[DeTomaso] efi horse power gain

[Kirby Schrader]

Jack,

I have no idea how each cylinder's vacuum pulse can cancel out each other. That
means one pulse would be negative (vacuum) and the other positive (pressure).
Something seriously wrong with that engine!
Logically, the vacuum from each cylinder should be sequentially
additive until the
plenum value reaches steady state at a given engine rpm.

Whatever the case theoretically, with individual vacuum tubes from each of
my throttle bodies attached to the central plenum, I do have a
manifold pressure.
The ECU uses this as in input and I see the values change as the rpm changes
when I monitor the engine functions. So it does work.

I suppose one could argue that it doesn't react fast enough instantaneously to
be a 'good' input to the ECU. That's why TPS can be another input. As with all
computer control systems, the more information, the better the control.
I am assuming that the algorithms and programming are 'correct' here!
;-)

As a side note, I only use the #2 cylinder throttle body as a vacuum
source for my Pantera
brake booster. I was told this was not possible and would never work as there
would not be enough vacuum. Darn it, it inexplicably works with no drama.

:-)

Later,
Kirby

On Tue, Aug 11, 2009 at 1:43 AM, <JDeRyke at aol.com> wrote:
> In a message dated 8/10/09 6:51:47 PM, kenn_green at yahoo.com writes:
>
>> By pulses I just meant when an individual intake opened, but connecting
>> all the runners to a common chamber sounds like that issues is addressed
>>
> Ken, when I tried that for vacuum advance on IR-manifold Webers, I found
> the individual pressure pulses from one cylinder cancelled the next cylinder's
> vacuum pulse out so the average vacuum in an 8-tube vac manifold was zero.
> Maybe there's a way around this but I never found it. Good luck- J Deryke
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