| complexity of manufacture, the doolz Extreme with the bias plates was abandoned. The only function of the plates was to allow mechanical manipulation of the fuel delivery. The new version that is out today is revised from the original DOOLZ I released 7 years ago when I began working with Z1. I revised it a year later by reducing the cut into the sides of the pipes where they are joined together. The original shared area was larger than it needed to be and reducing the shared area still kept things in balance but increased the cross sectional area for more flow. The filter baffles (flower pots, or whatever you want to use) are not necessary in all cases, and the flower pot idea was simply an inexpensive solution for ANY dual intake system. When you split the total air going through the meter, you are effectively cutting its measuring accuracy in half. It doesn't matter if you have a DOOLZ, JWT dual pop, or Selin setup, you are still only putting 1/2 of the total airflow through the mass airflow meter. By doing this, you are increasing the effects of flow turbulence through through the sensor. When there is a larger quantity of air flowing through the meter, the effects of turbulent flow are basically drowned out. Having the filters exposed to any ram air is going to cause turbulence in the MAS - this even occurs in a single intake setup with fascias that have really large frontal openings, such as with the Stillen or WingsWest fascias. The J-Spec '99 fascia also has a large opening, but it isn't quite as tall. You must make sure that the filters are not exposed to this ram air or it will cause turbulence that will cause the mass airflow sensor to produce a "shaky" signal to the ECU - this causes rapid shifting of the fuel mixture from lean to rich and will ultimately cause the engine to stumble, sometimes even stall out. If you stand in front of your car about 12 feet back and then squat down to look directly into the filter area, if you can see any of the filter element, you should baffle it. Any exposed filter element will be subjected to high-speed air that causes a ram effect leading to turbulence in the mass airflow sensor(s). The "turbulence" issue has been called that a bit incorrectly though. It isn't really turbulence that causes the issue - it is actually a buffeting effect that occurs in the filter - sortof like when an airplane wing stalls - it is actually more like karman vortexing. It only occurs when the filter is exposed to a high speed stream of air. This stream of air creates a high pressure region on the front side of the filter and consequently, a low pressure region on the backside. Because of its shape, you actually produce a karman vortex that disrupts the flow of air passing over the hotfilm element within the mass airflow sensor. By preventing a highspeed stream of air from contacting the filter element at all, you will eliminate this problem - hence, the low-cost suggestion to use flower pots. Regardless, we are working on a completely new intake system for the Z32 right now - we're done messing with the OE Z32 MAS and dual intakes.
Enthusiasts soon understand each other. --W. Irving.
Are you an enthusiast? If you are out to describe the truth, leave elegance to the
tailor.
Albert Einstein
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