been a while since i added an update about my skyline project so here goes….
Ive fitted a set of 370cc injectors today and changed my base map, goes like a beast now well worth the work. All in all the upgrade took 2 hours, heres a guide on how this is done just incase you want to do it.
I thought it about time to do a DIY for removing/replacing/upgrading injectors in a RB25 series engine. These photos were done my my Series 2 R33, but it should apply to most RB’s I expect
Contrary to some posts I’ve seen, there is NO need to crack open the intake plenum to get to your injectors You only need to remove the AAC assembly and throttle body (and possibly FMIC piping).
The entire process should take you ~2 hours depending on your confidence/skills.
1) Remove AAC assembly. There is a DIY thread (HERE) on this but in this case, you only need to remove the AAC from the manifold, not pull it apart. Remove 3 hoses from AAC (circled in red) and loosen 3 bolts that hole AAC onto the manifold. There is no need to remove the hose from underneath the AAC unless you intend on removing and cleaning it.
2) Remove 3 bolts from AAC assembly. One bolt is circled in blue in above pic, but the other two are hidden underneath. Swing AAC away to the side. If the AAC is dirty inside, I suggest cleaning it as per AAC cleaning thread above.
3) Remove metal intake pipe. Remove 2 bolts from pipe bracket and loosen BOV recirc pipe (RHS of pic). Undo clamps that connect intake pipe to the throttle body, including one small hose that connects directly above the throttle body. Move intake pipe away from throttle body assembly.
4) Remove 4 bolts that hold the throttle body on and remove three other hoses (circled in red)
5) Undo a multitude of hoses (red circles) and unbolt the two bolts circled in blue. If you have a FMIC kit, take this opportunity to remove the pipe that runs over the radiator fan. You won’t be able to get the injector rail out otherwise.
6) Undo 3 bolts holding the injector rail onto the manifold. You will be able to get to 2 of these with a ratchet, but one will need a spanner. BE CAREFUL – each bolt has a plastic spacer between the injector rail tab and manifold which can be easily dislodged and lost. Remove these and keep for when you are bolt the rail back on.
7) The injector rail will be able to be removed now. BE CAREFUL AGAIN – Each injector pintle is inserted into a rubber ring which can also be easily dislodged. DO NOT lose these. After the rail has been removed from the, reach in and unplug each injector (you kind of need nimble hands for this). Carefully remove injector rail by lifting and sliding out towards the front of the car.
For each injector, remove the two screws (with Philips head) from the injector cover and take off. These screws will more than likely be tight.
9) To remove the injector… If you don’t have an injector puller (which most of us don’t), the CAREFULLY insert a screwdriver wrapped in rag into the hole at the top of injector and lever it out of the rail.
10) To fit injectors into rail, put a small amount of grease on the o-ring and place injectors into rail and place cover on the top of it. Only use rubber grease as some industrial greases will eat rubber and that can lead to disaster. Don’t try to push injectors into rail, as the cover with push it into place as you tighten the screws.
11) Put rail back into engine bay, ensureing that rubber pintle surrounds are in place, plastic spacer rings for the rail bolts are in place, injector plugs are plugged in, all hoses and clamps are replaced and tightened.
