[Vwdiesel] Latest fun :-)

LBaird119 at aol.com LBaird119 at aol.com
Tue Feb 7 02:52:38 EST 2006


  For those that don't know, we now have a two axis CNC, Bridgeport copy, 
milling machine!  Yay!  Now I can spend all that spare(???) money on tooling!  x 
axis screw got the end broken off in shipping even though the motor had been 
removed, so the screw is on its way back to the seller, who very nicely 
volunteered to fix it for shipping only.  :-)
  This now brings up my option for getting the Rabbit running again.  I've 
contemplated dropping the CR to around 19:1 for better performance and mileage.  
I dropped the Jetta from not even qualifying for a one notch gasket, to 
putting in a three notch.  It seems to rev quite a bit more freely but with its 
mileage, it's no indicator whether it should increase noticeably or not.  I 
figure I got about a 1 point drop in CR.  
  When I calculated things out I came up with needing to mill 1mm off of the 
pistons, not counting the recesses, to go from 23:1 to ~19:1.  That's with 1mm 
oversize pistons, which works out to very near a full 1500cc displacement.  
Anybody care to work it out and see if they come up with the same amount?
  Has anybody else done any sort of CR drop and noticed anything?  I do have 
to let the glow plugs go for the full cycle or it won't start but it DOES 
still start well.  It just used to only have to glow a bit and that was good 
enough.  I got ONE tank that was a couple mpg better than its previous best but 
that's it.  It does wind out more like when I was testing propane on it.  
Afterwards the propane mostly felt like simply adding more fuel, smoke and all.
     Loren


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