+ Reply to Thread
Results 1 to 8 of 8

Thread: Vr6 compression test w/ head spacer

  1. Member
    Join Date
    Jul 27th, 2010
    Location
    Albuquerque, New Mexico
    Posts
    461
    Vehicles
    B5 S4, 04 STi, 87 Jetta coupe (current)
    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
    Join Date
    Oct 4th, 2007
    Location
    Oakville Ont
    Posts
    2,717
    Vehicles
    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.
    Forced convection.... Now we grillin.
    Some times she goes, some times she doesn't.... Way of the road

    Rem 870 super mag in max 4 camo for sale. Pm me

  3. Member
    Join Date
    Jul 27th, 2010
    Location
    Albuquerque, New Mexico
    Posts
    461
    Vehicles
    B5 S4, 04 STi, 87 Jetta coupe (current)
    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
    Join Date
    Nov 13th, 2005
    Posts
    4,160
    Vehicles
    Mk3 VRT, Mk4 VRT, Mk4 VR
    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"

  5. Member
    Join Date
    May 12th, 2010
    Posts
    699
    Vehicles
    Mk3 VrT Gti
    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
    Join Date
    Nov 13th, 2005
    Posts
    4,160
    Vehicles
    Mk3 VRT, Mk4 VRT, Mk4 VR
    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
    Join Date
    Jul 27th, 2010
    Location
    Albuquerque, New Mexico
    Posts
    461
    Vehicles
    B5 S4, 04 STi, 87 Jetta coupe (current)
    04-19-2012 04:54 PM #7
    My motor is probably toast..

  8. Member masterqaz's Avatar
    Join Date
    Oct 4th, 2007
    Location
    Oakville Ont
    Posts
    2,717
    Vehicles
    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.
    Forced convection.... Now we grillin.
    Some times she goes, some times she doesn't.... Way of the road

    Rem 870 super mag in max 4 camo for sale. Pm me

+ Reply to Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts