84 UR-T tuning potential

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

In message <199803100755.HAA03429@mailhost.man.brite.co.uk> "Mark Warren" writes:

> Is it worthwhile doing all this to a 2144, or has a 2226 10v got much 
> more potential ?

You're actually _better_ _off_ doing it to a WR rather than to an MB.

You've missed out on some pretty heavy discussions about the 10V ur-quattros on 
this list.  Basically, the WR (your 2144, but we like to be specific because 
versions vary slightly between countries) is essentially mechanically 
controlled.  Most importantly, fuel enrichment at WOT is mechanical. The engine 
is thus pretty easy to tune up to around 300bhp with relatively standard 
components.
 
The MB (the UK ur-quattro version of the 2226 - a close relative of the USA's 
MC-1/MC-2 and the UK's 1B used in the 200TQ) is _NOT_ easy to tune.  The reason 
is that fuel enrichment at WOT is very largely under computer control, and the 
ECU has to be chipped (and it's a non-trivial custom job) for each specific 
mod. It is _NOT_ just a case of zapping boost and ignition tables - the 
code in the MB's MAC12D actually calculates, e.g., the fuel frequency valve 
duty cycle. It's a little easier with the USA versions because there is an OXS 
sensor in the exhaust system.  Some of us are working very hard on this problem 
at the moment -but several of us will assure you that modifying the MB's fuel 
system is not for the faint-hearted.  Maybe the solution will be to fit US-
style MAC14 electronics.

You would not just need to replace the engine.  There is a greater technical 
gulf between the WR and the MB (the two 10Vs) than there is between the MB and 
the RR (20V).  This is logical - the MB was the result of eight years' 
development - the RR of only two years.  You would have to replace the wiring 
loom, digital dash, ABS, fuel injection, gearbox, propshaft and rear 
differential. Not worth it.  The 1984 wiring diagram is 10 pages - the 1988 
version is 19 pages - gives an idea of the scale of the job!

The MB _is_ a much better car than the WR - it's very nearly the equal of the 
RR on the road.  But the improvements are in the TORSEN, in low rpm torque, and 
general driveability.  Cotton and silk.  None of these improvements would be 
any use to you in competition - and I'll even run the risk of re-opening a 
recent debate by suggesting that a lockable centre differential (WR) is better 
for hill-climbing and suchlike that the MB's TORSEN.

I'd suggest you have some serious discussions with people who know what they're 
talking about.  Aelred at Dialynx (Swindon) and Martin at BR Motorsport 
(Leamington) for a start - then perhaps Dean Zaman at Audi Only in Manchester.  

Audi Only are having a workshop day in Manchester on 22 March.  Give Dean a 
call on 0161 205 2732.  I'll certainly be there.

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