Turbocharging kjet 3

[rob hod]

    Hi Alan, all

    I'll have a stab at straightening this out for you. I'm no expert
myself, but here are some fundamentals. I won't refer to OXS/catalyst cisIII
set ups where the frequency valve gets involved in further fuelling mods via
CP adjustment.

    Fuel supply to the injectors (except CSV) is totally at the control of
the metering plunger in the fuel distributor.
    The air flap is attached to a long lever which controls the position of
the metering plunger. So in basic terms the fuel supply
 is matched to the mass air flow. Again talking in basic terms you can
forget all about boost pressures and so on, as the more air the engine
consumes, the more fuel will be supplied. The obvious constraint is when the
air plate maxes out at the end of its range of movement, which is what I
beleive Javad and Co. are referring to as the limit of CIS fuelling.

    As far as turbo apps are concerned, all that talk about manifold
pressure occurs down stream of the air flap and is therefore not directly
relevant to discusssions about fueling.

    As far as the warm up regulator goes, this is purely concerned with
enriching the mixture when below working temp. How does it do this?, well it
lowers the control pressure, which is the force opposing the movement of
the air flap, which means that for a given air flow more fuel is supplied
i.e. the mixture is richened.  How does it lower control pressure? It does
this by means of a valve which is shut at normal working temp, but which
opens progressively below that temp and bleeds fuel from the CP circuit back
via the fuel dist. to the fuel return line. (Since the CP circuit has a
calibrated supply this bleeding lowers the CP) Yes  it does have a
connection to the manifold, but I think (not sure ) that this is to do with
controlling overenrichment under sudden acceleration conditions ( under
which the CIS system by nature already tends to enrichen due to inertia
effects of sudden air plate movements).

    So to sum up, forget about the warm up reg as an a way of controlling
fuel supply, It is a simple but effective enrichment device, but due to a
bi-mettalic spring which holds the bleed valve closed once warm, it stops
doing anything once the engine has warmed up

    Also in general forget about turbo boost as far as mixture adjustment is
concerned. The basics of the system, - air flap, metering plunger and fuel
dist act to ensure that a roughly suitable mix is supplied. Once the air
plate has maxed out though, you will go lean, over to the turbo guys as to
where that happens.....


    HTH


rob
----- Original Message ----- > Message: 4
> From: Alan Pritchard <apritchard at seaeye.com>
> To: "'JShadzi at aol.com'" <JShadzi at aol.com>
> Cc: "Quattro List (E-mail)" <quattro at audifans.com>
> Subject: RE: Turbocharging kjet 3
> Date: Mon, 30 Sep 2002 15:58:57 +0100
>
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> Thanks javad, but I thought that if manifold pressure rises the
differential
> between fuel pressure and manifold pressure will be less, therefore less
> fuel will be delivered. So how does cis 3 compensate?
> And does anyone know how to put outlook 2000 into plain text?
>
> Best Regards,
> Alan Pritchard
> Network Administrator
>
>
>
> Tel.  01329 289000
> Fax. 01329 289001
> www.seaeye.com
>
> -----Original Message-----
> From: JShadzi at aol.com [mailto:JShadzi at aol.com]
> Sent: Monday, September 30, 2002 3:39 PM
> To: apritchard at seaeye.com; quattro at audifans.com
> Subject: Re: Turbocharging kjet 3
>
> Alan, the CIS3 system can easily supply fuel to past 10psi, it starts
> leaning out around 12psi IME.  No need to richen the CO or anything like
> that, just set it to 0mA, you may have to retard the initial timing
> somewhat.  There is not any problem with the pressure differential across
> the injectors and manifold pressure that I"m aware of.
>
> Javad
>
> In a message dated 9/30/2002 7:27:24 AM Pacific Daylight Time,
> apritchard at seaeye.com writes:
>
>
>
>
> Hi guys, ive slowly but surely been gathering parts and I recently noticed
> something.
> On my 84 cgt there was a warm up regulator, this also had a hose which
> connected to the im, this, so I was told, would suitably enrichen the
> mixture under boost.
> However on my 90q there is no such device. So on draw through the cis unit
> would measure the air, but not allow for the heating of the air and the
> additional pressure on the injector tips so the mixture would be out, this
> would be compensated for by the o2 sensor, but on WOT were there may be as
> much as 10 psi (realistic) on the manifold side of the injectors the
mixture
> would really lean out.  Therefore 2 options would be to overrichen the
idle
> mixture (not the best option) or fit a pressure controlled fuel regulator,
a
> la the one of the cgt, so is this possible or is there an easier way???
> I do want to got to efi but not immediately, after all there is only so
much
> I can do on 9.6:1 compression (kv/ng hybrid), it should be possible as I
> have seen 12:1 hondas running 5-9 psi.
> thanks
>
> Best Regards,
> Alan Pritchard
> Network Administrator
>
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