[longassname]

I've made a nasty little discovery you won't be too happy to hear. Anyone that was paying attention to the stage III development thread want to guess what's responsible for that lean out above peak power at 5600ish rpms? I'm about to get into doing the final software for stage III so I'll have exact #'s for you soon to verify this (I've made some guesses and interpolations here and there in the prototype software)...but it seems the factory mass air meter actually maxes out in a stock svx. The afr plots go north above 5600 rpms because the maf meter is maxed out.

Originally Posted by mbtoloczko

Chike,

I have that same fuel consumption vs cylinder pressure plot in my locker. :-) As far as I know, the 2.5 RS fpr is working fine. I haven't looked at the vacuum line though. I haven't touched the fuel pump in any way. I suppose its possible that the ram air is having some effect, but keep in mind that the ecu does not just blindly add fuel. It meters fuel based on the MAF sensor reading (among other readings), so if the ram air is somehow messing up airflow at high rpm, the MAF would see this, and the ecu would add less fuel accordingly.

I'm fairly convinced that the afr reading is representative of what the SVX ecu is programmed to do. The other EG33 afr readouts from dyno runs that I've seen (SVXRide, LAN) show the afr progressively richening as the rpms increase. And if I look at the afr readings from your dyno runs, I see the same basic trend too. The afr on your car does richen as the rpms increase, and at peak rpm, there is a slight lean out. My afr runs show the same thing, and so do LANs.

As deruvian said, a little more power may be possible with the 2.5RS fpr by leaning out the mixture a bit at higher rpm using an SAFC-II (or something like it).