To MB or MC?

[Bob]

Phil...
As usual, thanks for the ton of info, thats just great.  It seems clear which
direction I want to go in now...
Thanks again.
Bob

isham-research.freeserve.co.uk at pop.pol.net.uk wrote:

> > Can anyone tell me the major differences between the MB and MC motor? I
> > need to build one for high horsepower, and would like to know which is a
> > better candidate.
>
> Well, since I've driven 110,000 miles behind an MB and 42,000 behind an
> MC, both of which I still own and wrench ...
>
> The MC is a hydraulic tappet engine packaged for the Type 44 engine bay.
> Two forms - single knock sensor controlled by MAC11 and twin knock
> sensor controlled by MAC14.  Both forms support emission controls -
> OXS sensor and the like.
>
> A version of the first MC was adapted for european use by deleting the
> OXS sensor, which was not a legal requirement at the time.  This was the
> 1B engine controlled by the MAC12D - again packaged for the Type 44
> engine bay.  Orin Eman has shown by disassembly that the MAC12D code
> is identical to the MAC11 code with the (very few) variables and code
> dealing with emission controls deleted.
>
> The MB is exactly this engine - single knock sensor and no OXS -
> repackaged to fit into the Type 85 engine bay.  It also uses the MAC12D,
> although some (not all) MAC12Ds found in MB-engined cars are marked
> 'ur-quattro only'.  I think this is the only place I've seen the
> word 'ur-quattro' used officially by Audi at the time of production.
>
> Physically (crank, pistons, cam, etc) all four engines are almost
> identical.  I believe the MC-2 is a minor exception because of some
> cam changes, but that's about all.  The peripherals (air filter box,
> plumbing, etc.) are different shapes although the key fuel injection
> components (metering head, frequency valve, injectors, system pressure
> regulator, control pressure regulator) are the same.
>
> Essentially, for North American ur-quattro owners, the MB's peripherals
> provide a 'stock' way of mounting an MC engine into a Type 85.
>
> There are photographs of a Type 85 MB installation and some other details
> on Scott M's web site.
>
> --
>  Phil Payne
>  UK Audi quattro Owners Club
>  http://www.isham-research.freeserve.co.uk/quattro
>  Phone +44 7785 302803   Fax: +44 7785 309674