GFB Mach 1 Blow-off Valve User Manual

Mach 1 Blow-off Valve

Installation Instructions

P.O. Box 1017 Riverwood NSW 2210

Ph: [phone] Fax: [phone]

Website: www.gfb.com.au Email: [e-mail]

Installation Instructions for GFB Mach 1 Blow-off Valve

Included in kit (unless ordered with fittings other than standard):

• Mach 1 BOV, fitted w/ 35mm base & 30mm recirc outlet

• 1 x screw-in trumpet

• 1 x o-ring

The Mach 1 comes complete with all the parts required to set
it up as either a vent-to-atmosphere or a plumb back blow-off
valve. It comes pre-assembled in the atmosphere venting
configuration, and to switch to plumb back, you only need to
swap the trumpet for the supplied plumb back outlet.

Select the mode of venting you wish to use, and then begin the
installation by locating and removing the factory blow-off
valve, taking note of the hoses that connect to it. If the fittings
on your GFB Mach 1 do not match the factory hoses, or a bolt­on flange is required, check the adaptor listing at the end of
these instructions.

For cars without a factory blow-off valve, a suitable location
must be found on the inlet piping between the turbo and the
throttle body (see diagram opposite), and a hose or pipe
attached onto which to mount the Mach 1. The standard base
fitting of the Mach 1 can be mounted in two ways. It can
either be clamped into rubber/silicone hose, or it can be pipe mounted directly onto the turbo piping. These methods are
described below:

1) Hose mounting: The standard base
fitting of the GFB Mach 1 will fit inside 32­36mm I.D. hose, and should be secured using a
hose clamp (not supplied). Make sure that the
supplied o-ring and grub screws are not used
for this application, and that the hose clamp
band is seated on the straight section of the
collar, rather than on the retaining bead.

For atmosphere venting configuration, plug the
factory recirc hose as shown using the plastic
plug supplied. If you choose the plumb back
configuration, connect the recirc hose to the
supplied plumb back outlet as shown.

2) Pipe mounting: For cars without an existing blow-off or diverter valve, weld
a short length of 1” O.D. pipe to a suitable location on the turbo piping as shown in the
schematic engine diagram above (and the pipe-mount configuration cut-away diagram
opposite). Also available from GFB are alloy and stainless steel weld-on adaptors to
suit different intercooler pipe materials.

If your car has a flange-mounted factory valve, GFB has a range of vehicle-specific
bolt-on flange adaptors - check the adaptor guide at the end of these instructions for
available types.

Insert the supplied o-ring into the internal groove in the base of your GFB valve as
shown, and partially thread the three grub screws into the tapped holes. Slide the valve
onto the 1” (25.4mm) O.D. pipe, making sure that the o-ring slides completely over the
end of the pipe, and then fasten the valve in place with the grub screws and lock nuts.

MAKE SURE TO MOUNT THE BOV IN A POSITION WHERE DIRT OR
WATER CANNOT FALL INTO THE VENTING OUTLET.

• 3 x M5 grub screws and nuts

• 1 x 30mm hose plug