Dyno runs done prior to any mods are also known as 'baseline' figures. When testing after a mod, then you know exactly how much impact that particular mod had. e.. Test your brand new car at 360rhp. Add a mod, dyno again. Figure is now 365rwhp. You now know that particular mod was worth 5 rwhp. without the baseline, you won't know how much, if any, gains were made with that mod.Vetteless said:so why do some people dyno there car like 500 miles after they get it....shouldn't they wait till they do a mod or is every vette a little different