Cylinder 4 cooling mod
- Thread starter enda
- Start date
Not a good upgrade by all accounts . All it does it take coolant from the top cross over pipe . Iv attached a link from Scooby net And a photo from a lad who knows what he’s talking about running a track Subaru for 20 years .
To be honest and it’s just my opinion but Some lad in the arse hole of no where added a little pipe and a t piece and diverted coolant around suddenly knows better that Subaru Engineers who spent millions in developing the best most efficient cooling system for the engine .
I know who I’m trusting .
4th Cilinder cooling mod - ScoobyNet.com - Subaru Enthusiast Forum
General Technical - 4th Cilinder cooling mod - Has anyone done it? Seems to be a trend in the US. https://www.youtube.com/watch?v=4RoPoqbzt9c To me seems a bit overpriced, wich completly turns me off trying to importo from the US to my country.
www.scoobynet.com
I know who I’m trusting .
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Keadeen
Well-known member
Reason why cylinder 4 may run hotter is to do with the way the fuel rail is set up from the factory (my mapper told me).
As the 4th injector is the last on the rail, under heavy load, or sudden hard acceleration it can run a bit leaner than intended (as injector 1-3 get fuel first and takes a second for the fuel pump to catch up) and hence run hotter.
He said proper fix for this, especially for a car which does regular track days etc, is replacing fuel rail system with two rails (one for each side) and two fuel pressure regulators (2 stock will do). For road going cars that don't get track use he just maps in a bit extra fuel on the 4th injector under heavy load or sudden acceleration to allow for it and that fixes it too.
He said is nothing to do with the cooling system (although, again for trackday use, etc he recommended upgrading the factory radiator as it isn't able to cool at WOT for any length of time and has a weak point in the form of the plastic header.
As the 4th injector is the last on the rail, under heavy load, or sudden hard acceleration it can run a bit leaner than intended (as injector 1-3 get fuel first and takes a second for the fuel pump to catch up) and hence run hotter.
He said proper fix for this, especially for a car which does regular track days etc, is replacing fuel rail system with two rails (one for each side) and two fuel pressure regulators (2 stock will do). For road going cars that don't get track use he just maps in a bit extra fuel on the 4th injector under heavy load or sudden acceleration to allow for it and that fixes it too.
He said is nothing to do with the cooling system (although, again for trackday use, etc he recommended upgrading the factory radiator as it isn't able to cool at WOT for any length of time and has a weak point in the form of the plastic header.
