Originally Posted by nghiaho58
How come there is no boost gauge on the supercharge engine car (S5 but almost every turbo charge engine car has one? Just curious. Actually, it was my wife question since she has a RDX 2.0 Turbo.
Boost gauges are more important and useful for Turbo-charged engines than supercharged engine because of the nature of how they generate the compressed air for the engine to use.
Turbochargers uses the exhaust of the engine to compress air which requires a more complicated and elaborate inlet systems. More parts also means that there are more connecting areas that can lead to leaks which can lead to overboost thus results in turbocharger and engine failure. In addition, the power delivery of turbocharged engines are not as linear as supercharged engines, especially in the older days and on a race track. It is very important for a driver to know when the boost is going to kick in and when to back off on the boost.
Boost gauges are more of a novelty on today's road cars, regardless if the engine is turbocharged or supercharged. Cool to have but not really necessary, especially when everything is controlled electronically these days.