Re: MAC01 and MAC02

[dlawson@ball.com (Dave Lawson)]

Mike,

     I don't have a problem with this at all and Ned provides a very good
     service for some people... but for others (like me, RDH, etc.) who 
would
     prefer to modify the ECU and/or the EPROM code themselves it would be
     great  information to have. To understand exactly how Audi detuned the 
North
     American cars by 40 horses would be VERY interesting. I know the 
engines
     themselves differ, but I think the biggest fundamental differences are 
in
     the operation of the MAC01 versus MAC02, probably the timing versus
     boost maps, over boost maps and the O2 sensor feedback?

I was going over an 82 euro ur-quattro the other day and got another
data point on US/euro car differences.  I didn't pull the ECU so I am
not sure what it has. I will check that some other day if I get the chance.

When you look at the underhood pictures of ur-quattros, the US and
euro cars are similar but not the same. An obvious difference is the
fuel system dampers are missing on the euro cars. And checking
the 82 car confirmed this and I also notice that the O2 freq valve is
absent. Checking the exhaust manifold, there is no O2 sensor, not
even a boss for it. So, the early euro cars run open loop on the fuel
system. This 82 has no cat. I also think the fuel distributors are
different, but didn't write down any part numbers.

More checking on the exhaust manifold revealed a metal pipe which
was tapped in forward of the turbo, which went rearward and was
used to actuate the wastegate. On the US ur-quattros, the wastegate
is actuated by boost pressure before the throttle body, not pressure
inside the exhaust manifold.

On the WR(euro) engines, the camshafts are different than the WX(US)
versions. The WR ones have more lift, not sure about duration.

Another difference I had never noticed before, was for the rear seat belts.
The euro car had no bolt attachments in the C pillars for the rear outward
seat belts. The back seat was filled with parts so I couldn't check for the
lap belts.

     p.s. I'm sure I saw a 4 door 4000 turbo quattro with flared wheel 
arches
     and 6" Ronals down at the local pub last night. Which years were they
     imported to Canada and would this still be called an ur-q?

You must have seen a home brew project. No such beast was ever
produced by the factory for mass consumption. Could it have been
from the garage of either Sprongle or Solaroli?
 -
Dave Lawson  dlawson@ball.com