A good explanation here why the manual boost controller make the turbo spools up feel so aggressive vs the standard factory controller.
If the relief valve is placed in the turbo to waste-gate actuator pipe it acts as a boost controller. The relief valve can be adjusted to give the desired boost pressure by simply adjusting the spring pressure. This is done by lengthening (lower the boost) or shortening (increasing the boost) the relief valve. One of the excellent characteristics of a relief valve is the way the boost is controlled. Due to the way the relief valve ‘cracks’ open once the spring pressure has been reached – no air is acting on the waste-gate actuator until this time. This means that the boost is much more aggressive and rises much more quickly than a turbo car without a relief valve. This is because normally a waste-gate actuator actually starts to open the waste-gate at very low boost levels, gradually opening wider as boost rises until it is fully open – at which point maximum boost has been reached. This has the effect of smoothing the boost all the way until maximum boost is reached. Since a relief valve prevents air getting to the wast-gate until the preset boost level is reached maximum boost is reached more quickly making for a more exciting launch. |
