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1KZ-TE Venturi/butterfly plate removal

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  • 1KZ-TE Venturi/butterfly plate removal

    Another modification I’ve been keen to trial for some time. I finally found time to remove venturi and whip out the plate.



    The 1kz has a throttle plate installed in the intake system (actually referred to as a venturi). It shouldn’t be confused with the throttle on a petrol engine which is to control the engine.

    Its function on the 1kz is twofold:

    One – Its major roll is as part of the EGR system, especially at idle where it is used to create manifold vacuum and draw in exhaust gas via the EGR system.

    Two – On engine shut down it fully closes which smooths out the traditional diesel shut down shudder.

    On my Prado I have a couple of issues with it, firstly being stepper motor controlled it’s slow to respond. Coming off idle, low RPM or when backing off between gear changes it give a significant feeling of throttle/turbo lag.
    It also stalls the Turbo as it closes giving significant turbo lag
    Secondly at low speed/low RPM, light throttle driving any slight movement of the accelerator petal causes the plate to open/close which can result in significant drive line backlash.

    So once again using my rig as guinea pig; I’ve removed the plate.

    Potential Pros –

    :arrow: Reduced Turbo lag, especially between gear changes. (Like fitting a blow off valve)
    :arrow: Better off idle response.
    :arrow: Increased low rpm performance and driveability
    :arrow: Potential for a minor fuel economy increase at low RPM/light load cruising.
    :arrow: Reduced light throttle EGT’s
    :arrow: Reduced intercooler heat soak/temperature spike off idle.

    Potential Cons – (there's always some :roll: )

    :arrow: The EGR system will be compromised. (But if you’re doing this mod then the EGR system is probably be blocked/disabled already)
    :arrow: The engine will shut down rough – Like an old school diesel (Yes your wife will notice, and no, she won’t like it :evil: )
    :arrow: In the event of a catastrophic Turbo failure, there is potential for the engine to “run away” - rare but still a risk worth considering (although with a manual vehicle if you catch it early and realise what’s happening you can stall the engine) Remember there are plenty of diesel Turbo engines without plates, including some Toyota motors (1hd-t for example)

    So, in the real world:

    :arrow: Hard to say but I seem to have a smoother idle and slightly easier starting
    :arrow: Much better off idle response and excellent response between gear changes. Turbo lag between gear changes is now all but nonexistent. This gives a very good increase in drivability in a manual vehicle.
    :arrow: Only done just over 50km so Jury’s out on any economy gain (if there even will be any)
    :arrow: Engine shut down is a little rough. Exactly like any diesel without a throttle plate (like anything early/mid 1990’s) it gives a good shudder - very truck like now. Most won’t like this.
    :arrow: Further driving has also shown faster Turbo cool down times, a result of increased idle airflow.


    All in all I’m quite happy with this mod so far. The increase in driveability far outweighs the disadvantages for me.

    Mick
    [CENTER][B][I][SIZE=1][COLOR=blue]1KZ-TE Turbo Diesel, 5 speed manual, 3.5 inch lift, 265/70/17 Mickey Thompson MTZ, D-Tronic chip, Boost controller, mandrel exhaust, dump pipe, modified intake, ARB steel bar, Magnum winch, Safari snorkel, rear drawers, half cargo barrier, dual batteries, Uniden UHF, Sat Nav, reverse camera, Magellan XL , Tjm bash plates, ARB alloy roof rack, rear telescopic work light and numerous other modifications!!!
    Now with 3BAR MAP sensor & 18PSI Boost![/COLOR][/SIZE][/I][/B][/CENTER]

  • #2
    Re: 1KZ-TE Venturi/butterfly plate removal

    Sounds very interesting Mick...

    I will be keen to see how it goes...


    joey
    Featured - issue 140 Australian 4wd Action.
    -issue 52 Modified 4wds .
    Locked ,Lifted, boosted Brut---"Pradzilla".
    [IMG]http://i236.photobucket.com/albums/ff268/bigfryy/_0481154045-2.jpg[/IMG]

    Comment


    • #3
      Re: 1KZ-TE Venturi/butterfly plate removal

      Sounds very interesting Mick...

      I will be keen to see how it goes...

