That's a good question. I don't work for Fram, but I'm sure there's got to be some kind of reason behind it.
Having said that, a little digging tells me that the 9100 line is basically the larger equivalent to that filter (1qt capacity compared to 1/2qt for the 8873), and Fram does make an Ultra in the 9100:
Originally Posted By: John_Conrad
thanks nate.
my bad(memory!). anyhow, isn't royal purple filter supposed to be slightly better than mobil1 and k&n synthetic media fitlers?
Have a look at the Royal Purple filter that has been cut open in this thread:
they don't make an ultra 8873 and i can't get my question answered whether the relief valve setting on the xg9100 of 9-15 psi would be a bad thing, when the ph8873 has no relief valve setting, so that i could try a larger filter
therefore i am left with the standard size royal purple as my only choice, as i perceive it to be better than the k&n and the mobile 1 synthetics.
Originally Posted By: John_Conrad
they don't make an ultra 8873 and i can't get my question answered whether the relief valve setting on the xg9100 of 9-15 psi would be a bad thing, when the ph8873 has no relief valve setting, so that i could try a larger filter
therefore i am left with the standard size royal purple as my only choice, as i perceive it to be better than the k&n and the mobile 1 synthetics.