Overboost protection and why it’s important

At Stratified we have recently launched a product called the Guardian Angel which is an overboost protection device for any gasoline fueled turbocharged vehicle.

We get a lot of questions about what such a device does and how it is better than the fuel/ignition cut that is available in most ECUs – so I thought I’d highlight how such a device can be effectively used.

The first thing to remember is that this device is DECOUPLED from the ECU as well as the boost control (both mechanical and electronic) system installed in the car. This makes it a true safety net should something happen.

For example, if a wastegate line pops off, the control system may reduce wastegate duty cycle, may initiate fuel cut, or may do both. However these responses often have delays built into them and do not IMMEDIATELY release boost pressure at the manifold which is what the Guardian Angel does. Whether your wastegate is not working, lines pop off, or you’re playing with the car’s tune and miss a number, the Guardian Angel will always be watching over the vehicle’s boost and preventing a catastrophic condition which often leads to a blown motor or bent rods. The rods below were bent from a 30psi boost spike on a Mazda DISI motor. The ECU just couldn’t react quickly enough to prevent the damage.

We’re not all expert tuners and most importantly we all make mistakes (even the pros) with the installation of parts and tunes. Parts fail all the time – at my most recent dyno day we had a wastegate line pop off that caused a 30psi+ spike – not something healthy for the motor. The last thing we watch at a track day is the boost gauge and this is what the Guardian Angel is constantly doing. It takes the worry out of driving the car in all conditions, installing new parts, and modifying tunes.

The Guardian Angel is easy to install and it works with any ECU or turbo configuration as long as the car is equipped with a push type/piston or diaphragm bypass or blowoff valve. So you can take this from a Mazda to a Honda to a Toyota and it will work the same way. If the device is triggered, you get a visual indicating (via the LED) and the overboost protection is a very gentle one. The ECU can only cut fuel/spark which is very hard on the motor and drivetrain. The Guardian Angel reduces boost but still allows you to keep your foot in it should you be in the middle of a pass for example. Last thing you want is to lose all power with incoming traffic. The Guardian Angel gives you the option to investigate the overboost condition when it is safe. See it in action in the videos below.

As an additional feature, we offer a external trigger for the Guardian Angel. Water/Methanol injection users that have failsafes try and reduce boost using the wastegate if the system fails or tank runs dry. This can be slow and if the wastegate fails it will be ineffective. Instead, you can attach your external trigger wire to the Guardian Angel from the WMI controller or any other ECU.

There have been a few independent review and install articles for the Guardian Angel and these are posted below. Remember that this device is universal to all turbocharged gasoline engines. If you have any questions, please Contact Us.

Guardian Angel Install and Review

Guardian Angel Install

Happy and safe boosting!

The Stratified Team