What is turbo lag (and how do I avoid it)?
The majority of turbochargers feature a wastegate–a valve which allows some of the exhaust gas to be directed around the turbine. This allows the turbo’s shaft to spin at a reduced speed, promoting increased turbo life (among other things). Think of it as a ‘stand by’ mode. Since the turbo isn’t needed during relaxed driving anyway, this effect is harmless… …until you suddenly want to accelerate. Let’s say that you are loafing along, engine spinning 1500 rpm or so. You instantly floor the throttle. The exhaust gas flows through the turbo and cause it to spool (spin up to speed and create boost). However, at this engine speed there isn’t very much exhaust gas coming out. Worse still, the turbo needs to really get spinning to create a lot of boost. (Some turbos will spin at 150,000 rpm and beyond!) So you, the driver, need to wait for engine revs to raise and create enough exhaust gas flow to spool the turbo. This wait time–the period between hitting the throttle at low engine spee
