closed deck block and 5th injector
 

I hve seen ppl using this term 'it has the usual closed deck block and 5th injector'
Can some 1 explain plz

Most Subaru have 4 fuel injectors (1 per cylinder) but some type ra's and possibly type r's had a fifth injector mounted centrally on the inlet manifold, rumour was it was for homologation purposes

Yes, but only version 1 & 2 type Ra's/STi type Ra.
There are not used on the road cars but they are plumbed in for fuel and connected to the electrical system.

Ah i see, Would i be right in thinking the 5th injector is to keep the fuel rail full of Petrol, under heavy use..?

Nothing to do with the fuel rail pressure, it sits in the inlet plenum.

I suspect it would have been masquraded as a cold start injector on the road cars when it really did nothing and was there for homologation purposes for the WI on the rally car.

Not an important extra to look out for when buying a Scooby thn

???????? must b just me but wtf is homologation purposes ???????????

for certain races series you (the manufacturer) will need to have made a specified number of road going versions of a race car, these road versions of the race car must have the same basic layout to make them suitable/eligible for the specified race series by having the same basic components, EG by having a 5th injector for the road car (which did nothing) you could have a 5th injector on the race car, which injected more fuel etc etc

I heard rumours that they used it for water injection on the rally cars.

On my rally car the 5th injector is mounted on top of the Inlet manifold and is there to add extra an extra fuel / air mix before it all goes into the cylinders.... I hope that water isn't in it!!!!!!

:D
Rob