I'm finally getting a boost gauge. I like the Autometer Nexus but they offer two kinds. One for boost and one for boost and vacuum. I'm getting the boost gauge but was wondering what the boost/vacuum gauge is for? Does anyone have any Nexus gauges? I have a downpipe and K&N air filter. Would love to get a RB CB. Thanks, Rick

 

this is not exactly the correct terminology use here, but basically a boost only gauge only measures positive manifold pressure. the boost/vacuum gauge will measure positive(boost) and negative(vacuum) pressure. vacuum is good to know because it will tell you if you have a leak somewhere. also more vacuum you have at idle the healthier your engine is(sort of).

 

Check this thread:

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/vacuum-gauge-what-can-tell-you-731692/

 

Thanks guys.