RDH's UrQ Page

What's an "UrQ", you may ask? Well, if you have to ask, you probably don't really want to know.

Quattro Line Drawing

An UrQ, short for Ur Quattro, or "The Original Quattro" (aka the Turbo Quattro Coupe, aka Coupe Quattro Turbo, and other such permutations) is the limited-production Rallye Group B Homologation car that Audi foisted on an unsuspecting public in the early '80s. (At least one wag has opined that "UrQ" -- pronounced "urk" -- is in fact the sound your wallet makes as your UrQ sucks all the money out of it. Caveat Emptor, Nolo Contendre, and all of those other funny furrin sayings.)

First imported into the U.S. in 1983 (Canada 1982?), this is the car that Audi used to introduce a viable production "High Performance All Wheel Drive" automobile into the world's automotive mainstream.

Building on the homologation base car, Audi virtually dominated the world's rally circuits for a number of years. From there, Audi went to Pikes Peak for the annual Hillclimb, and -- based on what is in essence a "family car" (and driven by a woman, Michelle Mouton, no less) -- proceded to blow away the dedicated purpose-built sprint cars that "owned" Pikes Peak, much to the chagrin of the odds-makers, and the delight of the crowds! Audi then went on to actually enter -- GASP! -- TransAm competition with yet another "overweight and underpowered" Audi Quattro, and proceded to thoroughly annihilate the rest of the field of Good Ole Murican Stockcars. TransAm's red-faced rednecks essentially outlawed the Quattro ("Well, if 500 pounds of lead in the trunk won't do it, stuffing a sock up your turbo will!), so Audi went home in a huff, with a suitcase full of trophies.

Here's a larger side view of an UrQ, and a cutaway view.

And here is my beast, at Elevation 14,110ft [154KB]. Yup, it actually clumb Pikes Peak. Wouldn't idle worth a damn when it got there (then again, I didn't fare much better), nor would it start afterwards, but being the experienced Audiist that I am, I parked facing downhill! Ha! Here's a more recent shot showing off the Beast's New Boots [141KB]. And finally, a shot of the interior, showing the Abt Instrument Cluster [117KB] as well as a few other mods you might pick out of the shadows.

Incidently, my UrQ has been sold.

Reference information (like what fuse is which) about the car is hard to find (What? you think the owner's manual tells you anything? You even have an owner's manual?), so in an effort to insinuate myself into the hearts and souls of UrQindred everywhere (as well as to try to use up my WEB page disk quota), I've included some helpful, or just randomly interesting, clickables:

Stock, the UrQ is a mixed blessing. It has the understated competence typical of a [properly maintained] Quattro -- the sort of competence that is so obviously right that you tend not to notice it until you get into almost any other car, and it's just not there. But, in U.S. trim, its performance (its "High Performance" nudge nudge) is, well, underwhelming.

There are a number of aftermarket "tuners" out there to help you spice up your UrQ's life, most notably Ned Ritchie of Intended Acceleration, and Total Audi Performance.

However, being a computer programmer of many years' experience, I balked at spending $800 (or thereabouts) to diddle a few bytes in the ROM. So I undertook to decode/reprogram my ECU ("Engine Control Unit" -- the "computer") myself. (If I knew then what I know now, I'd just have forked over the money and gotten on with my life...)

The first step was of course to secure a disassembler so I could take a look at the stock/factory programming. Looking around, I didn't see any handy Motorola m6800 disassemblers (I didn't look all that hard, but I did look), so I set out to write my own disassembler. I quickly determined that trying to correlate a bunch of hand-written "observations" with the disassembler output was a lost cause, so I "enhanced" my disassembler to become what I term an Annotating Disassembler. This way, as I figure things out, I can "comment" the disassembly source directly, making for much easier reading. If anyone else out there is, um, er, determined, yeah, determined is a polite word, determined enough to want to do their own hacking on the 6800-family of Audi ECUs, here is my Annotating m6800 Disassembler [92KB] package. It is a uuencoded compressed tar file. For the cybercrud-impaired, that means it is a Unix-style file archive, compressed to save space (and so very much akin to zipped files in the PC world), then re-encoded in printing ASCII format to make it safe to email (historically, there have been many mail systems that trashed non-ASCII files...). The last time I tried to compile it was on a Sun SPARCstation running Solaris 4.x (read: quite a while ago). At least one fellow PCized it, but I've lost track of both it and him, so all I have is the Sun/Unix version of the source. I don't even know if it will compile successfully on a fully ANSI/Posix-complaint system. Caveat Emptor!

In addition, here is a sample set of input files for the disassembler. It is the stock Audi MAC-02 (B) ECU program [55KB] (as used on the UrQ family) and control file to produce a nicely formatted disassembly listing. It too is a uuencoded compressed tar file.

