ox sensor on sequential efi,high overlap cam....

[Greg Hermann]

>Group thoughts,
>
>Wide centers help Idle. Why??? Exhaust closes sooner??? Intake opens later???
>Narrow overlaps have more torque and higher efficiency (BM??) at peak. Seem to
>be peakier and "get UP on the Cam" more/sooner.
>
>Overlap causes EGR as well as intake charge in exhaust system. (intake and
>exhaust dilution).
>
>EFI is probably worse as most squirt fuel on the intake valve before it opens.
>Called "settle time" by Edelbrock. (more time to evaporate). That means the
>richest mixture is sucked in (thru) first.
>
>Exhaust tuning (pulses) suck the cylinder dry at some RPMs and block the
>exit at
>others. Turbo motors don't care. Cam duration and centers (overlap) can really
>hose up a system or make it purr like a kitten.
>
>Assuming we can measure the AFR with our O2 sensor (or EGOR) and tune to
>14.7 or
>12.5 or xxx, it still will not tell us how the motor is running. We still need
>to adjust each combination,,,, say to highest vacuum or whatever,,, so the it
>runs good (and does not polute). We still need to tune.
>
>Maybe we just set the idle speed above the problem areas for those of us with
>too much cam...( like too short shorts ) a lot is good, more is better and too
>much is just right.
>
>starting to ramble    sorry  Tom

Yo Tom--you are just arguing in favor of air boosted injectors, that's all!!

Regards, Greg