GFB T9504 User Manual

Deceptor Pro II (part # T9504)

Installing and wiring the in-car volume controller

1) Test the unit before installation by connecting the Deceptor Pro II’s plug to the in-car controller. Connect the red

wire to the positive terminal of your car’s battery or a 12V source. Connect the black wire to the negative

terminal. Upon initial power-up, the unit will perform an open/close cycle before reverting to the position
indicated on the controller dial. By turning the dial and watching through one of the valve’s venting outlets, you
will see the inner sleeve move to open or close each of the venting ports alternately, which is how the venting
volume is adjusted.

2) Find a suitable location on or around the dashboard, steering column

or instrument binnacle for your in-car volume controller. Clean both
mating surfaces with Methylated Spirits or similar cleaner and secure
the controller using the supplied double-sided tape. Press hard and
hold the unit for about 30 seconds, and note that it takes up to 24
hours for the tape to develop a strong bond.

3) Using a multi-meter or voltmeter, find a suitable power wire that

reads 12V only when the ignition is turned on. Solder the end of the
volume controller positive (red) wire to the 12V source. It is possible
to use a wire tap or crimp instead, but soldering is the most reliable
joint. Make sure to insulate the joint properly.

4) Find a suitable bolt on the body/chassis and connect the unit’s ground (black) wire to it.

5) At this point you should plug the Deceptor Pro II back into the in-car

volume controller, and test its operation again to ensure the electrical
connections are good. Make sure the unit powers on and off with the
ignition.

6) Unplug the Deceptor Pro II and pass the controller’s extension lead

through the firewall into the engine bay. Often there is an existing
grommet that can be used for this purpose. In any case, it is
important to ensure that the lead is protected where it passes through
the firewall to prevent wear or damage.

Using the In-Car Controller

When powered up the volume dial rim will glow red, and will brighten for easy reading when you make an
adjustment, then automatically dim 3 seconds later to reduce unnecessary glare. The position of the dial is directly
proportional the venting bias - turning the dial fully anti-clockwise sets the valve to 100% recirc, fully clockwise
results in 100% atmosphere venting, and any proportion is possible between these limits.

The controller also features a program button on the rear of the casing. This can be used to limit the range of the
atmosphere-venting bias of the Deceptor Pro II. For example, if you prefer that the maximum atmosphere venting bias
is 50%, you can program the controller so that full travel on the dial gives you only 50% movement at the valve. This
is particularly useful on cars that through experimentation, find that full atmosphere venting does not agree with them.

To use this feature, set the dial in a position that you want as your maximum atmosphere-venting limit, then press and
hold the program button until the dial flashes. The unit will now record this position as the maximum atmosphere­venting limit. Now when you turn the dial fully clockwise, the Deceptor Pro II will only open as far as the point
which you have just set. For example, if you pushed the button with the dial set in the middle (50% atmosphere
venting), full travel of the dial will now move the valve from full recirc to 50% atmosphere-venting only.

To re-set the controller to allow the full range again, simply turn the dial fully clockwise and hold the button.

Valve Installation

The Deceptor Pro II (part # T9504) is designed as a direct replacement for the factory bypass
valve on Nissan 200SX/Silvia S14-S15 models with the SR20DET engine. It mounts onto the
lower half of the factory bypass valve so that it fits in the factory location. You MUST have the
factory bypass valve and associated hoses in order to fit this valve.

1) Unclamp the battery and remove it. This will

make access much easier, but before doing so
check that it will not affect any aftermarket
alarm, stereo or other electrical accessories.

2) Loosen the two hose clamps on the factory

valve shown opposite, and the hose clamp on
intercooler end of the BOV feed hose. Using a
10mm socket, undo the two mounting bolts
holding the factory valve to its bracket. The
second bolt is much easier to undo if the rubber
recirc hose is removed from the valve and bent
out of the way.

3) Remove the vacuum hose from the top of the

factory valve (this hose is a tight fit, try using a
flat screwdriver to push the hose off, rather than
pulling it).

4) Pull the plastic feed pipe off its fitting on the

intercooler pipe so that the factory valve and
plastic pipe can be removed as shown.

