Compression test results

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  • s2_bo
    S2Forum Zealot
    • Oct 2005
    • 6067
    • Home: United Kingdom Current: France

    #1

    Compression test results

    I ran another compression test today to see if the results would have changed much since the rebuild.

    The results are:

    The first column is just after rebuild: 0miles. The second one is 3 months after rebuild: 1500miles

    Dry: ----------------- Dry:

    Cyl 1 - 12.70bar ------- Cyl 1 - 13.50bar
    Cyl 2 - 13.10bar ------- Cyl 2 - 13.80bar
    Cyl 3 - 12.30bar ------- Cyl 3 - 13.70bar
    Cyl 4 - 12.80bar ------- Cyl 4 - 13.80bar
    Cyl 5 - 12.10bar ------- Cyl 5 - 13.00bar

    Wet: ----------------- Wet:

    Cyl 1 - 14.00bar ------- Cyl 1 - 16.30bar
    Cyl 2 - 14.00bar ------- Cyl 2 - 16.00bar
    Cyl 3 - 14.10bar ------- Cyl 3 - 15.40bar
    Cyl 4 - 14.05bar ------- Cyl 4 - 16.30bar
    Cyl 5 - 13.90bar ------- Cyl 5 - 16.00bar


    On both accounts cyl 5 is a bit down, even still after i have ran the engine in a bit its holding .8bar less then cyl 4.

    During the wet runs i tried to use an equal amount of oil in each cylinder.

    The car runs ok, its giving .7 to .8bar boost at the moment on stock 3b software and is due a remap soon.


    Can someone tell me if the above looks ok, or if it looks a bit problematic?
    91 S2 coupé - RIP
    98 S8 - Luxury barge
  • AndyP
    S2Forum Zealot
    • Feb 2004
    • 6049
    • Country: England

    #2
    According to the 3B Audi manual they should be 7-13bar when new with a maximum difference of 3bar between cylinders, so yours look spot on.
    sigpic
    1991 Audi S2 3B - 2.5 Stroker engine
    1997 A6 2.5TDi quattro avant - C4
    1976 RD250E / 350LC cafe racer

    Comment

    • s2_bo
      S2Forum Zealot
      • Oct 2005
      • 6067
      • Home: United Kingdom Current: France

      #3
      Ahh that's not so bad then, i thought max allowance was 1 bar.

      Cheers Andy
      91 S2 coupé - RIP
      98 S8 - Luxury barge

      Comment

      • AndyP
        S2Forum Zealot
        • Feb 2004
        • 6049
        • Country: England

        #4
        I'd say that Audi are being a bit 'generous' with that 3bar figure, most people aim for 1bar so your still ok.
        sigpic
        1991 Audi S2 3B - 2.5 Stroker engine
        1997 A6 2.5TDi quattro avant - C4
        1976 RD250E / 350LC cafe racer

        Comment

        • 4WheelDrifter
          S2Forum Zealot
          • Oct 2004
          • 5773
          • Country: Devon

          #5
          Looking good Bo. Bedding in nicely.

          I can't remember which rings we used on your engine. I know I used 1 different set on my engine. Funnily enough cylinder number 5.
          SS

          Comment

          • S2central.net
            Retired OG Mod
            • Jul 2003
            • 16590
            • Country: Northern Ireland

            #6
            Chill cappin Bo - looks good to me... A spread of less than 1 bar across all five pots.

            0.8bar on stock 3B software is fine... Do you want fries with that or what ?
            Paul Nugent
            Webmaster http://S2central.net
            Administrator http://S2forum.com

            1994 S2 Coupe ABY - aka Project Lazarus
            2001 A6 allroad 2.5TDi - family tank
            2003 S4 Avant 4.2 V8 - daily burble

            Purveyor of HomeFries and Exclusive agent for Samco hose kits (S2/RS2)

            There are only 10 kinds of people that understand binary - those that do, and those that don't

            Comment

            • s2_bo
              S2Forum Zealot
              • Oct 2005
              • 6067
              • Home: United Kingdom Current: France

              #7
              Yeah, we used 4 packs of rings from gsf and one pack from audi, im guessing cyl 5 got the oem one.

              Thanks for the offer of home fries Paul, but im going to go for a custom map which will be best for the combination of parts i have bolted to the car.. I hope so anyway.
              91 S2 coupé - RIP
              98 S8 - Luxury barge

              Comment

              • 20Vcqdriver
                S2Forum Maniac
                • Jun 2007
                • 829
                • Country: United Kingdom

                #8
                Just done a compression test on mine over the last few days in case I had a problem, all cylinders showed 160psi (11.0bar)after 108k miles so yours looks about right for a new engine.
                1986 Coupe q - 2281cc 3B, chargecooler, 2.75" exh & downpipe, ported head, water injection, CGR box, modified MD357 turbo, 440cc injectors, high power coil.
                2004 A4 2.5TDi convertible, re-mapped to 180bhp
                2011 A5 sportback 3TDi-Backbox delete, remap

                Comment

                • s2martyn
                  Banned
                  • Apr 2008
                  • 408
                  • Country: United Kingdom

                  #9
                  mine measured 150psi across the range.with a fresh engine thats only ever been started up..i have 8;1 compression pistons with 2 headgaskets on

                  Comment

                  • MrVain
                    S2Forum Enthusiast
                    • Oct 2008
                    • 189
                    • Country: Sweden

                    #10
                    looks good

                    My ABY had this last summer before i took it apart 230000km

                    cyl 1 8,2 bar
                    cyl 2 8,2 bar
                    cyl 3 8,1 bar
                    cyl 4 7,9 bar
                    cyl 5 7,8 bar

                    This was a dry test..

                    Still ran 13:34 on 402m

                    Comment

                    • s2_bo
                      S2Forum Zealot
                      • Oct 2005
                      • 6067
                      • Home: United Kingdom Current: France

                      #11
                      Thanks guys, much appreciated.
                      91 S2 coupé - RIP
                      98 S8 - Luxury barge

                      Comment

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