EvilBevel

Jim, you don't need an AFR with the Unichip setup ... you adjust the fuelling (and ignition) maps in the Unichip.

The Unichip rides on top of the standard ECU. You use it to "correct" the values the OEM ECU is either seeing or sending out.

What Mark was saying is that as long as your fuelling map is driven by MAF/RPM instead of MAP/RPM, you don't necessarily have to enrich mixtures when you improve volumetric efficiency.

With a MAP/RPM load site driven ECU (like the Link), you have to adjust your fuelling, because - at the same boost pressure - you will use more air (generally) when fitting breathing mods. With a MAF dependant setup, the extra air is accounted for, and therefor injector duty cycle will be calculated correctly. The standard ECU on a MY99/00 reacts a bit on the "squirty" side when seeing higher MAF values, and tends to overfuel more & more.

In his case - as amazing as it may sound - he needed to seriously "lean out" the mixture over the whole map in the Unichip in comparison to before the manifold was fitted.

Mark does use an uprated "high flow" fuel pump though, and the effect that has on a MY99/00 is pretty amazing.

Theo

EMS

Thanks Theo (EvilBevel),

I have nothing to add at your comment.

Mark Verhoeven.