Re: 4KTQ Conversion Questions

[Scott Mockry <scottmo@teleport.com>]

Huw,

>That's great, but will a CIS-E system, as on a contemporary n/a engine,
>feed one successfully?  Or gen-u-ine CIS-E3, like on the NF or NG?
>I just like the aluminum fuel distributor I guess. 
>Huw Powell

I wouldn't use the 5000S (CIS-E) air flow metering assembly, (Bosch 0 438
121 049) because as mentioned, it has a smaller diameter near the end of
its travel, and therefore isn't designed to handle/meter as much air as the
5000 Turbo unit (Bosch 0 438 121 053).

I don't know the fuel flow rates are for the CIS-E fuel distributor (Bosch
0 438 101 029), but in order to use this with the MC engine Mac11 ECU which
normally drives the CIS freq valve with a varying duty cycle, you would
need to design a circuit to convert the duty cycle to current in milliamps
to actuate the differential pressure regulator enrichment feature on the
CIS-E fuel distributor.

According to some literature I dug up, the fuel distributor from 

the ur-quattro/1986 5000TQ (Bosch 0 438 100 123) flows 99% of the fuel
(cm3/min) that

the following fuel distributors flow. 
1986-88 5000TQ (Bosch 0 438 100 147) 
1989-90 200T/Q (Bosch 0 438 100 153)

If your intention was to just use the CIS-E fuel distributor, air flow
meter, and NF non-turbo ignition system on the Turbo conversion. Many have
tried this approach, and many had engines that ran, but none ran very well
IMHO, and they all had problems. I get emails from people who years later,
are still trying to sort out these conversion projects.

The MC engine, Audi 5000TQ MAC11 ECU uses timing map values based on
manifold pressure (boost/vacuum) and engine RPM to get the best timing
value for best torque and really nice drive-ability.
 The knock sensor system will reduce timing as needed during knock events.

The later dual knock sensor MC engine with the Mac14 ECU, does this one
step better, for really good timing management, and increased torque
output. (The K24, higher compression etc. give the most improvement)

The CIS-E ignition system never expects the manifold pressure to be more
than 1.0 bar absolute, so its timing values will be way off under boost
conditions, and expecting the knock sensor system to compensate for the
knock developed during boost, is a poor way IMHO to run the engine.
Headgaskets don't like repeated detonation over long periods, neither does
the aluminum cylinder head, and the ring lands in the pistons.

HTH
Scott