CC's above piston and compression ratio / pre cup cc volume - FAQ/Tech Tips/Please Read First - VWDiesel.net The IDI, TDI, and mTDI source.

• CC's above piston and compression ratio / pre cup cc volume by subsonic on 10 Feb, 2008 15:27
• Found this in a old post by racer-x:
  
  
  Here's a "chart" of volume above the piston vs. compression ratio.  Also included is a quote from Dave with pre cup volumes:
  
  

  Quote from: 935racer

  I am working on compiling as much info as possible on the vw idi pre cup inserts. Today I bought a brand new 1.9 pre cup, and I pulled a 1.6td precup and a 1.6 na pre cup and measured the volume.
  
  1.9td-5.8cc
  1.6td-5.2cc
  1.6na-5.5cc
  
  
  cc above piston | compression ratio
  18 | 23:1
  *********************************************************************
  18.5 | 22.4054054054054:1
  *******************************************************************
  19 | 21.8421052631579:1
  *****************************************************************
  19.5 | 21.3076923076923:1
  ***************************************************************
  20 | 20.8:1
  **************************************************************
  20.5 | 20.3170731707317:1
  ************************************************************
  21 | 19.8571428571429:1
  ***********************************************************
  21.5 | 19.4186046511628:1
  **********************************************************
  22 | 19:1
  *********************************************************
  22.5 | 18.6:1
  *******************************************************
  23 | 18.2173913043478:1
  ******************************************************
  23.5 | 17.8510638297872:1
  *****************************************************
  24 | 17.5:1
  ****************************************************
  24.5 | 17.1632653061224:1
  ***************************************************
  25 | 16.84:1
  **************************************************
  25.5 | 16.5294117647059:1
  *************************************************
  26 | 16.2307692307692:1
  ************************************************
  26.5 | 15.9433962264151:1
  ***********************************************
  27 | 15.6666666666667:1
  ***********************************************
  27.5 | 15.4:1
  **********************************************
  28 | 15.1428571428571:1
  *********************************************
  28.5 | 14.8947368421053:1
  ********************************************
  29 | 14.6551724137931:1
  *******************************************
  29.5 | 14.4237288135593:1
  *******************************************
  30 | 14.2:1
  ******************************************
• #1 by saurkraut on 11 Feb, 2008 08:13
• Quote from: subsonic

  
  1.9td-5.8cc
  1.6td-5.2cc
  1.6na-5.5cc
  
  quote]
  
  Are those the volumes of just the swirl chamber covers, or the whole swirl chamber, including injectors, heat shields, and glow plugs?
• #2 by MJF on 11 Feb, 2008 09:25
• Quote from: saurkraut

  Quote from: "subsonic"

  
  1.9td-5.8cc
  1.6td-5.2cc
  1.6na-5.5cc
  
  quote]
  
  Are those the volumes of just the swirl chamber covers, or the whole swirl chamber, including injectors, heat shields, and glow plugs?

  
  
  Just covers, I´ve measured 10-12cc from different heads.
• #3 by jimfoo on 11 Feb, 2008 10:14
• And I assume the CR is for a 1.6 as a 1.9 would have a different CR for the same volume.
• #4 by saurkraut on 11 Feb, 2008 10:51
• Thats interesting. I've computed the following from engine data tables:
  
  1.5 Swirl chamber volume 11.457 cc
  
  1.6 Swirl chamber volume 12.794 cc
  
  1.9 Swirl chamber volume 16.376 cc
• #5 by MJF on 11 Feb, 2008 13:25
• Quote from: "saurkraut"

  Thats interesting. I've computed the following from engine data tables:
  
  1.5 Swirl chamber volume 11.457 cc
  
  1.6 Swirl chamber volume 12.794 cc
  
  1.9 Swirl chamber volume 16.376 cc

  
  
  These include chamber in piston top and piston to head clearance too.