The wastegate opens when the boost surpasses its setting. It's a valve an spring holding closed a bypass to the exhaust. So if you over-boost, the WG opens. There is a WG duty cycle you can view (well I can in RomRaider) it shows what % is necessary to keep it close.Always spinning, yes. But then there's the wastegate, which eliminates boost/higher fuel consumption, no? I'm still learning about turbos...
Thanks! If I had just thought that through a little more... Duh.The wastegate opens when the boost surpasses its setting. It's a valve an spring holding closed a bypass to the exhaust. So if you over-boost, the WG opens. There is a WG duty cycle you can view (well I can in RomRaider) it shows what % is necessary to keep it close.
At low RPMs, the turbo acts as an extra load on the engine as the exhaust gasses keep it spinning without producing extra pressure or power. As the RPMs climb, the vacuum reduces and then goes into boost where the increased pressure and power produces a net positive amount of power. Somewhere early in that rapid transition is a brief moment of “zero boost” where the turbo neither robs power away, nor does it produce extra power if compared to a naturally aspirated version of the identical engine. That point is roughly where the driver feels the turbo lag end and the rush of the turbo boost.So, when is there 0 boost at all, if ever?
No.Someone please correct me if I’m wrong. I am by no means an engineer or expert.
How I understand it is the intake side of the turbo is always spinning when the engine is running and producing some positive pressure to the intake. However at low revs, this positive pressure is negligible in the presence of the vacuum the pistons produce. As the turbo spools up, the pressure increases (boost) to produce a net increase in power. Therefore the only time the turbo is at complete zero boost is when it is not spinning, or engine off.