5) Remove the factory valve from the lower

elbow by undoing the 3 Phillips head screws
on the underside of the flange. Position the
Deceptor Pro II onto the elbow, ensuring that
the orange factory o-ring found between the
valve and elbow is used, and the locating pin
and matching hole on the BOV flange line up.

6) Rotate the Deceptor Pro II so that the recirc

outlet points in the same direction as it does on
the factory valve, then use the factory screws
to clamp it firmly to the flange.

7) Replace the assembly back into the factory

position in the reverse order of removal,
and double-check all hose clamps.

8) Now is the time to run the cable from the

control box to the Deceptor Pro II valve,
making sure to secure it along the way so it
cannot be damaged. Re-install the battery
and test the controller.

Spring Adjustment

Contrary to popular belief, the spring pre-load DOES NOT need to be adjusted to suit different
boost levels. The valve will stay shut under full throttle conditions regardless of boost pressure or
spring pre-load.

Rather, the spring pre-load affects how easily
the valve opens when you lift the throttle, and
how long it stays open when it vents. Adjusting
the spring is a simple matter of ensuring the
valve opens enough to release the air, but not
long enough to cause idling problems. The guide
below will walk you through the steps involved.

The screw in the centre of the head is the spring
adjuster (shown opposite). Use the supplied
5mm hex key for this screw.

The softest spring setting is achieved when the top of the adjustment screw is 3mm above the head
of the valve. Do not set the screw more than 3mm above the head.

 Set the spring to the softest setting, and set the venting bias (via the electronic controller) to

50% atmosphere venting so you can hear the valve vent during setup

 Start the car and let it warm up to normal operating temperature. Make sure the A/C is off
 Give the engine a good hard rev, and listen to the valve venting. It should blow off

immediately after closing the throttle, and should only be audible for a relatively short
duration. The harder you stab the throttle, the louder the valve will vent (note: it will only
open fully when driving, as the turbo does not generate significant boost until the engine is
under load).

 If the piston stays open too long and venting continues as the revs drop back to idle, the

engine will “stumble”, or the idle will be unstable. If this happens, wind the adjustment
screw in the “+” direction one turn at a time until the engine returns smoothly to idle after

revving

 For the final fine-tune, take the car for a drive. Watch the tacho as you pull up to a stop - if

the revs dip below idle and then rise again, tighten the spring another 1-2 turns

 If a loud flutter is heard when lifting off sharply after accelerating hard above 3500RPM,

wind the adjustment screw in the “-“ direction one turn at a time until the noise disappears.
Note that it is common to hear a slight fluttering at low RPM, particularly if you partially
spool the turbo and lift off slowly. This is a result of the different way in which this valve
operates compared to the factory unit, and is perfectly normal and not detrimental to the
turbo. However, there should be no flutter when lifting off from full boost above 3500RPM.

A video example of setting up the spring pre-load can be seen at:

http://www.youtube.com/watch?v=iqQR5WUF9lc

Maintenance

GFB blow-off valves are designed to be as maintenance-free as possible. In most cars the small
amount of crankcase and rocker-cover oil vapor that is directed into the intake system is enough to
keep the piston well lubricated. However, if you notice the sound of the valve changing over time
(e.g. slow response time, intermittent operation), or if you can see that the piston is not moving
smoothly, it may require a clean and re-lube.

Remove the Deceptor Pro II from the car entirely, then remove the four screws holding on the cap,
taking care as the spring will try to push the cap off as the last screw is removed. Remove the
spring and the brass piston, and wipe any grime from the inside of the valve and the piston with a
rag. Apply normal engine oil to the piston and the inside of the bore, and re-assemble.

Technical Support

If you experience any issues during installation or use of your GFB Deceptor Pro II that are not
answered in these instructions, please contact the GFB tech support team on [phone], or
email [e-mail].

This product is intended for racing use only, and it is the owner’s responsibility to be aware of the legalities of fitting this product in his
or her state/territory regarding noise, emissions and vehicle modifications.

GFB products are engineered for best performance, however incorrect use or modification of factory systems may cause damage to or
reduce the longevity of the engine/drive-train components.

GFB recommends that only qualified motor engineers fit this product. Warranty is for the period of one year from the date of
purchase and is limited only to the repair or replacement of GFB products provided they are used as intended and in accordance with
all appropriate warnings and limitations. No other warranty is expressed or implied.