The big filter doesn't cause the increased oil pressure it is part of the cure. My oil bypass is blocked (on purpose) which means at cold temperatures the oil pressure is very high; even at idle. If you were to jump on it before the oil warms up, the pressure increases even more, you will collapse the filter media. The bigger the filter the less likely this will happen. That is why I stated if you have your bypass plugged, you need a bigger filter. If the bypass is operating as normal the small filter will be fine under these conditions because most of the oil wil bypass the filter.