This header was designed for the 98 spec DC2/DB8 ITR but with some fabrication will fit a DA and EF chassis. This is not a straight bolt-on job, some patience is required.

Oxgygen sensor setup: On non-OBD setups, 2 oxygen sensors are utilised on the stock exhaust manifold. The header has to be modified to accommodate this. Mark the positions on primaries 3 & 4 and drill holes into each primary and weld o2 sensor bungs on. The positions of bungs have to emulate the stock exhaust manifold, note the height and angle. Make sure there is enough clearance between the engine block and o2 sensors. Plug up the original o2 sensor hole (located at the collector) with a bolt.

Alternatively you could try using a 3 or 4 wire o2 sensor and place it in the original position. This would require splicing into the existing o2 sensor wires. Do not use a single wire o2 sensor for this method as it is too far down the exhaust system to work effectively. It will cause the car to hesitate and feel under powered at partial throttle. Click here and here to read more on closed loop/non-OBD setups.

Cross-member fabrication: By nature of the 4-1 design, the ITR header will not clear the DA and EF cross-member. Fabrication is required.

Removing the cross-member:

- remove both front wheels
- undo the shock fork bolt on both sides
- remove the bolts on the radius rods (2 bolts each side)
- there are 4 bolts that hold the cross-member on each side underneath the car, remove those and carefully slide the cross member out

Notch the centre portion of the cross member like the pictures below.

There are outlets that sell aftermarket cross-embers for the DA and EF chassis which allow clearance of 4-1 headers. Apart from giving clearance, they also minimize wheel hop and aid the car in handling to a certain extent.
- z10
- place racing
- jim fab

Bolt the header and cross-member back on. Don't forget the exhaust manifold gasket! Reset the ECU and check for exhaust leaks.

After a few months with this setup, I noticed the header rubbing slightly against the oil pan. With caution, I knocked the oil pan back to give it approximately 5mm clearance between the header. Perform with extreme care as you don't want to make large dents which may have a detrimental affect on oil flow to the pickup.

Ground clearance is also another issue to be aware of. Try to avoid large road debris.

Happy hybriding!