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The Boost Enhancer is a simple yet precise and well thought out adjustable boost pressure relief valve.
The Boost Enhancer brings on the boost in the Porsche 951 (944 Turbo) earlier. Much earlier.
CAD designed and CNC machined from 6061 Aircraft Grade Aluminium with a red and blue anodised finish.
The Nylon Poppet with Nitrile Rubber Seal rides in a cylinder style bore maintaining a perfect re-seal
every time the boost comes back down. With a full 1/4" bore for maximum signal flow to
Wastegate when needed.
This device completely prohibits airflow to the Wastegate until you want it.
Boost Enhancer Explanation and Adjusting (1)
The following is an explanation of how and why the Boost Enhancer works. Once you understand the basics of the 951 Wastegate system, you will see the necessity for the Boost Enhancer. First, let's explain the basics of turbo charging. Since a turbo is an exhaust driven device, the more pressure you build in the exhaust system, the faster the turbo spins up and the less lag time there is. Keep in mind that the typical turbo spins over 50,000 rpm at full pressure. The turbo takes time (lag) to reach this speed so the more exhaust pressure applied to it, the faster it will reach the necessary rpm to produce full boost. The waste gate is the device that regulates the speed of the turbo, otherwise with enough pressure the turbo would over-rev. This is a bad thing!
There is a diaphragm in the waste gate that contains the pressure and opens an exhaust valve inside that relieves excess exhaust gas pressure to slow the turbo down. This basic concept is used on virtually all turbo charged applications. The waste gate has a connection to the intake system that feeds boost pressure to it. This is essentially how the system works. The banjo bolt on the boost tube is where this connection to the waste gate takes place. Most people, even factory mechanics, are not aware of this fact: The factory design of the 951 Wastegate is such, that it opens as soon as any pressure is introduced. It might be barely open, but open none the less. The higher the boost pressure goes, the more it opens. The problem is it is dumping valuable exhaust pressure to drive the turbo, before it has to! More boost at a lower RPM means more torque and horsepower in that RPM range. Who knows why Porsche did this! Perhaps it was to make the car less of a handful and a little easier for the average person to drive. Remember the 951 was close to 911 performance. The 911 was more expensive with similar peak horsepower.
The solution to this problem is to slow or completely stop the air signal to the waste gate as long as possible. Most of you with stage 2 software have the modified banjo bolt that was supplied. This device has a restriction jet that slows the boost signal to the waste gate. It works well, but it only slows the boost reaching the waste gate. Why not stop it all together? That's where the Boost Enhancer comes in. This device does exactly that, it stops the boost signal until a pre-set pressure is reached, then full boost is applied to the waste gate and factory systems operate normally from that point on! It's not intended to allow you to build higher boost pressure, but to give you your normal level of boost much sooner. Once the Boost Enhancer is fully open, the factory controls for timing, fuel, knock control and maximum boost are still there, it is not intended to over ride them. Factory setting on the Boost Enhancer is 10psi. It requires 10 pounds of boost pressure to start to open it. The higher the pressure it receives, the further it opens and the more it flows air to the Wastegate. This setting is suitable for most cars including standard and chipped (up to 1 bar (15psi) of maximum boost) . The operation and adjustment apply to both 220bhp and 250bhp models.
We highly recommend that if you have the banjo bolt with the air restrictor, remove it and install the factory bolt! The reason for this is that once the Boost Enhancer opens, you need to get the boost to the waste gate as soon as possible. There is no more reason to delay it any longer! (This applies also to bleed off valves fitted after the timing or cycling valve; supplied with some performance chip upgrades) For street applications, there is really no advantage in changing the factory setting of the Boost Enhancer. We have already set it at the optimum pressure for safe operation. The speed of the turbo increases exponentially. In simple terms, the time it takes the turbo to build 4psi, it can go from 4 to 16psi just as fast. So if you set the Boost Enhancer too high, the turbo can spin up so fast that it could over-boost. The Factory computer will shut the engine off if this takes place, so you won't blow the engine. The 10psi-factory setting gives the waste gate time to regulate the turbo like it needs to. If you have a race car running significantly higher than normal boost pressures, a slight gain might be had by "Tweaking" the setting.
Boost Enhancer Explanation and Adjusting (2)
The following is an explanation of how to adjust the Boost Enhancer. The inner workings of the Boost Enhancer are as simple as it's function. It contains a valve and a spring. The more pressure you apply to the spring, the more pressure it takes to open the valve. It is factory set at 10psi. Beyond 10psi of boost, the valve starts to let air through the Boost Enhancer and down to the waste gate. The Boost Enhancer pressure should be set at 5psi less then the total boost you normally run. If running 15psi of boost, the boost Enhancer should be set at 10psi (it's factory setting). That allows a 5psi window of time for the signal of air to open the Wastegate properly and eliminate over boosting or boost spikes.
The housings of the Boost Enhancer screw together like a nut and a bolt. Right hand threaded. Once you loosen the "Jam" nut (the thin red nut) from the Inlet Housing (Blue Housing) you can screw the Outlet (Red Housing) in and out freely. One revolution equals approximately 1 psi of pressure. Tighten in (clockwise) one turn for one additional pound of pressure and loosen (counter clockwise) one turn to lower one pound of pressure. Two turns equals two pounds, etc... etc... After turning the housings to the desired position, you need to tighten down the "Jam" nut back against the Blue Housing. This locks the two housings back together again.