Oil filter revisited
 

Many moons ago it was discovered that the Purolator L30165 (and equivalents) was an oversized but direct fit replacement for the Purolator L14459 (and equivalents). The L30165 is indeed a direct fit and it does indeed have a larger surface area and filtering capacity. However, today I stumbled upon a large difference. While both filters have bypass valves, the L14459 has a bypass pressure of 12-15psi while the L30165 has a bypass pressure of 25-35psi!!!!!

The obvious concern is that the larger L30165 filter will not go into bypass and could become a large resistance to flow at high RPMs. The concern would obviously be greater as the filter gets filled up with particles over time.

Anyone want to add some thoughts or insights to this?

Re: Oil filter revisited
 

Surprised no one is concerned about this.

Some good news. The purolator L20073 is the same size as the L30165 but has a bypass pressure of 12-15psi. The bad news is that there is no high quality equivalent (PureOne, Bosch Premium, M1, K&N, etc.) of this model. But if you want a basic yet good filter with the right BPV, this would work.

Other good news, Royal Purple (10-2808) and Purolator (PSL14459) sell L14459 equivalents with synthetic media. These have great filtering and high capacity for extended oil change intervals. And, of course, the correct BPV pressure. I will probably switch to one of them on the next oil change. The best news is that these can also be used on my Tribeca and the new Acura. One filter for all three cars!!!

Re: Oil filter revisited
 

Tony, nice find!:)
I really liked the Purolator filters in general, and the sheer size of the L30165 had to help (lower pressure loss/more flow/a bigger garbage can for the crap).
Having a long history of modding stuff, AND changing oil at reasonable intervals, I was very pleased with the L301645 UNTILL they trippled the price.:rolleyes:

After doing my oil pump mods, and installing an under hood mechanical oil pressure gauge I am not worried about the L30165, BUT appreciate the info.
I just called Advance Auto and they say its (L20073) like $4.00!:eek:

COOL!:cool:
Thanks Tony!

Re: Oil filter revisited
 

The Fram Ultra oil filter has very good reviews at BITOG. After years of making poorly regarded filters, they must have improved. The XG3593 with synthetic media fits our cars.

Re: Oil filter revisited
 

The software that I use for work says that the Bosch 72160 is a direct replacement for the purolator L20073. I'm not sure if that's correct or not, but that's what it says.

Re: Oil filter revisited
 

MANN makes some very high quality filters for a lot of different makes, they should have something to fit our needs.

Re: Oil filter revisited
 

They are indeed good at filtering but their flow resistance is among the highest. You won't be able to push a lot of oil through them before they go into bypass. The Purolator P1 has just as good filtering but slightly better flow. Also, the XG3593 is not an oversized filter. We have lots of options for direct (non-oversized) replacements which are also premium filters (Purolator P1, Mobil 1, Purolator Synthetic, Royal Purple, Amsoil and so on).

Speaking of which, the Bosch that Mike mentions is not easy to find and is not the Bosch Premium. For standard oversized filters, we can just get the standard Purolator. We just can't get the oversized L20073 in a premium version like the Purolator P1 or the Bosch Premium. We can get the old L30165 in a premium format from Bosch, as noted in my signature, but apparently that filter has the high bypass pressure as well. More on that later...

Re: Oil filter revisited
 

Just the man I need. Where in the oil path was your gauge located? Can you describe the oil path in a simplified way like:

Pump -> Filter -> Gauge -> Engine Passages

I was exchanging posts with a guy on the Acura forum that claimed the bypass pressure may not matter. His reasoning was that the oil pump is positive displacement and will push the desired flow regardless of the flow resistance in the path. It will just result in higher pump pressure. I can see that, to an extent. But every pump is limited in the pressure it can generate. I just don't know if we are anywhere near that limit.

It helps to assume flow rate and pressure are linearly related for both the filter and the engine passages. That isn't exactly true but it is close enough for now. I have no feel for the "resistance" or the engine which is to say the pressure divided by the flow rate. (psi/gpm) Any idea on that...assuming normal operating temperature? Also do you have an idea of the oil pump's typical flow rate as a function of RPMs...also at normal operating temperatures? We can get the filter resistance from the datasheets, I think. Together, we could estimate at what RPMs the filter will go into bypass.

