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General Information => FAQ/Tech Tips/Please Read First => Topic started by: subsonic on February 10, 2008, 03:27:59 pm

Title: CC's above piston and compression ratio / pre cup cc volume
Post by: subsonic on February 10, 2008, 03:27:59 pm

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
******************************************

Title: Re: CC's above piston and compression ratio / pre cup cc vol
Post by: saurkraut on February 11, 2008, 08:13:50 am

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?

Title: Re: CC's above piston and compression ratio / pre cup cc vol
Post by: MJF on February 11, 2008, 09:25:47 am

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.

Title: CC's above piston and compression ratio / pre cup cc volume
Post by: jimfoo on February 11, 2008, 10:14:23 am

And I assume the CR is for a 1.6 as a 1.9 would have a different CR for the same volume.

Title: CC's above piston and compression ratio / pre cup cc volume
Post by: saurkraut on February 11, 2008, 10:51:53 am

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

Title: CC's above piston and compression ratio / pre cup cc volume
Post by: MJF on February 11, 2008, 01:25:49 pm

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.