Throttle Body Upgrade


The throttle body is the part of the engine that lets air in.  It is composed of 2 flaps (often called "butterflies"), which open and close accordingly with how far the gas pedal is pressed.  A larger throttle body will allow more air into the engine, thereby improving the performance - both throttle response and horsepower.  This upgrade should only be done after you've upgraded the exhaust system.  The Fox's stock exhaust is so restrictive that the increased airflow from a larger throttle body will make the engine run worse when compared with the stock one.
Is your Fox upgradeable? Two approaches
Easy:  find a 1991-1993 VW Fox in a junk yard and get the intake manifold and throttle body.  They are a direct bolt-on for 1987-1990 Foxes, and include a blank spot to mount the cold-start enrichment injector, aka the "5th" injector.  The only thing you will have to do, is cap one vacuum fitting which is unused by CIS and CIS-E.
Difficult:  read below.  This should only be attempted if you have exhausted every possible resource and cannot find a 1991-1993 VW Fox to loot parts from.

Before you begin the difficult approach
This is a rather extensive modification, so don't try to perform it yourself if you don't have the experience with porting metal.  I do not suggesting going this route unless you absolutely cannot find a Digifant Fox intake manifold and throttle body.

Also, do not be fooled by the adapter plates that some tuners sell.  While the throttle body itself may be larger, if the air still gets into the intake manifold through the same sized opening, you'll gain nothing.

Where do you find the throttlebody? How to do it?
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