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Thread: Fitting vxr injectors & fuel rail on a mark 4 gsi turbo...

  
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    Fitting vxr injectors & fuel rail on a mark 4 gsi turbo...

    Fitted the vxr fuel rail and injectors on my astra gsi mark 4 turbo and the car is running not good...(i.e. was running pokier for a few weeks but now it feels like its restricting when i floor it) ....the car was mapped when it was bog standard by a performance company...not phase chips etc....

    so now the car has vxr injectors and the vxr fuel rail fitted...is the reason for poor performance because the ecu is mapped to standard spec?

    cheers

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    Quote Originally Posted by Loony View Post
    so now the car has vxr injectors and the vxr fuel rail fitted...is the reason for poor performance because the ecu is mapped to standard spec?
    Yes the car needs to be mapped, so it knows what type of injectors are fitted and how to use them correctly.

    While getting it mapped you may as well have the larger VXR AFM fitted and have the map thats suitable for it.

    Welcome to AOC

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    as far as i understand, you need to have the new injectors mapped to the car? or atleast to get the best out of them.

    it could now be getting too much/too little fuel.. cant remember for definate though.

    someone will know
    Regal Phase 3.5,VXR Turbo,VXR AFM,VXR Injectors,Courtenay FMIC,Dbilias Flowmaster,Regal Precat,Miltek exhaust,Lightened Flywheel,Uprated Clutch,Denso Plugs,Veccy Pipe,Eibachs,308mm Discs

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    Isn't it the case that using the LEH injectors on the LET rail is how it should be done?


    But the injectors will deffo need a suitable map to run properly, probably overfuelling, dependant on throttle position, revs etc.
    Get someone to follow you and boot it a bit, see if there's any smoke.

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    yeah, a lot of people use the Leh injectors on the let rail, yet regal told me theres no point and they dont do it.. :s

    but it could now mean you're cars running lean? so probably advisable you get it sorted asap :s
    Regal Phase 3.5,VXR Turbo,VXR AFM,VXR Injectors,Courtenay FMIC,Dbilias Flowmaster,Regal Precat,Miltek exhaust,Lightened Flywheel,Uprated Clutch,Denso Plugs,Veccy Pipe,Eibachs,308mm Discs

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    take them off - put the others back on, take the car to a tuner and fit them again and then get a map.

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    k cheers guys

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    You use the VXR injectors on the Z-LET rail because the Z-LET uses a higher fuel pressure regulator.

    The VXR injectors pass more fuel while they are open than the Z-LET ones do. Therefore if your mapping is for the Z-LET flow rate you'll be adding more fuel than the map expects. The exhause air/fuel sensors will pick up on this and an adjustment will be made, but at times that adjustment will not be enough and you'll all ways be running with the adjustment.
    Tell me what you've done, not what you're going to!

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    The duty cycle on the VXR injectors is different too iirc. Think they are the same impedance but the ECU won't like them being on their.

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    Quote Originally Posted by mattcoupturbo View Post
    The duty cycle on the VXR injectors is different too iirc. Think they are the same impedance but the ECU won't like them being on their.
    Matt, the duty cycle is not dependant on the injector, the ECU controls the pulse width modulation. Hence the need for different software to compensate for the higher flow rate of the VXR injectors.

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