5th injector

[paddy138]

heard of this a few times, i know how stand alone injectors work, but what way does a 5th injector work, and were is it fitted

[Timmy]

i think its for turbos the cool them doen during high boot or its for aint lag, i think i could be wrong

[paddy138]

yeah it could be for antilag. isnt anti-lag controlled through the ecu tough

[Adam]

Its to supply extra fuel, for a boosted engine.
With a "proper" ecu you just map it so the 4 injectors supply the right amount of fuel.

Usually there controlled with a standardalone system, just to fire the 5th injector. Its a bit of a "bodgy" method imo.

Anti lag is a completely different thing, igniting a mixture with a exhaust valve(s) open to keep the turbine spinning etc.

[Stuart]

its a proper gippo way of sorting extra fuel.

[Will F]

Very popular in the early 90's when mappable management was a dreamlol

[Mike]

its still very popular on the Ford scene, what with ERST & FRST using it.

If you want boost, and a trick fuel system, use an 8 injector setup (pectel P8 system) like RS500 Sierra's :thumb:

[Stuart]

lol and look at about ?8k to get it running :D

[Mike]

lol and look at about ?8k to get it running :D

:thumb: dont you just know it lol lol

[vallanc3]

iirc the scooby type ra had a 5th injector

[paddy138]

seen the 8 injector set-up on you tube. it was on a vtec engine. was running on tbs with the extra 4 injectors placed before the tbs. was class.

[Welsh Dan]

If you're thinking about the same vid as I am, that was just remote injectors. The four you saw were the only 4.

[paddy138]

you could be right there

[paddy138]

:thumb:

[Adam]

its still very popular on the Ford scene, what with ERST & FRST using it.

Thats because the old Ford engines used a ****e fuel system :thumb: lol

[Timmy]

8 injectors on tb wil with you 10 or so more bhp.

[Philsutton]

Using 4 injectors that are matched correctly would be a hell of a lot cheaper and do the job. 5th injector is a seriously pikey way of doing it.

On a different note while cutting up a nova GTE engine loom for plugs for my corsas new loom I found to my horror that there are two wires going to all four injectors. One is an earth an the other a switch live, this bascially means that all the injectors fire at the same time. Take it vauxhall didnt care about fuel consumption then. Just thought Id share how crap they are lol.

[Stuart]

batch firing isnt a bad thing... it keeps cost down on the ECU

[Adam]

All 8v/engines without a cam sensor or crank & hall sensor are batched fired.
No real gain in independent firing afaik.

[Stuart]

can get more accurate transient fuelling with sequential. Ie when load/conditions change between the 1342 cycle etc.

[Philsutton]

i know but it just seems a waste of fuel, i get the idea that there are only three transistors an two 10k ohm resistors on the parts list for a GTE ecu lol. Saying that my megasquirt ecu is the same except its sends to signal lives ot to the injectors.