Originally Posted By: wtd
It seems like someone on here actually found a way to test the different filters for pressures and flow and posted that the UPF filters were more restrictive than the regular Delco filters. I may be wrong but I do remember I quit using these filters after this. I think I still have about nine UPF52 filters. I also still have one or two PF52 equivalant Hard driver filters that I got years ago. I tried one on my 93 S-10 4x4 that I had at the time and it leaked all over. For some reason it didn't seal well to the remote oil filter adapter. Wayne
I believe the data from ACDelco before I'd believe someone in their garage trying to make scientific measurements. If someone did an accurate job of showing that the Ultraguard was restrictive, I never saw it. Do you have a link to this data?
I was in the heat of that whole "the Ultraguard is restrictive" rumor on the Vette boards a while back (its been maybe 3~4 years now). I emailed ACDelco engineers with the a link to the very long thread on the Vette boards and they basically said there was obviously something wrong with the "independent data".
I've also ran WIX, NAPA Gold, Amsoil and ACDelco Ultraguard oil filters on my Z06 (alwasys with Mobil1 5w-30) and the oil pressure reading was exactly the same with every one of these filters. If the Ultraguard was so restrictive, the oil pressure would have been noticeably higher ... but it certainly wasn't in my case.
