Saw it happen to another bloke and it was cos his stock injectors were hitting their limit, although his graph plateaued a lot more extreme than yours. Could also be air flow (ie need more boost or bigger turbos :zlove: ). Cheers Rob
What rpm does the power fall on the first peak Niall? Looks like you might need to step the vct back a few rpm.
is that what you think it is? ill get another run done with RPM, as 150kph doesnt mean much. I thought it may have been that the AVCR overshot itself and then reduced the boost. as it does have boost feedback
At 150kmh in 4th gear with a tyre diameter of 26inches it will be doing 4500 rpm. I guessed your tyre size to be 255 40 18, what are they? Do you know where the vct is set, it may need to go up to high 5000's to keep the torque up longer with bigger turbos and heads. I thought it needed to come down as it looks like it happens high in the rpm but that appears not to be the case. Was it ran in 4th or 3rd?
you guessed the tyre size spot on, i dont know where it is set but i could find out. It was run in 4th Could i be right with what i said about boost?
what if i had the duty cylce set higher than desired boost ? so it reduced it one it realised it overboosted?
Avcr wont do that, it reacts alot quicker to boost spikes. I would set the vct to 5900. Any increase in port volume aswell as turbo size will affect the engine ability to consume air. This reduces the torque and requires the ecu to hold the vct longer to enable sufficient air flow at lower air speed. Contrary to what is often thought, boost does not change how an engine works, it changes how it reacts to various conditions.
Nice. thanks for the tips. thats something i would not have seen. so that first lump is with VCT still on, then it goes off where that low spot is?
That the way it looks to me. It cuts out too early resulting in a power loss due to the intake charge not having a high enough volume to fill the cylinders in the reduced time frame after the vct change.
i suppose as an easy way to confirm it i could do back to back runs with the VCT connected and disconnected and see how it looks. cheers
