I was trying to use my phone to respond, apologies. Warp is describing another test method, which is also used and needs an eddy current system ( or similar). A sweep test is where one sets the dyno to do a loaded run, from say 1500 rpm to 7000rpm pausing at 250rpm increments( or one of the operators choosing) for a portion of a second, to log AF ( or boost or whatever). I find it very useful for exacting ign adjustments. Most folk who insist on a PCV for tuning do so because they can use the Tuning Link software, which automates fuelling adjustments to a large degree. It is quite fast. Probably do a rocket fuel map pretty close in 30 mins. Personally , I used it for a while ( obviously with DJ/PCV products) , we had to pay a lease fee for the software each year. When I first payed our $ was roughly 60C US. After some years our $ was 105c US and I asked them for a re-adjustment of the lease fee, especially because the software was unchanged and our $ was worth twice as much. They said no, tuff luck,.... so I suggested they fit the lease fit into one of their bodily apertures, never paid it since. I get much better numbers anyway. The TL process is a sort of averaging process, so if one wants an average fuel tune, then go for it. I like to get it exact. Well to my exact , anyway.