[Vwdiesel] Mileage

[Rudy]

84 Jetta TD, I recently rebuilt my Garret Turbo (seals and bearings, ect.)
and my Injectors (nozzles, pop pressure 2300 psi).  I'm getting consistent
38 mpg combined City and Freeway driving and recently got 44.47 mpg on a
Freeway trip with two 150 mile legs.  This was driving between about 62 and
70 mph and using my Laptop and GPS program to verify speed and miles driven.
I expect I'll get more with a longer Freeway trip using multiple tanks of
fuel.
 
I use Power Service Diesel additive in every tank.  I'm going to play with
the Injection timing a little and see if I can do better but I'm pretty
happy with this.
 
Funny thing, my Exhaust Pipe broke off at the weld on the front of the
Muffler and I was running with that for a while, I noticed the Turbo spooled
up a little sooner and it seemed to breath a little better without the
Muffler.  I recently had to do an emissions test and had to install a
Muffler and Tail Pipe with a smaller Pipe that the one that broke off (all I
could find for 84 TD).  I notice the Turbo doesn't spool up like it did
without the Pipe but the mileage seems to have increased considerably.
 
I'm wondering if maybe the Turbo is spooling up but not enough to increase
the Fueling as soon or as much or whatever???  Anyone have any thoughts on
this?
 
Rudy