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  • blew the engine again

    Unfortunately my engine collapsed again. I did allot of bin-tuning the last month and the car seems to be strong and reliable up to 250km/h. I never got above, too much traffic.

    Now it was time to verify how long the engine can stand topspeed. Very very late at night i went on the autobahn an held the speed at 278km/h (286 on speedo) at 16psi and rev limiter @6600. After 3 minutes i felt a power loss and smoke in the rear mirror. I will get off the heads soon to verify the damage.
    I think I need a reliable knock detection.

    My spare engine is ready with new bearings and good compression-test. Tomorrow engine-change will be completed and the car is on the road again.

  • #2
    Take some pictures when you pull the heads!!!! So you were able to get it home without it being towed though?

    I keep forgetting youre probably asleep right now..no response till tomorrow haha
    Who are you to tell me my uninformed opinion is wrong?!?!?

    Expert: He who has made all the mistakes there is to make in a given field.

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    • #3
      rarely do I see a car take sustained high boost and survive...
      Lance 'never-ending 88na2t project' Landry
      I sell Z stuff when I'm not being lazy.
      Trace cell phones via GPS: http://www.phonetrace.org

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      • #4
        Sounds like you need higher gears Dino. That'd probably make the super high speed driving easier on your engine.

        Oh, and also, holy crap man, that's haulin some serious ass. How stable are these cars at that kind of speed?
        Attached Files
        My beloved Z:1987 2+2 NA2T w/30a swap.
        My black sheep: 88ss parts car (pretty much stripped and gone)
        207k miles and counting. Turbo'd since 155k.

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        • #5
          As Mencia would say "Di Di Ri"
          Attached Files
          Shiro #443

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          • #6
            Dino wrote: Unfortunately my engine collapsed again. I did allot of bin-tuning the last month and the car seems to be strong and reliable up to 250km/h. I never got above, too much traffic.

            Now it was time to verify how long the engine can stand topspeed. Very very late at night i went on the autobahn an held the speed at 278km/h (286 on speedo) at 16psi and rev limiter @6600. After 3 minutes i felt a power loss and smoke in the rear mirror. I will get off the heads soon to verify the damage.
            I think I need a reliable knock detection.

            My spare engine is ready with new bearings and good compression-test. Tomorrow engine-change will be completed and the car is on the road again.
            I might not be the sharpest stick in the woods but isnt 3mins of 16 psi crazy?
            I'm still turboless...but it seems to me that is seriously testing the limits of the Vg30.
            I dunno...someone school me.
            (I take it you blew the headgasket?)
            http://www.vgpowered.com
            Bridging the gap between VG communities...

            Z shirts and more http://www.cafepress.com/zcargifts

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            • #7
              :shock: :shock: :shock: :shock: HOLY SHIT 177mph for 3 minutes I would say you have no detontion if it lasted for 3 minutes. That is just a lot of stess. Like trying to swim across the gulf of mexico, eventually you are going to get worn out and probably drown. I would suggest a better head gasket that is overtorqued. And maybe some better rings to go with that.
              KILL HADJI

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              • #8
                its possible he wasn't detonating and just melted something say like a piston or cooked all the turbo seals from the heat

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                • #9
                  hmm, yes i admit, 3 minutes is a long time but if you want to chase an m3 or a porsche the car must/should stand this. I am very keen on seeing the 6´th cylinder after opening, i will post pics

                  @Az4u2c: the suspension is not very stable at this speed, the road should really be free of traffic and only very wide curves, maybe i will make a video with one minute of topspeed, but i do not want to risk the engine again

                  Comment


                  • #10
                    hello oil cooler?
                    It may not be a Z, but it's still got a turbo...

                    Comment


                    • #11
                      That's 173MPH you're going... It seems to me that it's simply a piston failure issue. They are probably unable to vent the heat needed to sustain that kind of engine speed under heavy load for that long.

                      Are you monitoring charge temperature at the throttle body as well as your EGT? I would bet anything it's going up and up progressively through the run.

                      Coated forged pistons and oil squirters may end up being the solution you're looking for if you plan to run your engine for that long under severe power and inertial load.

                      I have been driving my car at 120mph on the straight traffic free stretched for 30-40 min at a time and have yet to have any issues, but holding that speed I don't even see boost.

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                      • #12
                        yeah, invest in an egt gauge....and if you're on the stock turbo.....you might want to think about a larger backside to reduce TIP, maybe even get another boost gauge to measure exhaust pressure.

                        oil squirters are also another VERY good idea

                        sustained high speeds can have a very detrimental effect on stock equipment

                        ps I saw no profile, but do you have an intercooler?
                        used to have one of the first high horsepower NA to turbo cam'd 7000rpm pavement pounding z31's....now in process of building an LQ9 LS1 6.0L Z31 with all the goodies

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                        • #13
                          my mods are:

                          exhaust 2,75" turboback
                          IC, mid size (from Audi S2)
                          Benz-Injectors
                          Air Filter
                          GT3271
                          Clutch
                          Nistune (i can post the maps if somebody is interested)
                          Fuel Pump+Fuel Filter

                          as you can see still low-cost-tuning.

                          i have an etg and it showed around 970- 1000°C at top speed. I know this is 50° too much, but turbo is still ok, i checked that.

                          I had 20° of timing and AF in the low 10th

                          Oil temp was quite high, i do not exactly how high as i have still only the stock gauge

                          i thought about oilSuirtirs too, a mate of mine compared the VG30DETT and the VG30ET botton end and said that they are more or less the same and he could implement the oil-suirt feature easily just by drilling holes that are already drilled in the DETT-block.

                          Better Pistons maybe goos as well, how much is a set of those.

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                          • #14
                            i'd like to quote OR-Zman

                            there is no cheap performance.

                            thanks

                            Comment


                            • #15
                              oil squiters

                              i mentioned oil squirters twice on z31.com and got no interest. But i am keen to have them and i would gladly contribute to this in whatever way i can.
                              Andrew

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