Electronic Boost Controller Comparison Chart
 

Perrin has a great introduction to boost control systems in their article Boost Control Explained. The OEM Mazda system uses a 2 port solenoid system and these aftermarket controllers mostly use a 3 port solenoid.

A common question asked is, “Which electronic boost controller should I get?” A lot of that comes down to price and preference. Believe it or not, aftermarket external electronic boost controllers tend to be pretty similar across makes and models. The components are similar, the control systems are similar, and the process of tuning the controller is also similar. Here I am presenting a comparison chart between the most common aftermarket electronic boost controllers currently available. To illustrate how similar many electronic boost controllers really are, the chart shows the different names each model uses for basically the same type of setting or function. For example, the AEM Tru Boost adjusts the wastegate opening pressure with the “SPr” aka “spring” setting. The Greddy Profec B Spec II adjusts the wastegate opening pressure with the SET GAIN aka “Start Boost” setting. Some controllers have functions completely missing: AEM Tru Boost doesn’t have a feedback setting, and the Blitz controllers do not have a wastegate opening pressure setting. Make sure you read the instructions of a particular boost controller before you go using it.

Although it is not a separate boost controlling device, I did put the Power FC into this chart because its boost control system is simple to adjust. I did not include other standalones such as Haltech and AEM EMS due to the complexity of setting them up. I also didn’t include the old Greddy Profec B and the older HKS EVC units (anything besides EVC-S) because they use stepper motors and that is not a common design anymore.

Basic Settings

Baseline duty cycle - this is a value usually from 0 to 99 which sets a baseline ratio of ON to OFF time for the solenoid. The boost controller rapidly cycles the solenoid. When the solenoid is ON, it is operating in a way that works to keep the wastegate shut . A higher value here corresponds to higher boost levels. You should start near 0 for this setting.

Wastegate opening pressure - This is the pressure at which the wastegate is allowed to open. If the current boost level is below this value, the gate will be stay shut. The higher you set this value, the more you will improve your spool, but at an increased risk of spiking. If this value is set too high it can lead to spikes or oscillations. You should start near 0 for this setting.

Feedback – Without getting too technical, this is a correcting feature of the boost controller which usually 1) improves initial spool and 2) reduces the amount that the boost falls off at high rpms . If this value is set too high it can lead to spikes or oscillations. Feedback is NOT the same as “self learning.” Self-learning features basically attempt to do the work of tuning the controller for you. Feedback is actually another parameter for you to tune and should not be confused with self-learning features. You should start by setting this value at or near 0.

Overboost protection – This should not be confused with an overboost warning. Many controllers will illuminate or sound an audible alarm, but the alarm itself just alerts the driver of a problem. The overboost protection could be a completely separate or a separate but related function to the overboost warning.
On an external EBC the overboost protection function of the controller will disable the solenoid once a certain boost has been exceeded. The controller disables the solenoid in an attempt to bring boost down to the wastegate spring pressure. Each controller implements the overboost protection feature in its own way so be sure to read the instructions carefully. This disabling of the solenoid will not protect your engine in the event of a serious mechanical failure such as a stuck wastegate or a melted wastegate hose. On factory ECU’s or standalone engine management overboost protection is accomplished usually with a fuel cut. Unlike a solenoid disable, a fuel cut will protect your engine in the event of a serious mechanical failure in the boost control system.

Temporary boost increase – usually this is called Scramble Boost. It’s a feature that allows you to raise the boost for some number of seconds. It is implemented differently across manufacturers. This is the kind of feature you would expect Paul Walker to use when he runs out of NOS. In reality not many people set this up.

Boost target – On controllers with a Self-Learning mode, this is the intended boost pressure that the controller will try to reach using a self-tuning process. Apex’I uses this setting differently. The AVC-R can utilize a boost target setting even when Self-Learning is disabled. On the AVC-R the boost target is used as part of the regular feedback system, unlike other controllers. The AVC-R’s implementation of a boost target is closer to what you find in many standalones (AEM EMS) or programmable stock ECU’s such as a Subaru stock boost control system. The Power FC has a boost target setting but its actual real-world use is more like a rough adjustment of the feedback system.

Additional Features

Self-learning - This is NOT the same as a Feedback setting. This is a mode where the controller is supposed to figure out the settings for you, once you have picked a target boost and gone through a learning procedure. These features generally have mixed results at best. Personally I do not use self-learning modes because I feel that having someone competent adjust the controller manually will have a better final result.

