Re: Poor Man's ECU Fuel Enrichment

[DeWitt Harrison <de@aztek-eng.com>]

On Tue, 30 Dec 1997 06:45:29 +0000, Douglas Quebbeman wrote:
>[ ... ]
>Has anyone considered using the cold-start valve for WOT fuel
>enrichment? It seems like it would be pretty simple to do. The
>cold start valve delivers fuel at a fixed rate, and it's not metered
>by the fuel distributor, of course. [ ... ]

"Not metered" is the key phase.  This sort of full throttle
enrichment is, at best, a very crude way to avoid detonation
in "poorly" executed turbo designs. With this arrangement,
the mixture can only be correct at a single value of air
flow or WOT rpm. The mixture will be too rich until
that flow is reached and too lean beyond.  Some folks
on the list have figured out ways to work with the CIS
system to get higher _metered_ fuel delivery. This path
is not very well documented here so far. There may be
alternative methods to meter extra fuel such as an
external, aftermarket controllers to operate additional
injector(s). Get "Turbo" magazine for ideas. Buy
Corky Bell's "Maximum Boost" book for sound thinking.

DeWitt Harrison    de@aztek-eng.com
Boulder, CO
88 5kcstq