RE: Quattro rear diff.

["David G. Lawson" <71344.2441@compuserve.com>]

Hi John,

>In the September 1984 issue of Sports Car Graphic there is a very good
>article comparing the 1984 TQC and the 1984 4KSQ.  Under drivetrain
>specifications, they list an axle ratio of 4.11:1 for the 4KSQ and an axle
>ratio of 3.89:1 for the TQC.  Are the 4KSQ diffs a direct replacement into
>the TQC?  If so, doesn't this seem to be a very affordable way to improve
>quickness?  Wouldn't a TQC with 4.11 gearing perform better on the track?

There have been a couple of people who have performed this swap on their
TQCs. Supposedly, it has the equivalent effect of raising the horspower
a significant amount. I haven't drove a TQC with this mod yet. I have 
plotted the gear charts and it does quicken up the accel at the expense
of top speed. Remember that in a quattro you have 2 ring and pinions,
the front and the rear, so to do the swap you need to change out the
transmission and the rear diff. In the front you could probably just change
out the ring/pinion but it is much cheaper just to install a used 4kq tranny.
I hear the set to get is from an 84 4000q.  

>The article also listed the 4KSQ as having a larger bore, and higher
>compression ratio.  Wouldn't the affordable hot ticket be mounting a 4KQ
>short block into the TQC?

The 4kq has a 2.2l vs. the 2.1l of the TQC. The TQC has to have the lower
comp ratio for the turbocharged nature of the engine. I wouldn't run a TQC 
with a 4kq short block without some type of knock sensing and smart 
boost control system. You will also loose the oil squirters on the 
backside of the piston with the 4kq block.
  
>As an aside, the article concludes that the TQC is worth the $35,000 (1984),
>but is not twice as good as the 4KSQ at $17,000 (1984).  Not what I wanted
>to hear since I'm selling my '85 4KSQ to buy a TQC!

I can see how the mags came to this conclusion. (sorry if I offend any one 
of the mag orientation or nationality) It probably wasn't worth double a 4kq. 
But 12 years later... You get to make the call here. How many ur-q's have
you seen/driven? If interested there are a few in the papers around Denver
for sale.

If possible I would like to get a copy of this article. I don't have this one
and would like to add it to my collection.

Hope this helps.
-
Dave Lawson  dlawson@ball.com
                     71344.2441@compuserve.com
83 tqc
86 gt
93 gmc safari awd