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    1. Member
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      04-18-2012 11:09 AM #1
      I recently had a compression test done on my motor, the #'s seem a little low to me, even with a lower compression head spacer..

      What should the compression #'s be for a vr6 with a 9:1 head spacer?

      Any input appreciated!

    2. Member masterqaz's Avatar
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      New 04 pd100 Old setup 94 JTI Vrt 60-1 .58ar exh obd2 440 racefile 20psi/meth
      04-18-2012 11:34 PM #2
      Well what are the numbers your getting. As long as they're with in a certain number of each other it should be alright. Unless the numbers are really low. You can start something with 100psi, may not run nice but engines will run that low.

      I would expect to see on a 8.5-1 hs around 120-150psi a cylinder. Believe a buddy of mine tested his golf at about 130-140 range.

      The real problems start when there's a large difference and balance is lost.
      Coming soon 4dr pd golf on air dipped blue with hitch racks and skid. Real work horse
      Automatic cause shifting short ratio sucks

    3. Member
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      04-19-2012 01:09 AM #3
      Quote Originally Posted by masterqaz View Post
      Well what are the numbers your getting. As long as they're with in a certain number of each other it should be alright. Unless the numbers are really low. You can start something with 100psi, may not run nice but engines will run that low.

      I would expect to see on a 8.5-1 hs around 120-150psi a cylinder. Believe a buddy of mine tested his golf at about 130-140 range.

      The real problems start when there's a large difference and balance is lost.
      cyl #1 130-140sh, cyl #2 115ish cyl #3 90ish cyl #4 120 cyl #5 120 cyl #6 115

      so maybe its a 8.5:1 spacer and I have one ****ed cylinder..

    4. Member V-dubbulyuh's Avatar
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      04-19-2012 12:52 PM #4
      IIRC, 9:1 I usually see ~ 170, been a while since I've checked tho.

      Your numbers seem very low to be honest.
      "OP sounds like a MKIV guy"

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      04-19-2012 02:26 PM #5
      My 8.5:1 was 160-165 across for a long time.....was
      OBD1, Mk3 12v, 3L, HG, 8.5, JE, stock rods, 263, 3"DP to 3" MBS, Kinetic Mani, t3/t4 .63ar, Intercooled, PW39, C2 36# 4 bar, IE 044 surge, Stock intake, Peloquin, AEM truboost/uego/fp, Mocal OC

    6. Member V-dubbulyuh's Avatar
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      04-19-2012 02:51 PM #6
      Quote Originally Posted by vergessen wir es View Post
      My 8.5:1 was 160-165 across for a long time.....was
      Sounds correct. Have not checked the comp on my 8:5 for a while either though. OP's numbers are just way too low for whatever compression ratio he is using.
      "OP sounds like a MKIV guy"

    7. Member
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      04-19-2012 04:54 PM #7
      My motor is probably toast..

    8. Member masterqaz's Avatar
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      New 04 pd100 Old setup 94 JTI Vrt 60-1 .58ar exh obd2 440 racefile 20psi/meth
      04-19-2012 06:07 PM #8
      160 on a 9-1 would be ideal, and expected for a fresh motor. something worn in could be 20 less or more, you'd also be experiencing blow by and whatever pcv system you have in place would def be showing you that you do have rather more blow by.

      Being that you have fairly steady numbers 2,4-6, 1 being slighty higher and 3 being the lowest. I would do a leakdown test on 3 at the least. A big drop like that maybe a burnt valve. 50 psi difference will cause a nice shake and studder.

      Sounds like you'll be pulling the head either way but I would still leak down test 3rd so you'd have an idea of what you'll be diving into.
      Last edited by masterqaz; 04-19-2012 at 06:09 PM.
      Coming soon 4dr pd golf on air dipped blue with hitch racks and skid. Real work horse
      Automatic cause shifting short ratio sucks

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