QLCC History

[quk@isham-research.demon.co.uk (Phil Payne)]

In message <350878CC.157E@teleport.com> "Scott Mo." writes:

> The important thing to note, is that this information was freely spread
> between 5-6 people who were investigating how the MAC11 ECU worked and
> had the hardware or software knowledge to futher this investigation.

All very well, but it doesn't explain how useful the QLCC has been to us over 
here in Europe.
 
The MB engine fitted to the 1988/9 ur-quattro is essentially a hybrid of the 
MC-1 and MC-2.  Audi didn't build very many, and documented the engine 
management system _very_ poorly indeed.  I started into this business not from 
a point of wanting things to go better - but from wanting to know how to tell 
when they weren't going as well as they should.
 
Scott Mockry said one day that he might be able to help - if he could see the 
MAC12D's code.  I went down to the local scrappers, picked up a MAC12D (perhaps 
the only spare in the country at the time) for $300 and mailed it off to Scott.

Out of the goodness of his heart and pure charity, Scott took the ROM chip out, 
put in a socket, dumped the ROM, burnt an EPROM, and sent the lot back.  Some 
little while later, an email of the disassembled source code arrived.
 
The MAC12D is nothing more than a MAC11 with the emission controls code fairly 
crudely removed and a few values changed for the ur-quattro implementation.
 
At present, our side of the project is stalled because:
 
a) My car has been in the bodyshop for 8 weeks and I can't experiment and
 
b) I don't have a portable and accurate a/f meter.

We have, though, learned a great deal from Scott's and Orin's input over here.  
We have managed to explain very convincingly why MB engines are very hard to 
tweak with satisfactory results.  Some of the experts (e.g., Martin at BR 
Motorsport) already knew this from practical experience, and we've managed to 
account for the phenomena they observed.  The timing and boost maps explain 
some performance flat spots (one especially) that _should_ prove fairly easy to 
fix.  We have yet to crack the fuel frequency valve, but we're making progress.

If it hadn't been for the QLCC, I would _never_ (in a month of Sundays) have 
worked out how the MB's fuel injection system works.  I've been sharing the 
knowledge at club meetings, carrying fuel pressure meters and Scott's 
wonderful WGFV test light.  Without the QLCC, a whole raft of UK MB owners 
(John Scott, Tony Hill, me, Terry Gee) would still be driving round with sick 
cars.

-- 
 Phil Payne
 UK Audi [ur-]quattro Owners Club