Turbosmart BLOW OFF VALVES - BMW Dual Port_Plumb Back Kompact Kit. BMW 135i, 335i, 535i and Z4 (N54 twin turbo 3.0L) – Kompact - Manual (Page 5)

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5
ADJUSTING YOUR BOV (DUAL PORT ONLY)
The aim of the adjustment on the Dual port is to make sure that the piston is hard closed at idle and that the piston closes fast enough
to minimise backfiring and not stall the engine.
Adjustment to the BOV is made by rotating the cap. To increase the spring force on the piston, rotate the cap clockwise in the direction
of hard as marked on the top of the cap. To decrease the spring force on the piston, rotate the cap anticlockwise in the direction of soft
as marked on the top of the cap - CAUTION - Do not rotate the cap beyond the O-Ring groove. If the cap is fully wound down and the
piston is still open at idle, remove the cap and install 2 shims to increase the force. Re install the cap and check that the piston is fully
closed at idle. Add more shims if required. Once it is confirmed that the piston is fully closed at idle, perform the following adjustment
procedure.

Start with the BOV cap at the maximum soft position (The indicator O-Ring should be completely covered by the edge of the cap)
 With the engine at idle the exhaust port should be closed off by the piston – the piston should be hard against the seat and not
floating or moving
 Free rev the engine and back off quickly, the engine should return to normal idle speed – if the engine drops below idle or stalls
increase the spring tension by one turn
 Repeat this process until the engine free revs and returns to normal idle speed
 Test drive the car and ensure that when decelerating or changing gears that the engine has minimal backfiring and no stalling. If
backfiring is excessive or stalling is noticed then check all connections made during the installation, otherwise increase the spring
tension
MAINTENANCE
Turbosmart recommends that the following maintenance procedure is carried out at six monthly intervals or at higher intervals if the
environment is very dusty or wet. Regular maintenance will ensure that your BOV is operating at its peak performance and will extend
the working life of the product.
 Remove the cap of the BOV by rotating in an anti-clockwise direction – CAUTION, the cap is under spring force, remove with
care!
 Carefully remove the piston and thoroughly clean the piston and the bore of the BOV
 Inspect the surface of the piston and the bore of the BOV for scoring or excessive wear, silver coloured marks on the bore are
an indication of excessive wear
 Check the Base O-ring and the Cap O-ring for any damage – replace if necessary
 Lubricate the bore and the piston with Uni-Glide™, hydraulic oil or sewing machine oil – DO NOT use grease or viscous oils
 Re-assemble the BOV in the reverse order
TROUBLE SHOOTING
The following points should be checked if you find that your engine is dipping below normal idle, stalling or if the BOV is functioning
poorly. Please note: the following checks will cure 99% of problems experienced with a BOV.
-
Check the vacuum hose for splits, cracks, loose connection, kinking or any obstruction – old or fatigued hose may collapse
under vacuum causing an obstruction.
- With the engine running remove the vacuum / boost hose from the nipple in the cap of the BOV, there should a loud hissing
sound. The engine should idle poorly, double check by covering the end of the hose with your finger – otherwise the hose is
blocked.
- Check to see if the BOV is blocked or contaminated with dirt or debris.
- Ensure that the vacuum / boost source is not shared and that the vacuum source is directly from the inlet manifold.
- Check the seal between the intercooler flange and the BOV. Make sure the supplied gasket is installed and the BOV Flange
is secured on the intercooler flange with the two factory bolts.
- Ensure the spring clamps are secured on silicon hoses and fittings.