But if our pump can generate the necessary pressure to push the desired flow through both the filter and the engine at redline, maybe we don't even need to worry about the bypass pressure. In fact, a high bypass pressure would even be desirable since the oil will remain filtered at all times. Then the question would be, do we need it filtered at all times? I mean, how fast does an engine get exposed to particles that need to be filtered anyways? Maybe the time it spends near idle is enough time to filter most of the particles out. Having to pump a high flow rate through a high pressure will consume energy. That means less HP and poorer MPGs.

Filters are one giant engineering tradeoff. High efficiency versus high flow. More time filtering versus less energy required to pump. And then you have overlap. High efficiency versus less energy required to pump.

Do modern engines use filters with lower bypass pressures because their pumps have limited pressure and they want to maintain high flow at high RPMs or do they use them to conserve energy by limiting flow resistance and, hence, pressure, at high RPMs and high flow?

And to make it even more complicated, the oil viscosity will have an effect. The thicker the oil, the more resistant to flow the filter and engine will be and the higher the pressures will get. I was SHOCKED to find that Acura suggests 0W20 oil for the TL. Many people assumed that was to improve gas mileage to meet CAFE standards and that they weren't overly concerned about the impact of super thin oil on engine wear since their engines will easily get past the warranty period. Also, most people use synthetics on those cars and synthetics do tend to be thicker at normal operating temperature and also tend to shear less under high stress (high RPMs). Still, my gut tells me to run 30 weight oil and take the 0.5 MPG hit.

Re: Oil filter revisited
 

T fitting at the stock oil pressure sensor location.

Re: Oil filter revisited
 

Tony, back in January did we do the oil pump mod?

Re: Oil filter revisited
 

I have seen discussion on going into bypass on the NASIOC forums, but can not find it juts now...... The small four cyl filter was too small for high revving engines with increased pump capacity.

If your engine is clean and ok and oil (+filter) changes frequent, I do not think the higher by pass pressure is a problem.

BTW, after I did the HG job and cleaned the engine internals the oil looks still clear as new after 2000 miles.



Cheers,

Tapani

Re: Oil filter revisited
 

Yes, you did. And I swear the engine temp has run lower since. It would make sense that this would improve flow significantly by allowing more pressure to be available at the pump outlet.

Any idea where that "T" sits in the system? Before or after the pump? Before or after the filter? Before or after the engine? You get the idea....

Re: Oil filter revisited
 

Between the pump and oil galleries.

Re: Oil filter revisited
 

So it's an art exhibit, is it?:lol:

OK, now where is the filter in this system? Between the pump and the gauge? Between the gauge and the galleria? Between the galleria and the pump?

On an aside, I read another person claim that the bypass is mainly there to protect the filter from blowing. I don't personally buy that but I figured I would throw it out there.

I am trying to gather as much information as I can on these newer filters from Royal Purple, Amsoil and Purolator. They all claim to filter better, flow better and have long service life (high capacity). Of course, they are also insanely expensive. If Tom if freaking out over the purolator price, he would going into full shock if he had to buy one of these suckers! But if all their claims are true, they would truly enable long OCIs with premium oils like Redline and Amsoil. Then the price isn't as bad. However, the one claim I am most skeptical about if the long service life. The surface area in these filters is actually lower than in, say, a similar Purolator P1.

One of the best/newest studies I have found:

http://forums.evolutionm.net/evo-eng...63t-4b11t.html

But he mostly focused on filtering and not flow or capacity.

Re: Oil filter revisited
 

Oil pan

Oil strainer

Oil pump rotor-Relief valve

Oil filter-Bypass valve

Cylinder block right hand main gallery

Oil pressurs switch-*-journal1-journal5-journal6-journal7-cylindar head RH cylindar block LH main gallery

Journal2-journal3-journal4-cylindar head LH




The * is the position of the mechanical oil pressure gauge.
Can I go back to sleep now?:o


FSM, Sections 2&3, Lubrication2-4 Page3