Clearance
Next up is the plenum, High Pressure fuel lines to the fuel rail & intake side loom. There is no clear part to go first so I spent some time checking clearances & positions of various items before anything is fixed:
Bonnet on to check head/side room, on the GT chassis there is plenty of room all around the intake side, the bonnet virtually sits flat on the top of the timing belt cover at the front of the engine though:
HP Fuel line layout
Space established, I need to decide on the lines from the swirl tank to the fuel rail. I have already decided (I think) to feed the OEM fuel pressure regulator at the front of the engine, and take the return from the rail at the rear via the cut down fuel rail tube.
Three options present themselves for routing the lines:
A. Take the line along the chassis tube and a gentle arc around the outside of the plenum: <- This
I like this option - looks neat, no tight turns and leaves the other side of the plenum for wiring
B. Still take the line along the chassis tube, but inside the plenum line up to the regulator:
Experience on RHOCar shows this option has been done before & known to be ok
C. Take the line across the top of the fuel rail and loop back to the regulator: <- Not this
Unlikely option - the loop just looks messy
The decision (between option A. & B.) will be based on any consensus from RHOCar & I may also ring GBS to check.
There seems to also be an issue with clutch cable routing - very tight under the plenum, will need checking before it is attached permanently.
Plenum prep
Before fitting I can do a couple of jobs on the plenum itself, fit my IAC Valve & fit the butterfly valve assembly. The IACV needs 3 holes, and needed to be in a location where I can get to the nuts on the back for assembly. I checked the location to make sure it would also miss the chassis tubes when installed.
Inside, lock nuts so should be little chance of losing them into the engine, and the second picture shows a glimpse of the trumpets on each intake:
Almost ready for fitting (needs the air temp sensor fitting too):
Update - later I opened up the main IACV air inlet hole on the plenum to be larger than pictured here and closer to the actual valve size, i.e. 16mm which lets the IACV have more control over the volume of air let in.