REFLECTOR: Fuel Flow for Performance Engines IO-550

[LAURA WALKER]

My Performance Engines IO-550 seems to run very lean, both at idle and at ground run-up. So lean, that if I shut down the Plasma ignition, it won't idle at all on just the magneto. I also get no rpm rise on mixture cutoff, and it hesitates to come off idle or low power. By accident, I once started it with low fuel pump boost on, and it ran much better, even idling on the magneto side alone. 

I think I have two problems: one, my tuned exhaust is scavenging the cylinders too well and the mixture needs to be richened to make up for it. And two, I need to make sure the fuel flow pressures are correct for my horsepower level.

Back when Ron Monson would talk to me, he figured I would be getting an additional 30-30HP from the addition of the tuned exhaust/headers which should total just around 400 HP.  The only fuel flow and pressure charts that came with my engine are from TCM's 310HP IO-550. My calculations say that I should be looking at 25% more fuel flow at full throttle or roughly 32-34 GPH. 

Anybody out there with the PE IO-550 experienced this, and if so, what are your fuel flow numbers?

Bill Walker