Once I had a disassembler in hand, the next step ("step" indeed; "odyssey" is more like it!) was to identify what did what. This was a non-trivial collaboration of a number of folks on the net, spaced out over many months. It involved a lot of experimental runs (make a change to the ECU code, go out and try it, and see what happens...) to gather data points. I actually have a ZIF socket in my ECU! What a Hoot! A lot of testing went into the final code (does it work in summer heat? in winter cold? in spring damp?). It co-existed with other engine mods (installation of Schrick cam, for example, lower-temp thermostat, etc.).

This is my final "release" modified High Performance MAC02 ROM [4KB] image (raw binary), and its related disassembly listing [52KB]. This MAC02 ROM image is reprogrammed in several ways. I make it "freely" available to one and all. Just remember, it's worth what ya pay for it! Money-back guarantee. You're on your own. Don't call me, and I won't call you. Caveat Emptor. And any other disclaimer totally absolving me of any and all possible knowledge and culpability for any possible socially-irresponsible behavior you mistakenly think I am encouraging. (It is vaguely possible that I might be persuaded to "sell" fully-programmed EPROM chips to folks who don't have access to a EPROM programmer. I am always open to a good bribe, if you can find me.)

And, for what it's worth, here is an alleged schematic of the MAC-02 ECU, gleaned from a fellow lunatic on the net. I don't know/remember if this is the "B" or the "F" model; it's in AutoCAD format [158KB]; or in a nice Juicy GIF [78KB] file. (Thanks Ian Finley for the .gif conversion; I unfortunately don't remember who originated the original AutoCAD schematic so I can't give proper credit here...).

MAC-02 (F) (Schrick) modifications:

This image is for the later MAC-02(F) ECU, and not [necessarily] for the earlier MAC-02(B). The two ECUs are largely interchangeable, but I have not verified all modes of operation. The "F" code works on the "F" box.

Other modifications to enliven the UrQ include:

Between the S4 turbo, advancing the engine timing, and retarding the cam timing, I have a much more streetable UrQ. In conjunction with the electrical rewiring (described below, under ranting and raving) I actually have a useable UrQ (headlights that light up rather than dimming down; fuse boxes that don't melt in order to protect their fuses from blowing, etc.). In fact, the UrQ has been my only wheels for a coupla years now (notwithstanding my opinion that anyone who relies on an UrQ as his only vehicle is a damn fool; Mea culpa). I haven't had to flatbed it since, oh, '93 or so . . .

Another area that received some substantial amount of attention was the engine cooling system. The stock thermostat is way too high, regularly resulting in heat-soak head temps of 250° (F) -- and that's all the higher my temp gauge goes -- in normal operation. Installation of a lower-temp thermostat (I'm currently running a 180° unit) along with the matching lower-temp radiator-fan switch is highly recommended. This limits engine (head) temperature to around 200° in normal operation and shutdown heat soak to about 220°/230° cylinder head temperature at worst.

Oddly enough (and counter-intuitive), the removal of the "auxilliary" radiator seems to result in better engine (cylinder head; I put the temperature sensor in the cyl head coolant outlet leading to the radiator) temperature regulation. It especially runs cooler at idle/low-speeds.

And the electrical system, well, see my Rantings 'n Ravings below. It got a lot of attention. The electrical system is without doubt the weakest point of the UrQ (and that whole generation of Audis, in general).

+++ Flame On +++

The UrQ electrical system is guaranteed to fail. Dangerously. It is the single most incompetent engineering job I have ever seen in a car. I mean, we all joke about English Sports Cars, and their Lucas electrics (You know, Lucas, Prince of Darkness; Q: Why do the English drink warm beer? A: Lucas refridgerators; blah blah blah), but my Audi made my Lotus look like a paragon of virtue and reliability. I would flunk any high school shop student who did that kind of wiring job. There is NO excuse for that kind of incompetence coming from any kind of reputable marque. Effin' Idiots!

+++ Flame Off +++

Deep Heavy Sigh. Oh well, live and learn.

For those of you seriously into things Audi, you should check out The Quattro List. Another interesting newcomer to the e-scene is AudiCar e-zine. (I think we're still hyphenating "e-zine", aren't we?).

And some other UrQ-related clickables:

Finally, to cap all of this UrQistic Rambling, I've extracted a few of my past rantings and ravings from The Quattro List, back when I was actively participating in the melee..

And these aren't really Rants'n'Raves so much as just "articles" I copied and posted for general edification.

These are past postings from others that I saved...

Back to RDH's Home Page


19-Dec-97 (Update: 28-Mar-99, 16-Jul-99, 17-Nov-99)

Robert D. Houk
email: MCrdhXI@tiac.net (delete the 1's - 11rdh11@...)