6 Reasons for Using an External Waste Gate
Push Turbo is the first to offer an external waste gate. The waste gate is the brains of the turbo system as the turbo is the heart. The 6 reasons for using an external waste gate are overwhelming.
1. You can run a smaller exhaust housing because not all of your exhaust is going through it like an internal waste gate. This allows for 2 things, less weight and more importantly…a faster spool up time.
2. The valve has a seat where the internal waste gate does not causing it to constantly bleed. A bleeding waste gate causes slower spool up time.
3. With the waste gate outside the turbo housing you get a nice, clean arrow dynamic flow through the housing and the turbine. With an internal waste gate the flow is choppy inside and washes out the turbine wheel flow on the outside. This is why some turbo kits try to separate the waste gate exhaust from the turbine exhaust. Although they may see a good horse power gain, it does not help the choppiness inside the housing which causes the slower spool up time.
4. Valve speed can be ten times faster than an internal waste gate. What this means is your on off throttle response is very clean and instant boost when back on the gas. Internal waste gates are slow because of the linkage and actuator size, causing poor on off response. A good diagnosis of this is you think your blow off valve is not working properly slowing your response time down. While this is partly true it is very bad not to run a blow off valve. Not running one will damage your turbo. This is what should be going on. You get off the gas causing the blow off valve to open and the waste gate to close causing the turbo to speed up for an instant and actually flowing more boost air. There is no resistance in the charge tube (air is free flowing out the blow off valve). Next you get back on the gas, the blow off valve closes and the waste gate is closed causing instant boost and all is well. This is what will happen with an internal waste gate. You get off the gas, the blow off valve opens, the waste gate slowly starts closing and your turbo does not get that extra turbo speed (all flow and speed is lost). You get back on the gas, blow off valve closes, and you slowly build boost. If you do this a few times in a row it becomes very apparent. If you disable the blow off valve it would improve your throttle response in this quick on off situation but will also damage the turbo at the time. As you can see an internal waste gate is beyond it’s capabilities in this application.
5. Boost pressure is held much better because of the valves bigger size, speed and capability to seal. What this means is you are not fluctuating boost pressure like an internal waste gate or momentarily over boosting. This will make drive ability much smoother when varying the throttle position in a technical riding situation.
6. As you can see the waste gate is the most critical component in the system. It is not a place for compromise where performance is sought out.