Installation, Setting up the ex50, Gfb ex50 wastegate – GFB EX50 50mm External Wastegate (part 7001) User Manual
Page 2: Weld-on fittings

GFB EX50 Wastegate
Packing list:
•
Assembled EX50 50mm wastegate, fitted with:
o
1 x 13psi spring (60mm O.D.)
o
2 x V-band clamps
o
1 x outlet weld-on flange (part # 7041)
o
1 x inlet weld-on flange (part # 7051)
o
Valve seat
 
Included in box: 
•
2 x banjo hose connectors & 1/8” BSP bolts
Installation
 
Install the boost nipples using a 5mm hex key, making sure that the head of 
the banjo bolt sits into the large tapered seat on the banjo as shown. Position 
the nipples in the best orientation for the installation. The thread is 1/8” 
BSP, which is a commonly available thread should you wish to use a 
different type of hose fitting. 
 
Weld-on fittings:
Already fitted to the EX50 you will find two
stainless steel fittings, which need to be welded onto your turbo exhaust 
manifold and exhaust system, onto which the EX50 is mounted using the 
supplied v-band clamps. The inlet and outlet weld-on fittings are both 
different, having been designed for the pipe that is most suitable for each 
purpose. 
 
The inlet fitting, which is welded to the exhaust manifold and supports the weight of the wastegate, is best suited to 1.5” 
(48mm) nominal bore Schedule 10 or 40 pipe – a commonly available heavy-walled pipe. The outlet fitting is designed 
to accept 2” (50mm) O.D. thin-walled pipe, which is commonly used for exhaust systems and screamer pipes. Of 
course, it is possible to use different size and wall-thickness pipes than those recommended, provided a suitable weld 
can be achieved. The weld-on fittings are available separately from GFB if required. 
 
The inlet fitting should be welded to the exhaust 
manifold after all the exhaust runners have 
merged, and in a position that promotes smooth 
flow to the wastegate – fast-moving exhaust gas 
is reluctant to make sharp turns, which 
significantly reduces the flow potential through 
the wastegate. The diagram opposite shows a 
suggested installation location. 
 
On any street-driven car, the wastegate outlet 
MUST be connected to the vehicle’s exhaust 
system (before any catalytic converters and 
mufflers), and should be done in a way that 
allows the gases to merge smoothly. On race 
cars where regulations allow, the outlet can be 
routed out of the engine bay to atmosphere. 
Setting up the EX50
 
Use the following guide to help set up your EX50. You should determine the minimum and maximum boost pressure 
that you want to run (if you are not planning to vary the boost, then the minimum and maximum are the same), and your 
control method. 
 
Care should be taken when selecting boost pressures, and it is always best initially to err on the conservative side, until 
the engine can be run on a dynamometer to ensure safety. Always consult an expert when making boost changes, and it 
is recommended that the car be checked on a dyno, as high boost and/or lean air/fuel mixtures can cause engine damage 
or worse, total failure. 
 
