[urq] Re: urq Digest, Vol 6, Issue 6

[Ned Ritchie]

Uh, let's think this through a little more. . .

-- Higher compression ratio means more prone detonation.

-- Higher boost also means more prone to detonation.

-- The higher the boost the more timing retard needed from the computer.

-- Tricking the computer to think boost is less leaves the timing
relatively advanced.

So for MAC 02 engine management to work you would not bleed pressure you
would add pressure some how to make sure the timing would be correctly
retarded.

Bleeding pressure would only allow more for a higher boost level before
fuel pump shut down.

You would need a modified lookup table for the computer to reference.

The situation is even worse when one uses a later MC engine with even
higher compression ratio.  In fact it never works well to transplant
that engine with a MAC 02 computer.

Ned Ritchie

-----Original Message-----
From: urq-bounces at audifans.com [mailto:urq-bounces at audifans.com] On
Behalf Of Justin
Sent: Wednesday, April 07, 2004 8:19 AM
To: urq at audifans.com
Subject: Re: [urq] Re: urq Digest, Vol 6, Issue 6

Yes, it is important to keep in mind that the MC and the WR/WX have
different compression ratio's....so there would need to be a modified
boost
sensor or bleed valve somewhere in order for the managment conversion to
work....
Justin
----- Original Message -----
From: "Ned Ritchie" <Q at IntendedAcceleration.com>
To: "'n mko j nm'" <chapman10 at juno.com>; <urq at audifans.com>
Sent: Tuesday, April 06, 2004 11:27 PM
Subject: RE: [urq] Re: urq Digest, Vol 6, Issue 6


> The compression ratio of the MC will in SOME cases, NOT ALL, be too
high
> for the MAC 02 computer to handle.  The timing of the MAC 02 is a
little
> more advanced so more prone to knocking.  This especially happens when
> you use higher than stock boost.
>
> And of course the opposite will happen if you use a MC computer with
the
> urQ engine.
>
> If I recall that even though the degrees before TDC for the reference
> pin is different so is the location of the sensor relative to the TDC
> point.  So this may be a moot point.  Check this out for yourselves.
>
> Ned
>
> -----Original Message-----
> From: urq-bounces at audifans.com [mailto:urq-bounces at audifans.com] On
> Behalf Of n mko j nm
> Sent: Tuesday, April 06, 2004 7:13 PM
> To: urq at audifans.com
> Subject: [urq] Re: urq Digest, Vol 6, Issue 6
>
> >Hi Frank,
>
>    If you're still running a MAC02, then you probably have a similar
> setup to mine, which I'm told was the quite common way to replace a
> blown
> urq motor with an MC back in the early to mid 90's. The PO had an MC
> installed in Southern Cal,after overheating the motor and the shop
> retained the MAC02 to avoid having to do the myriad wiring changes.
> Going
> that route demands that you reuse the stock urq flywheel and
distributor
> as well as the original fuel system and turbo,along with reusing the
> intake and oil filter block assembly. It's not a bad trade you get the
> hydraulics, higher compression,added displacement; but lose the knock
> sensor and water cooled turbo. The PO sold me the car because he
> purchased an 84 urq that was chipped with the stock WX. According to
> him,
> mine without a chip felt quite a bit faster than his 84 did, so I'm
> inclined to think that even with a few full MC losses, if that's what
> you
> have in there you're in good shape, Drive the hell out of it. Hope
this
> helped you a little. Cheers.
>
> Bill Chapman
> 83 Gobi, gotta love it
>
>
> >
> > Say.. Messing around with my urq, and leaking ECU hoses, leaking
> > fuel lines,
> > and  asorted 'mystery wiring' got me to thinking:
> >
> > How can I tell what "mystery motor" is in my urq?
> >
> > I'm thinking it's not the (original?) motor, as I think this one has
> > hydraulic lifters (The lifter noise increases, when the oil level
> > gets low).
> > Turbo is also water cooled.
> >
> > Can't read the motor number, as the 'flat area' where the numbers
> > are is too
> > heavily rusted.
> >
> > My concern is that if a MC motor made it into the car, did or did
> > not the
> > original flywheel get kept?
> >
> > It has the 'stock' ecu, but who knows what flywheel?
> >
> > If the 'wrong' flywheel is fitted, I'm assuming that the timing will
> > be off
> > by a constant offset (Equal to the offset of the 'pin'?).
> >
> > That should be easily enough figured out from checking against the
> > timing
> > information found in the IST or Bently Manuals, right?
> >
> > Does the above make sense, or am I way out to lunch?
> >
> > Regards,
> >
> >  -Frank de Kat-
>
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