How to give your Tdi's a performance boost - pictures

<span><span><span>The boost pin is inside this housing on top of the fuel pump. There are just four screws to be removed before carefully lifting the cover off.</span></span></span>

<span>Take care not to damage the rubber diaphragm, which is against the underside of the cover plate. More haste, less speed.</span>

<span>Remove the rubber diaphragm, but leave the spring in position for now. Lift the white plastic washer out and keep it safe for later.</span>

<span>The sliding pin and diaphragm come out as one unit. Swap the pin for the new boost pin (bottom of picture, with it’s modified profile).</span>

<span>As the new pin is fitted, use a marker to highlight this dot in the plate washer, and align it with the pin’s machined profile.</span>

<span>A mark is also made on the top of the plate washer so we know which way it faces when refitted back into the injection pump.</span>

<span>Grease is smeared on the working surface of the boost pin. The guide pin works against this surface (see mark on original pin in picture 4).</span>

<span>With the spring lifted out, the star wheel adjuster ring (which sets the spring’s pre-load) is reference marked in case it needs adjustment later.</span>

<span>The spring and diaphragm/pin assembly are refitted (note orientation), and the cap is screwed down ensuring the diaphragm is seated in the body recess without any nipping.</span>

Initial smoking was sorted by making careful adjustments and re-tests

After adjustments and five re-checks on the road, the smoke was reduced to a minimal puff at the start of acceleration.&nbsp;