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Minor engine upgrade in progress.

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  • Minor engine upgrade in progress.


    I've installed a 66 mm supercharger pulley instead of the old 75 mm. I have no idea what this will do to boost. I currently get 4.5 psi of boost, and will not be worried about knocking until I hit about 9 psi.

    I'll dial back ignition a degree or two in high boost areas above 4000 RPM to be on the safe side. There is apparently a quite advanced knock detection system in place in my T6 ECU, which would allow me to set a more aggressive timing map without worrying about blowing the engine. I will start to look into that one as well.

    New plugs (stock specifications) are going in just beacuse I think it is time.

    New injectors (I forget their capcitity) have been installed since the old ones were maxing out during transient fueling at high RPM/high load situations. This means that the entire fuel map must come down accordingly.

    I currently run 45 psi fuel pressure. Brad has reported a pressure loss in his system during high load. I will check if I have the same problem. (I have a fuel pressure sensor installed and hooked up to the T6.)

    Tomorrow I may go for a ride with full logging on the ECU to start figuring out the new numbers.

    A carbon fibre aeroscreen with three rearview mirrors on sexy litle stalks from Richard In France will arrive the day after tomorrow.

    This definetly increases the look of the car, but more or less mandates a helmet when driving. I am unsure of the outcome of this one...

    I am starting to survey different sidepipe exhaust options (together with Brad) since the current catalytic converter is probably becoming a major restrictor.

    I'll keep you posted.

    /Magnus F.

  • #2
    I've now spent a happy hour with a friend mapping out the engine.

    The good news: 8.3 PSI of boost at about 5000-5500 RPM. I will probably see 9 [email protected] RPM. There is a very noticable increase in midrange torque since the blower comes on much earlier.
    You can even hear it meow when you rev the throttle from idle.

    The bad news: Even the new injectors max out, giving me a dangerously lean 0.93 mixture at full boost above 5500 RPM.

    The fuel pressure drops from 52 PSI to 47 PSI during max run.

    A part of this problem may be that the fuel regulator is not of a mainfold air pressure sensing type. In theory it should add 8.3 PSI of boost on top of 52 PSI to offset the boost generated by the supercharger on the other side of the injector. Either that, or the fuel pump cannot give anymore. Brad, I feel your pain right now.

    I'm now off to find a MAP-sensing regulator to see if that cures my problem.

    More $$$.

    /Magnus F.