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Rod or Injector?

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  • Rod or Injector?

    Hi all.

    I'm in South Africa, and I've just bought a brand new 2010 spec Corsa OPC (you call it Vauxall VXR) in Arden Blue - its the only colour available.

    Anyway, I wanted to have the car mapped, and been doing as much research as I can. Basically what I've picked up from this site is one Tuner blames the injectors for the Piston 4 problem, while another says thats rubbish and back it up with dyno video's etc...

    Anyway I went to visit a well renowned tuner here (who is actually linked to one of the UK tuners). And he said he wouldn't map my car.

    I asked if it is because of the injectors being too small, as I'd be willing to buy larger ones. He said that was all a load of rubbish, and the problem is not the injectors but the conrods - which bend and the pistons hit the cylinder walls causing them to crack (not melt - which would be the case it it was running lean form "undersized" injectors).

    Now he makes a good point, as the failures I've read about have been cracked Piston 4, not melted. (And not even exclusively piston 4)

    But I've also read about, some cars on standard internals running 280-300BHP?

    So, what is the problem, INJECTORS or RODS?

  • #2
    The problem is largely abuse of the engine. The pistons crack under thermo shock from heat too quick, often caused by booting the car without it being warmed up and all parts lubricated (or atleast thats what ive gathered).

    Many people say that standard internals are good to about 250bhp, others as you state are running 280 & 300 on standards. If your worried, upgrade them lol

    http://www.vxronline.co.uk/forum/sho...d.php?t=100344

    See what you think of the linky above, might help with a few things
    Originally posted by Bobbyp90
    Yes Tom! You're a freaking genius!
    sigpic
    Corsa "user guide" , VXR Car Game
    South East Regional Organiser

    PSN: TomFL12

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    • #3
      Ok, so I've done a bit more research on this.
      It's not the melting of the pistons (from injectors being too small)
      or the rods (from over-boost),
      but the failure of the ring skirts - the pistons gudgeon pins are not aligned/centered well, and the pistons "rock" with the skirts hitting the cylinder bores, breaking part of the skirt off.

      See pic below: (Regal's website)



      From a local tuner here, he has seen this in 23 Corsa's, and not exclusively "Piston 4"

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      • #4
        23 Corsa's where mate?

        It has previously been put down to thermoshock so a new view would be an interesting read
        Originally posted by Bobbyp90
        Yes Tom! You're a freaking genius!
        sigpic
        Corsa "user guide" , VXR Car Game
        South East Regional Organiser

        PSN: TomFL12

        Comment


        • #5
          sorry but if the pistons "rock" with the skirts hitting the cylinder bores,the bit would make a bloody big mess as it hit then hit again,plus it would not be to the side of the piston to go.(all the bores have been ok)also on the other pistons the bit is only bewteen the rings,with both rings being ok.

          piston #4 is thermoshock.
          Last edited by wayne/VXR; 12 August 2010, 03:35 PM.
          sigpic

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          • #6
            Surely the thermo-shock would affect the crown off the piston?

            The tuner here did seem to think the rods and pistons are weak. I had just read somewhere about the pins not being center. He did say in the 23 he had heard of, it was not exclusively piston 4.

            I'm just nervous to map as no tuners here offer a warranty.

            Comment


            • #7
              Originally posted by carlo_sg View Post
              Surely the thermo-shock would affect the crown off the piston?

              The tuner here did seem to think the rods and pistons are weak. I had just read somewhere about the pins not being center. He did say in the 23 he had heard of, it was not exclusively piston 4.

              I'm just nervous to map as no tuners here offer a warranty.
              Where are you Carlo?

              And no warranty = if things go wrong! lol
              Originally posted by Bobbyp90
              Yes Tom! You're a freaking genius!
              sigpic
              Corsa "user guide" , VXR Car Game
              South East Regional Organiser

              PSN: TomFL12

              Comment


              • #8
                Well im running round about 250-260 and had no problems at all, theres people running 280 even 300bhp on standard internals!
                Corsa Has Left The Building

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                • #9
                  Im abit hesitant myself about all the mapping..? Although I did speak to a local, well renowned tunner who had no problems with tunning the corsa's. What he did say is to stay clear on the hand held units as they are generic and not suited to your car's individual set-up.?

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                  • #10
                    dont all the main tuners use hand held? tms, regal ect??

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                    • #11
                      Originally posted by Tom_Y2K4 View Post
                      Where are you Carlo?

                      And no warranty = if things go wrong! lol
                      I'm in Cape Town, South Africa

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                      • #12
                        I think most of the dealers do.? It was just the tunning ws saying its far better getting a custom map made for you'r car?

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