Hi gents, I'll have a new 406 up and running by the end of next month. I will be dynoing with an 850 carb. I'm thinking of giving either the FAST self learning EFI or the Holley self learning EFI a shot. The combo will make almost 600HP at 6600 RPM

I'm a little concerned about how the engine will idle with a large Hyd. Roller cam with specs of 258 / 263 at .050" on a 108LC. 640" / .640" on lift.

Anyone have any experience with a combo like this on one of the newer "Self Learning" EFI throttle body systems?

Thanks for your input:)

Pat

Just a data point here, but I emailed back and forth with FAST last week regarding their system potentially on my engine: 496, 655hp, with a bit (8 degrees or so) smaller cam than yours also on a 108ICL. My engine pulls about 7-8" of vacuum at idle, which they considered too low for using their EZ-EFI systems and said I'd be much better off with the XFI system. Seems XFI also has the self learning, but you have more flexibility within that system versus the EZ's to manipulate the idle characteristics on low vacuum engines.

I also emailed Doug F. here about Holley's Avenger system and he mentioned similarly that the vacuum was towards the low side for the system, but that it could be accommodated by plugging in a laptop and manipulating the idle characteristics manually.

If autotuning wont work work very well at low vacuum when at idle, couldnt you use the autotuning function at all other rev/tps points and then manually tune the idle by adjusting teh AIC motor, timing advance and fueling?

peace
Hog

If autotuning wont work work very well at low vacuum when at idle, couldnt you use the autotuning function at all other rev/tps points and then manually tune the idle by adjusting teh AIC motor, timing advance and fueling?

peace
Hog

You certainly can, you just need a system that is laptop programmable.

All of the auto-tuning options rely on the O2 sensor for feedback on what is happening in the system. Where you get into trouble is when you have too much cam overlap and a lot of mixture mixing at lower RPMs. This "contaminates" the exhaust flow leading to an incorrect reading from the O2 sensor.

Thus you need to manually tune in this operational regime on these combinations.

Yes at higher RPMs or conditions that reduce the exhaust contamination sufficiently the auto-tune will still work.

My 406 runs maybe 6" of vacuum with the EZ EFI Dual Quad. The idle is sent at 1000 rpm and it idles ok, not as good as my 383 that pulls 14 inches of vacuum but its ok considering. It does run better with the dual quad tunnel ram system than the single throttle body/Vic jr. I`d say you`re borderline with the EZ EFI. You can fine tune it but not to the extent of the XFI or a programmable system.