      Lovin it so far Joey

      I think it'll be staying out for good.

      Mick
      [CENTER][B][I][SIZE=1][COLOR=blue]1KZ-TE Turbo Diesel, 5 speed manual, 3.5 inch lift, 265/70/17 Mickey Thompson MTZ, D-Tronic chip, Boost controller, mandrel exhaust, dump pipe, modified intake, ARB steel bar, Magnum winch, Safari snorkel, rear drawers, half cargo barrier, dual batteries, Uniden UHF, Sat Nav, reverse camera, Magellan XL , Tjm bash plates, ARB alloy roof rack, rear telescopic work light and numerous other modifications!!!
      Now with 3BAR MAP sensor & 18PSI Boost![/COLOR][/SIZE][/I][/B][/CENTER]

      Comment


      • #4
        Re: 1KZ-TE Venturi/butterfly plate removal

        Gday Mick
        Interested in this mod, how did you go getting the screws out - did you drill them?

        Cheers

        Adrian
        Silver '04 KZJ120~Manual~GXL~Dobinson/Kings lift~Custom valved Ironmans~Detroit Locker~Endless Air~X9 Superwinch~Madman EMS1~TJM Dual Battery~Rhino Roof Tray~120W solar panel~Foxwing awning~Bushskinz UVP~Long Ranger water tank~Bushman fridge~Steinbauer P-Box~Beaudesert 2 3/4"~Airtec Snorkel~TJM Sliders~Prico Boost Gauge~BFG-KO2s~TPMS~GME TX3420~Front and Rear Cameras~Ultimate Camper hanging off the back!

        Comment


        • #5
          Re: 1KZ-TE Venturi/butterfly plate removal

          I received a PM on this from Adrian - thought I'd post my reply as it may be usefull to others as well.

          Hi Adrian,

          Sorry about the delayed reply (to your post) I'm only on PP occasionally these days.

          I drilled the heads off the screws and then unscrewed them from the opposite side by grabbing the`peened end with needle nosed vice grips.

          They are a standard metric pitch threads and will be easy to source if you want to replace the plate in the future.

          Mick
          [CENTER][B][I][SIZE=1][COLOR=blue]1KZ-TE Turbo Diesel, 5 speed manual, 3.5 inch lift, 265/70/17 Mickey Thompson MTZ, D-Tronic chip, Boost controller, mandrel exhaust, dump pipe, modified intake, ARB steel bar, Magnum winch, Safari snorkel, rear drawers, half cargo barrier, dual batteries, Uniden UHF, Sat Nav, reverse camera, Magellan XL , Tjm bash plates, ARB alloy roof rack, rear telescopic work light and numerous other modifications!!!
          Now with 3BAR MAP sensor & 18PSI Boost![/COLOR][/SIZE][/I][/B][/CENTER]

          Comment


          • #6
            I would like to caution anyone that has done this mod or is thinking of doing it, I know this is a long time after this info was posted by Mick but in my mind the following info is important.

            I carried out the above mod almost 10 years ago to my KZJ120, I still own it and whilst it has done many km since the mod was done without issue I have stumbled on a bit of information in a Denso service manual for the VE5 fuel pump on the 120 1KZ.

            It is true the primary function of the throttle flap on this engine (and the 5L-TE engine sold in other markets) is to create vacuum for the EGR to function, it is also there as a safety measure to shut off the engine in case of the spill control valve sticking closed. If it wasn't there the engine would rev uncontrollably to destruction.

            Anyhoo, I have refitted mine, 2x M4 x 16 philips head countersunk stainless screws is all that's required.


            Click image for larger version

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            Silver '04 KZJ120~Manual~GXL~Dobinson/Kings lift~Custom valved Ironmans~Detroit Locker~Endless Air~X9 Superwinch~Madman EMS1~TJM Dual Battery~Rhino Roof Tray~120W solar panel~Foxwing awning~Bushskinz UVP~Long Ranger water tank~Bushman fridge~Steinbauer P-Box~Beaudesert 2 3/4"~Airtec Snorkel~TJM Sliders~Prico Boost Gauge~BFG-KO2s~TPMS~GME TX3420~Front and Rear Cameras~Ultimate Camper hanging off the back!

            Comment

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