Having mucked about for years trying to get the boost properly controllable using a series of Cosworth Actuators and manual bleed valves - I finally decided that I wanted it right, at any cost.

Two things had to happen, the baseline boost had to be steady, and then there had to be variable control with RPM. The latter is discussed later in the Blitz ID section, but the former, the baseline boost is addressed here.

Having decided on a spring rate , I took a trip with Don Norchi from Kalmar-union to see the good people at Forge Motorsport who custom built me an actuator while I waited.

Because the new actuator did not come with the complex bracket arrangement required to fit the Volvo turbo, I simply cut the bracket away from an old 850 actuator and drilled it to accept the Forge unit. The actuator rod length was left long by Forge so that I could cut it to length to suit when fitted to the car.

The photo above shows the edited bracket ready to accept the Forge Actuator. I gave it a coat of high-temp black paint before final fitting so that it would not rust and look nice! If you want to obtain a bracket like this without all the grinding & painting work, you can purchase one pre-made from Kalmar Union.

The new actuator came with plenty of thread so that I could trim to length. Note the yellow sticker, this is an indication of the spring rate. Forge have ranges denoted by a colour code system so that you can easily identify a certain spring rate unit. I chose 0.7bar as my experimentation had showed that any more would cause boost spikes low down, and I am using the SBD-ID to control top end boost anyway.

You can see the actuator fitted here - the induction pipework and turbo heatshield have been removed to allow easy access. The blue rag is stuffed in the turbo inlet to stop me dropping anything in there!

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