TRD V8 Supercharger only 6psi?

[crushu]

I have fitted a TRD supercharger to my LX470. We have used an Xede ecu, and have not connected the little valve for the Boost Actuator, and have a vacuum line going to the top of the actuator, holding it where it is.

Boost with the air box intact rises to 5psi, then falls away. Boost with the air box open to atmosphere, goes straight to 6psi, and stays there all the way to top power. That shows that it isn't a blower speed problem, nor a leaking gasket, nor an intake restriction, as either problem would cause the boost to rise and fall, like it did with the intake assembled.

What is holding it at 6psi max?

Thanks

[Gadget@URD]

The TRD Supercharger is a postive displacement supercharger. The impellers are turned at a fixed ratio to engine speed. Under ideal conditions the boost should remain constant at the same throttle position.

When your airbox was closed the loss of manifold pressure shows that the airbox was becoming restrictive as airflow increases.

Gadget

[crushu]

Yeah, I know the box is a restriction, as it goes upto 5psi, then almost straight away, falls off.

The question is why does it go straight to 6psi, and stay there, (with box open) and not continue to rise with engine revs?

[Gadget@URD]

Because is should not with a postitive displacement supercharger. Boost should always be the same at the same throttle position.

Gadget