled leak in the pressure line going to the actuator. This method is simple and marginally effective and usually overlooked as the next example is better and no harder to implement. The bleed can even be an adjustable valve that is controlled inside the cabin. 'Dial-a-boost' they like to call it. This is one method of manual boost control.

Many say manual boost controllers cannot be controlled from inside the cabin, which is untrue. This method can be employed typically for $15.Traditional manual boost controller.The next method involves a one-way ball-and-spring check valve. This is what is typically referred to as a 'manual boost controller'. This is placed in the signal line. The device has an adjustable spring inside which takes over the job of the original actuator spring.

Set the pre-load on the spring to what ever psi you'd like and the wastegate actuator won't see any pressure until that level is reached. This method is simple, cheap, and marginally configurable (adjustment can also be routed into the cabin for control from inside the car). Even set at the same psi as the original wastegate spring, this method gives quicker spool than normal, as it doesn't allow the wastegate to 'creep' open before the desired boost level is met, causing full boost to come on quite a bit sooner.Many people believe this method is flawed or unreliable, causing dreaded boost spikes and the like. While I don't doubt others have experienced this, I know with a properly set-up turbo system, there should be no problems. I've never experienced boost spikes on the 6+ turbo systems I've helped with or friend's of mine have, all using this method. My experience ranges from tiny, internally wastegated Mitsubishi turbos to large gt35 turbos, all on 2.7 liter or smaller engines.This method can be employed typically for $35 if you build your own or around $80 if you buy a fancy (but no better functioning) one.Traditional electronic boost control.The third main method involves controlling the pressure signal to the wastegate with an electronic valve, controlled by an electronic controller of some type.

This typically gives complete control over the operation of the valve and thus the wastegate actuation, but requires a bit of set-up time and quite higher start-up cost as the electronically activated valve runs about $50 and the controller itself can range from $150?-$600 or so. Engine control units typically have this control functionality built in, making this cost a non-issue for some.With this method, you can control how quickly, or how slowly boost comes on. Allowing for boost to build progressively through the rev range if desired, and allows for the control over the maximum boost depending on what gear you're in (if your controller has that functionality). There is no limit to what you can do with this set-up, paired with a good controller (except you can't run less boost than what your wastegate actuator spring will allow).

However, most find this method overkill, or unneeded for their goals.Traditional electronic boost control. (Expanded edition)There are three typical methods of connecting the electronic solenoid.In the first example the solenoid is plumbed in such a way that it acts as a valve that is open until you close it with an electrical signal.

Electronic Boost Controller Install

Close the solenoid with an electrical source and the wastegate doesn't see pressure and stays closed. Allow the solenoid to open and the wastegate sees pressure and opens. This control method does not absolutely require a 'controller' and can be operated by a pressure switch.This method is fail-safe. If the solenoid or control method fails the solenoid will not block flow to the wastegate and the system will not prevent uncontrolled boost levels.If you connect the boost source to the other solenoid input, it can work that way as well, but it will not be fail-safe.As described in the picture, this method can allow boost onset to happen faster than normal.In the second example the solenoid acts as a pressure bleed in the system. The amount of pressure bled off will need to be controlled by a tunable 'controller' to maintain the desired boost level. With this method, boost onset will happen at normal speeds. Contrary to the diagram, there is no need to plumb that line into the turbo intake, it can just vent to atmosphere.This method is fail-safe.

Manual Boost Controller How It Works

If the solenoid or control method fails the solenoid will close the bleed and the boost level will return to that dictated by the wastegate spring pressure.The third example is the most commonly used and recommended method. The solenoid, when at rest (closed) in this configuration blocks flow to the top of the wastegate so no pressure reaches the top. This means the full boost pressure will work against the bottom of the diaphragm and the system will maintain a boost level based on the wastegate spring.

Forge Manual Boost Controller Instructions

If the solenoid is opened with an electrical signal then the pressure at the top and bottom of the wastegate diaphragm is equalized. With the pressures equal the wastegate spring is easily able to hold the wastegate closed so the wastegate will never open. This would allow for uncontrolled boost.What happens then, is that the solenoid is opened and closed very quickly (60-250 Hz or there about) but it spends more time in the open position than it does in the closed position. This creates a situation where you can vary the amount of pressure provided to the top of the wastegate to 'help' the spring. If you have a 7 psi wastegate spring and you want to run 8 psi with this method, the controller needs to open and close the solenoid in such a way that only a little bit of pressure makes it through to the top of the wastegate. If you want to run 30 psi the controller needs to spend a lot more time 'open' to allow more pressure to the top of the wastegate to 'help' the spring keep the wastegate shut against the pressure.This method is fail-safe.