dmd85059

Oil filter is one of the most important part of the engine but oftentimes overlooked. I've done extensive searchings on the web to find the best filter for my GS300 and have concluded that Amsoil SDF filter is THE ONE.

HERE IS WHY (correct me if I'm wrong!):

Most filters sold out there advertise on "performance" (how well and how small the particles the filter can filter in one pass). Well, in this category, nothing beats the Purolator PureOne with the smallest pore size of 10 microns (Mobil1 smallest pore size is 16 microns and Amsoil is 17 microns. Particles above 20 microns in size are the ones that can cause significant damage). The smallest pore size reflects the smallest particle an oil filter can filter.

So, if we only judge by performance, Purolator PureOne should be the winner right? Wrong! There's another important aspect beside how well a filter can filter, THE FLOW-RATE. Just take a look at all the filters sold out there, none of them would advertise on how well the oil can flow through the filter. Why? Because in order to make a filter that can filter very small particles, they would have to sacrifice flow rate and they wouldn't want you to know that so they kind of ignore it. In terms of flow rate, Mobile1 flows almost twice as much oil as Purolator PureOne and Amsoil can flow almost 3 times more oil than PureOne.

WHY DO WE CARE ABOUT FLOW-RATE?

Well, built in your oil filters is something called the Pressure Relief Valve. This valve will open when your filter is completely plugged or when you floor your car and the oil flows through the filter cannot keep up with the demand of the engine.

So, I hope you can see why flow-rate is important by now. If you drive like a maniac (flooring your car most of the times) and use a filter with restrictive flow-rate such as PureOne or Fram TG series or even Mobil1, the Pressure Relief Valve would open most of the time letting all the dirty oil through. As a result, all the advertisings about oil filter performance become meaningless, YOU'RE RUNNING ON UNFILTERED OIL!

WHY AMSOIL SDF FILTER?

Amsoil SDF filter has the best combination of flow-rate and performance as well as capacity. STP S5 filter also has a very good combination of performance and flow-rate. Mobil1 perfomance is on par with these but has about half the flowrate of Amsoil filter.

Here are my preferences:
Amsoil SDF (17 microns / 13.1 fl-oz per min. on 30W oil)
STP S5 (18 microns / 11.8 fl-oz per min. on 30W oil)
Baldwin (17 microns / 9.1 fl-oz per min. on 30W oil)
Mobil1 (16 micons / 8.1 fl-oz per min. on 30W oil) --> I think this is a bit restrictive in terms of flow-rate.
Lexus genuine filter -- no known specs but looks pretty well built , probably >25 microns and decent flow-rate -- I've been using this until I switched to Amsoil filter.

I now run my car on XL-7500 10W-30 Amsoil and Amsoil SDF filter. Oil is changed every 6k miles and oil filter at every 3k miles. My GS has 50k miles now and still runs as smooth as silk and feels like new.

Reference:
http://www.OilFilterStudy.com

Ditto

If you do a search on this forum, the topic of oil filters is discussed here in depth. It seems that the 90915-2004 is the way to go if you can find one.

I am just wondering who sells AMSOIL Products though. Napa? Autozone?

dmd85059

You can buy Amsoil stuff via their website.

I've just done some more searchings and found this one. Looks pretty darn nice but darn expensive for those of you racers.

http://www.brandsport.com/trd-00642-90915-001.html