Debunking Common Misconceptions about Manual Boost Controllers

The basic concept of an electronic solenoid controlling boost from your turbo, hasn’t changed since the 1970s.  Maybe that’s why we keep hearing new generations of engine tuners quoting the same misconceptions we heard in the 1980s.

This is a summary of some concepts discussed in an early post.  For more detail, check out this article.

I’ve been told that I can’t use a manual boost controller with my vehicle. Is it true that they don’t work on computer controlled engines?  No and anyone that tells you this is full of BS. In almost every case, the modern turbo is controlled by the same vacuum actuator that was used in the 1960s. The only difference is a solenoid is employed to “bleed” off the boost pressure to the actuator, allowing a higher boost level. It is the solenoid that is controlled by the ECU, not the vacuum actuator. You CAN employ a manual boost controller in concert with, or as a replacement to, the factory electronic solenoid control. We’ve done so on vehicles from the 80s, 90s, 2000s, 2010s, and expect to in the 2020s.  Porsche 911 Turbo, Nissan 280-300-GTR, Chevy Cruze, Nissan Juke, Chevy Sonic, Cadillac 2.0T, Ford Eco-Boost, etc.  All are using our manual boost controllers.

Can I use a Manual Boost Controller with my performance “chip”? Yes, although the gains will probably be of a lower magnitude than those of unmodified cars. This is because many chip manufacturers have already raised the boost to the upper limit of what the factory fuel system can support. Additional gains can be found by using the Boost Controller if the chip manufacturer allows the boost signal to reach the wastegate before peak boost is achieved. This is usually the case, as the factory boost controller cannot respond fast enough to control “spiking”. The result will be more area under the boost curve and more torque.

Will I Void My Warranty? Um Yeah! However, one benefit of a Manual Boost Controller is that it is easily removed should a warranty issue arise. However, we do not endorse this action as it would be dishonest…  Unfortunately, carelessly increasing the boost without monitoring air/fuel ratios or exhaust temperature may damage your engine. That said, most factory systems can take a 10-20% increase in boost without fuel problems. A good EGT gauge can help, to monitor your progress. Check the values at WOT at stock boost levels and then slowly increase the boost. When you notice a drop in O2 sensor voltage, or a rapid increase in EGT, you have reached the limits of your current fueling capabilities. You will need to add more fuel. There are too many ways to do this to cover here. This same risk is present with an electronic controller or a chip.

How high can I raise the boost?  Provided you have the fuel to accommodate the extra boost, as high as the boost controller will allow. That is usually in excess of anything the factory fuel system would support. Actual limits of the controller are dependent on variables, which include turbo size and wastegate actuator parameters. Keep in mind that some turbo systems will cut fuel delivery above a preset factory limit, usually 2 bar or 14.7psi.