Timing control - manual vs. automatic

mark1

New member
Apr 19, 2009
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I've been going into paralysis by analysis mode looking at the various options for fuel injection plus timing control.

My question - does the automatic timing control on the Howell TBI system know to advance the timing as altitude increases, or is the adjustment based
on operating parameters that are the same at sea level or 10,000 feet - or maybe affected by vacuum (which will drop at altitude)?

Same for the timing control for the FiTech 600hp system. I don't see where there is any knock sensor on the system, so I have my doubts (fears) about
setting it up - at least without a standalone knock sensor.

And the other option is to install a "fuel only" system (Howell or FiTech), and use an adjustable timing control that would work on my existing HEI
distributor (there are a few MSD systems out there that should work, with a 0-15° timing adjustment knob). I'd also want to install a standalone
knock sensor if I went this way, but I like the idea of being able to twiddle my timing depending on load, altitude, and gas quality. Seems like this
might provide the option for a bit better performance in a given situation, unless one or both of the automatic timing control systems are
sophisticated enough to always be looking for the sweet spot in timing advance, while avoiding detonation at all times.
--
Mark Hickey
Mesa, AZ
1978 Royale Center Kitchen
 
> I've been going into paralysis by analysis mode looking at the various options for fuel injection plus timing control.
>
> My question - does the automatic timing control on the Howell TBI system know to advance the timing as altitude increases, or is the adjustment
> based on operating parameters that are the same at sea level or 10,000 feet - or maybe affected by vacuum (which will drop at altitude)?
>
> Same for the timing control for the FiTech 600hp system. I don't see where there is any knock sensor on the system, so I have my doubts (fears)
> about setting it up - at least without a standalone knock sensor.
>
> And the other option is to install a "fuel only" system (Howell or FiTech), and use an adjustable timing control that would work on my existing
> HEI distributor (there are a few MSD systems out there that should work, with a 0-15° timing adjustment knob). I'd also want to install a
> standalone knock sensor if I went this way, but I like the idea of being able to twiddle my timing depending on load, altitude, and gas quality.
> Seems like this might provide the option for a bit better performance in a given situation, unless one or both of the automatic timing control
> systems are sophisticated enough to always be looking for the sweet spot in timing advance, while avoiding detonation at all times.

Mark, you might find the efi group interesting.
https://groups.google.com/forum/#!forum/gmcmh-efi
Howell/EBL use manifold absolute pressure not vacuum so altitude makes little difference.
As far as twiddling timing that's available and a whole lot of other stuff, EFI is a tweakers paradise.
--
Wally Anderson
1975 Glenbrook
Megasquirt 455 port injection science project
Omaha Nebraska
Bob Stone hydroBOOOOST
Greater Midwest Classics
GMCES
http://wallyandsue.blogspot.com/