Planning to completely de-cat my MY99 and was advised the mixture may need adjusting beyond the range the ECU can compensate for.

Has anyone had theirs checked after doing this? My Subaru dealer mentioned that all the piston melts he had dealt with, were from exhaust and filter mods.

MB

 

No adjustment is required. That is what the mass air flow meter is for so that the ECU knows how much air is flowing when you improve the volumetric efficiency with an exhaust. Arguably have a free flow exhaust is safer for your engine. A lot of people have this airflow meter fail with induction kits so you may want to reconsider if you were thinking of one.

My car's airflow is about 25% on top of standard on the original ECU and it fuels just fine - unbelievably rich like standard.

 

Thanks John,

Definately won't be going for an induction cone, I had one previously and made the car un-responsive. I have an ITG at the moment.

De-cat here I come! Incidentally, how would jou adjust it if it was out? I presume it would involve re-mapping?

MB

 

Remap with the original ECU, standalone Link or other ECUs, piggyback Unichip, or bolt on MAF modifiers such as HKS or Apexi AFR/AFC fuel computers.

The MY99 has 440cc injectors which I honestly believe you would struggle to max out on the standard turbo no matter what you did to the car otherwise. The standard turbo just cannot seem to flow enough mass of air for this to happen very easily.

Once the injectors max out then the car may get progressively leaner, depending on fuel pressure. You'd be making probably well over 40% power increase on standard by then and really know about it!