[Vwdiesel] Add just turbo to NA?

[LBaird119 at aol.com]

In a message dated 4/1/2012 8:11:57 A.M. Pacific Daylight Time,  
val at mongo.mongobird.com writes:

The EGT  issues are driven by how much fuel is injected, and presumably 
with 
a  blower, there would be no more injection than on the existing engine.   
A "leaner" burn will raise the temps, but is unlikely to cause a  problem,
as the valves, cylinderhead and pistons tend to be fairly robust,  and 
they are far from marginal in the NA engine.
 
  One misunderstood aspect of diesels is they don't run lean.   Rich yes, 
which 
is black smoke.  They will run as lean as possible given the air, fuel  and 
load, 
otherwise "lean" it out and you decrease speed until the engine again  
achieves 
load/lean equilibrium.  Thus they can't run hotter when lean.   They tend 
to run 
hotter when rich or when the timing's retarded.  Pretty much the  opposite 
of a 
gas engine since it causes more afterburn, which heats up the engine.



Another factor is that you will probably want to run  synthetic oil in the
engine.  On my 91, I do frequent oil changes, and  synthetic would cramp 
my style.  The synthetic is necessary to avoid  temperature polymerization
of the oil in the turbo bearing areas.  On  the other hand, changing the 
oil filter is such a pain in the 91 that I  would probably welcome less 
frequent changes.
 
  Cheaper yet is to let it idle a few to several seconds before  shutting 
the 
engine down.  Most coking comes from hot shutdown rather than   hot 
running.  It's rare that I end up stopping somewhere where the turbo  is 
really still hot.  Most of the time you toodle along a bit before you  stop 
and the temps are safely down by the time you shut down.



All this said, I should disclose that I own a 99, 02 and 03  TDI, in 
addition
to the 91 IDI, and a gaggle of other diesel engines on  various equipment.
While I find the 91 is the most comfortable, nicest  starting and running 
car I own, the high engine RPMs at highway speeds has  me buying TDIs for 
my kids, and shying away from the IDI engines.   That said, the around town 
mileage on the IDI is better than the TDIs and  the trip mileage (highway
speeds) is better on the TDIs.
 
  Which transmission do you have in the '91 Val?  They aren't too  bad with 
the higher ratio trannys but the low ones, like the Eco  had  
(A_something_X) 
is really low and kicks the rpm way up there.  Great for the drag  strip!



Again, my take is that it can't hurt, and a turbo has  advantages, 
but the benefit may not be worthy of the expense and  effort.
 
  Most of the actual benefit is in driveability.  The mpg  increase is 
minimal 
and hard to say if it'd technically pay for itself.  The Fahrvergnügen  
increase 
is... priceless.  :-)



PS I have a friend who put a  blower on a NA Ford 1910 tractor...about 2000 
hours ago, and reports no  problems, except that his exhaust is much 
cleaner, and the tractor runs  quieter. Last we talked about it, his 
compression
was fine, and as a result  he has not pulled the head and has nothing to
report on valve condition.  



Dad and I have been contemplating adding a turbo to a couple of the  
tractors 
and the Kubota RTV900.  The Kubota really needs one and the stupid  kits 
are >$2000!!!  My uncle doesn't want it done on any of the  equipment 
because 
it's "one more thing to go wrong" or "it will put more wear on the  engine, 
make 
it run hotter" (make the sky fall, bring on the apocalypse or make the  
interpretation 
of the Mayan calendar correct.  ;-)
     Loren