boost comes, conrods go! 3B ignition?

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  • Rax
    S2Forum Tinkerer
    • Aug 2005
    • 7
    • Home: Estonia

    #1

    boost comes, conrods go! 3B ignition?

    Hello! I have a problem with braking conrods. After 1,5 bar , the A/F meter shows green light, everything should be normal, but... http://www.zone.ee/calibrablack/S2/IM002703.jpg and the car doesnt move so good as it should be. when its lower than 1,5 bar then its ok. Im using K24/7200 and RS2 E/manifold. Ive changed the distributor gear (BRONZE) , cnocksensors (both), checked everything, the computer shows no errors in ECU. Has anybody had same problem.
    1/4 mile 11.656 @ 197km/h
    1/8 mile - 7,73 s @ 154km/h
    1 km - 249km/h
    1 mile - 269km/h
  • s2_bo
    S2Forum Zealot
    • Oct 2005
    • 6067
    • Home: United Kingdom Current: France

    #2
    Ouch!!!
    91 S2 coupé - RIP
    98 S8 - Luxury barge

    Comment

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

      #3
      More proof that the K24-7200 can bend rods.
      SS

      Comment

      • prr
        S2Forum Tinkerer
        • Oct 2005
        • 7
        • Country: Estonia

        #4
        actually, it's not a turbo, it's the fuc*ing ignition problem...i think...
        Last edited by prr; 5 April 2006, 21:41.

        Comment

        • Jon441cc
          S2Forum Fiend
          • Dec 2005
          • 2061
          • Country: United Kingdom

          #5

          Take a look @ this thread http://www.s2forum.com/forum/showthread.php?t=14170
          sigpic

          Comment

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

            #6
            AnLe wasn't as lucky...



            Don't ask where the other rod went.

            You seem to have gained one.
            SS

            Comment

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

              #7
              Originally posted by prr
              actually, it's not a turbo, it's the fuc*ing ignition distributor problem.
              Ah, that old problem. Audiman has a BTDT on that. Hence this thread
              SS

              Comment

              • newsh
                S2Forum Obsessed
                • Aug 2003
                • 16226
                • Country: United Kingdom

                #8
                This has been known to happen after steam cleaning the engine bay of a 3B.

                S2 Coupe 3B Project


                Ur quattro restoration

                S2 Avant

                Boost is the new rock and roll!
                sigpic

                Comment

                • S2Racing
                  S2Forum Tinkerer
                  • Mar 2006
                  • 1
                  • Country: Norway

                  #9
                  I`ve got the same problem with my 91 coupe, and I think it`s an ignition-problem..
                  It accures only on max pressure..

                  Comment

                  • kwlw
                    S2Forum Extremist
                    • Sep 2004
                    • 1025
                    • Country: Lithuania

                    #10
                    Originally posted by S2Racing
                    I`ve got the same problem with my 91 coupe, and I think it`s an ignition-problem..
                    It accures only on max pressure..
                    You need a better spark to ignite fuel on high boost. That's physics. All normal spark plug/ignition system testing/development is done in pressure chamber. That is because there is more fuel vapour/air between the electrodes - you need stonger (also maybe higher voltage) pulse to break that.

                    Sau
                    200 20vt 88' 3b, human carrier
                    CQ typ85 with AAN inside, see project blog at http://kwlw.blogspot.com

                    Comment

                    • Rax
                      S2Forum Tinkerer
                      • Aug 2005
                      • 7
                      • Home: Estonia

                      #11
                      I have tried with Denzo iridium (IK22) and NGK platinum. And allways in fifth silinder, once was fourth and fifth (both). What is the best solution to get higher voltage? any examples
                      1/4 mile 11.656 @ 197km/h
                      1/8 mile - 7,73 s @ 154km/h
                      1 km - 249km/h
                      1 mile - 269km/h

                      Comment

                      • repo
                        S2Forum Maniac
                        • Dec 2004
                        • 893
                        • Country: Finland

                        #12
                        I'm pretty sure You detonated. You need standalone / remap.

                        If You want better spark for dizzy-ignition, You need CDI amplifier. But I can't see how these relate to bending rods...

                        In case there is no situation, where the nose of the distributor points in middle way of two contacts in cap, and under high boost hits the spark into wrong cylinder.
                        Everything less than 2 bar is considered to be naturally aspirated

                        Comment

                        • newsh
                          S2Forum Obsessed
                          • Aug 2003
                          • 16226
                          • Country: United Kingdom

                          #13
                          Thats a good point, have you checked your static timing very carefully? turn the engine in the direction of travel so the marks line up. Poor HT leads could also be a problem?

                          Or too much boost at low RPM? = too much torque..

                          S2 Coupe 3B Project


                          Ur quattro restoration

                          S2 Avant

                          Boost is the new rock and roll!
                          sigpic

                          Comment

                          • Mihnea
                            S2Forum Extremist
                            • Jul 2003
                            • 1288
                            • Home: Belgium Current: United Kingdom

                            #14
                            This problem is only due to detonation, it has nothing to do with the ignition coil/spark plugs/leads/ECU output stages whatsoever. It is only detonation that bends rods like that. If the ECU is mapped properly with NO detonation at all EVER, then nothing like this will happen, newsh is running 1.7-1.8 bar on an RS2 turbo and stock 3B rods and as far as I'm aware his rods are still straight... and he's only one of many...


                            HTH,

                            Mihnea
                            '98 Silver Grey 2.7T S4, dual 2.75" turbo back exhaust with no cats, FMIC, BIG injectors, 10 Bar motorsport fuel pump, modded RS4 turbos, tubular exhaust manifolds, custom intakes, RS4 MAF, Bilstein PSS9, H&R ARBs, 19" BBS CH, custom remap, 511 BHP/505ft-lbs

                            www.MRCTuning.com
                            info@MRCTuning.com
                            Workshop Directions

                            Comment

                            • AJ ES
                              S2Forum Tinkerer
                              • Mar 2006
                              • 6
                              • Country: Scotland

                              #15
                              Plenty pictures of bent rods but detonation also leaves its mark on rings , piston crowns and combustion chambers.
                              Why don't you clean the piston crowns and combustion chambers (carefully) and post a photo of them.

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