Gear or Vehicle Speed based adjustment - This allows boost adjustments based on rpm or vehicle speed. Most commonly this is used as a form of traction control. These features are typically found on standalones but only a couple external electronic boost controllers have this kind of capability.

RPM-based adjustment - This allows fine tuning of duty cycle based on RPM. This could be used to keep boost steady at higher engine speeds.

After all that explanation here is the chart:

https://www.rx7club.com/attachment.p...1&d=1304450799

Note that some controllers combine two functions into one setting. For example, the Blitz controllers use the “Set” value as a boost target when in self-learning mode, but when in manual adjust mode the “Set” is a baseline duty cycle value.

Adjusting your boost controller

As a general strategy, when setting an electronic boost controller you should usually start with all the main settings (baseline duty, wastegate opening pressure, feedback) near 0. Configure your overboost protection setting. Now begin raising boost by alternate between increasing the baseline duty cycle and increasing wastegate opening pressure in small increments. Once you notice that the engine is slightly below the intended boost level, start adding in feedback until the target boost level is achieved and boost is relatively steady. From there you can make minor tweaks to the settings again. Every car is different but usually spikes or oscillations can be fixed by turning down the wastegate opening pressure or feedback settings.


In conclusion, the major external electronic boost controllers available today have the same basic system design. Some models have more or less features than their competitors, but all of them will get the job done as long as they are installed properly, tuned correctly, and used on a turbo system that is mechanically sound.

Good stuff!! I vote archive!!

I was thinking about EBCs, but settled on a Hallman MBC

As always, great info. I have never owned an EBC and have always wondered about this stuff.

How much more capable is the Profec S at controlling boost spikes than the power FC on the twins? Or is there any difference?

Seems they both have the same function ability although the Profec uses it's own solenoid.

So,what is the "best Bang for the buck"?
I'm trying not to spend the price of a car on my EBC!

Blitz Icolor FTW

Although the avcr is probably one of the most expensive units on the market i am glad i replaced my Greddy profecB specII with that.

Boost control is far superior!
With the greddy unit i always had boost spikes in 4th and 5th, therefore i had to lower the overall boost setting.
With the avcr it takes some time getting it right, but since you can adjust rpm/gear based, i get a steady 1.1bar all the time, in every gear
You can keep dutycycles as high as possible for better boost response

I wan to ask a question here too... which is a good valve/solenoid to use? I already have EBC in my ECU, I just need to program it.

Aha this is the topic I was aiming for. I have an EBC from Greddy and I cannot get it to work correctly.

My aim - target is 22 psi in 4rth gear and normally a bit less in 3rd ( say 20psi in 3rd )...

I dont use or race in 5th so I dont care about 5th gear...

So my mechanical WG spring boost is set at 18psi... No mater what setting I dial in in the EBC unit the end result is the same...

ie Set from 50 up to 78%
gain - from 5 to 15 %
start boost from 0 up to 1.1 bar

i cannot raise my target boost...All I get is annoying overboost-spicking... For example if I floor it in 3rd or 4th with low rpm ( say 3500-4000rpm) I get close to 25psi boost spike and the boost limiter of my Power Commander kicks in and stalls the engine but if I do a quarter mile from a standing start with the same settings I only get about 20psi and only in 4rth gear
( remember that my WG spring is set to 18psi )

So imagine this. 18psi mechanical pressure , 75% duty and all I get is a 2psi raise in boost. This is when changing gears at 8200 rpm

My WG spring boost is 18psi in 3rd and 4th gear and it stays there all the way up to redline so I assume that this means I dont have a diaphram leak or a weak spring...

What is wrong??? I have changed all my pipes , lines , hoses , checked for leaks , re checked the Greddy installation manual... All is done correctly and nothing works correctly

I have an HKS T04E with 56trim and a 40mm HKS WG

Please help

Is there a set up that will give me as LITTLE AS POSSIBLE over boost or spike and will only give a solid 22psi in 3rd and 4rth gear???

I linked you this topic a long time ago.
Put a manual boost controller in and see what happens, but again i had no problems with my wg until i tried for higher boost, that is when the diaphragm started acting up

When i went to change the diaphragm i noticed the bolts holding the wg together seemed loose so that might have been tnhe problem all along

So here is an update...I removed the external WG and had a closer look and there are no leaks and the diaphram is bang on. So there is something wrong with the setup ( despite me trying every possible setup ) , the selenoid has been cooked or my tiny HKS T04E cannot produce more than 21-22 psi...