After I installed the BC, there is still a slight spike but not as much anymore. With the boost set to 1.35bar, the spike is only up to 1.4bar. You will only see the spike with the Defis. The EVC will show you peak reading but where it "holds" and not where it peaks. So, if I set boost to 1.35bar, Peak Hold (PH) will show 1.35bar, +/- 0.1bar. Actually, you set the boost based on your PH readings. If you want to set to 1.5bar, then when setting, you should adjust the dial untill you see PH at 1.5bar... sounds confusing kah?? Well, its not that complicated. You may have to make a couple of runs before you get the required settings.