Shaving head on MC engine? BTDT's?

[Todd Phenneger]

The Compression ratio in my 4ktq is about 8.5 to 8.8:1.   And
all I can say Torque.   Its the only turbo motor I've driven 
(well, ok, early 10v motor, the 20vt blows its socks off)  BUt
the only 10vt I've driven with low end response.  It pretty much
drives like a 4kq untill the turbo kicks in.  
   But, I've got timing issues.  My ignition LOVES to retard. 
But I'm not sure it if is the higher compression of the ur-q
flywheel I"m running.  That should have retarded the timing with
that flywheel which shouldn't make it detonate less so I'm a
little confused.  
   so what I'm saying, is the benefits are great, but if you
have timing issues then you may need a remapped ECU.  But I love
my 4ktq.    as I'm sure Gary loves his Coupe Turbo. 
 
  l8r
     TOdd

--- auditude at neta.com wrote:
> Hi Gary,
> 
> How exciting!  I've got my own questions, for you and anyone
> else 
> willing to answer.
> 
> Is there anything you can tell me about the K24 change?  Does
> it 
> limit max boost?
> 
> Do you know the order in which upgrades should be done?  Chip,
> 
> wg spring, bypass valve, single pass intercooler, k24, 2 piece
> em?
> 
> Do you have to fabricate a pipe to install the single pass 
> intercooler, or are pipes available?
> 
> Are there any reasons that one shouldn't use MC-2 equivalent
> c/r 
> with an MC-1 ignition system?
> 
> Thanks,
> 
> Ken
> 
> On 12 Jan 2001, at 10:35, Gary Erickson wrote:
> 
> > In celebration of my '89 200q's impending 200K mile
> birthday, it's about
> > to go under the knife for a full top end rebuild and
> installation of a
> > 20V single-pass intercooler and K24 turbo.
> > 
> > (Just to avoid confusion, let me state that my car is an
> early '89 with
> > the MC-1 engine that came stock with the lower 7.8:1 CR and
> K-26 turbo.)
> > 
> > An Audi-owning friend of mine asked "While you have the head
> off, why
> > don't you shave it a bit to bump the compression ratio up
> closer to the
> > MC-2 engines?"  (8.4:1 CR if I remember right)
> > 
> > I know from talking to a couple of source and peering at the
> family
> > album, that the CR increase in the MC-2 came from a
> different piston
> > design.  But I'm not planning to tear into the bottom half
> unless I see
> > something wrong while the head is off; so I'm curious as to
> whether this
> > would be an acceptable alternative.  (And likely cheaper,
> I'm guessing.)
> > 
> > Does anybody have any comments about this procedure? 
> (Either BTDT, or
> > good reasons not to are both welcome!)
> > 
> > And yes, I am aware of the slight change in cam timing that
> would occur
> > with the head shaving, but I'm already planning to install
> an adjustable
> > cam gear to play with, so I could easily dial out this
> issue.
> > 
> > TIA!
> > 
> > -Gary


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