Oil Filter Experts
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Joined: Nov 2000
Posts: 4,419
Likes: 6
From: Arroyo Grande CA
Originally Posted by Shylor
Can anyone explain why the PF46 oil filter for the Corvette needs an anti-drainback valve? I keep hearing it has one but I don't it a new one I bought. I don't understand why a vertically mounted filter needs this feature.
Safety Car
Joined: Nov 2000
Posts: 4,419
Likes: 6
From: Arroyo Grande CA
Originally Posted by Shylor
Can anyone explain why the PF46 oil filter for the Corvette needs an anti-drainback valve? I keep hearing it has one but I don't it a new one I bought. I don't understand why a vertically mounted filter needs this feature.
Maybe not all of these applications are vertical. And you do want the filter to be full of oil at start-up.
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Joined: Nov 2000
Posts: 4,419
Likes: 6
From: Arroyo Grande CA
Originally Posted by Shylor
I'm wondering why GM went to a smaller filter size with the PF46 (PF44 and UPF44), over the PF52 (of the C4). Doesn't the shorter length means less media area to filter oil? I don't believe the clearance excuse because GM could have just designed in the filter placement higher.
By using less media filtering area does this mean GM feels the PF52 is overkill for the Corvette V8? How much smaller can they go? Why not just use 2 smaller filters then?
Or do the newer engines just run cleaner and don't need bigger filters anymore? Why not just eliminate the oil filter and just change the oil even sooner?
By using less media filtering area does this mean GM feels the PF52 is overkill for the Corvette V8? How much smaller can they go? Why not just use 2 smaller filters then?
Or do the newer engines just run cleaner and don't need bigger filters anymore? Why not just eliminate the oil filter and just change the oil even sooner?
You would probably really have problems with the PF52 if you lowered your Vette below stock.
Thread Starter
Le Mans Master
Joined: Nov 2001
Posts: 6,984
Likes: 0
From: Central Coast CA
Thanks 2KFRC5, now I understand. I didn't realize the PF46 filter was used for other vehicles besides the Corvette. I also wasn't aware the PF46 has been around since 1975. I thought it just came out to replace the PF44.
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Joined: Nov 2000
Posts: 4,419
Likes: 6
From: Arroyo Grande CA
I don't know if the PF46 has been around since '75, it just fits some applications that go back that far. It may very well be a recently designed filter that, maybe, replaces several other filters that have been discontinued, like the PF44.
Don
Don
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Joined: Jan 2005
Posts: 3,675
Likes: 58
From: Hayward (Bay Area) CA
Originally Posted by blkvett01
The Mobil 1 High Efficiency Oil Filter is the most advanced oil filter available for consumers today, offering unsurpassed filter durability and exceptional filtration capability. When used with Mobil 1 Synthetic Engine Oil, this filter provides the ultimate in engine wear and cleanliness protection. Removes more contaminants via a substantial improvement in multiple pass filter efficiency (95% vs. 80% for conventional filters) by using a synthetic fiber media.
What do you think of the K&N Oil filter used with Mobil1 Oil? I'm trying to compare Mobil1 oil filter with K&N oil filter. Any ideas? I'd want the Best overall oil filter! Both Mobil1 and K&N have good reputation.
With our high flow pumps we can handle more micron filteration than past cars. The psi on these car can hit 80 psi or better.
What do you think of the K&N Oil filter used with Mobil1 Oil? I'm trying to compare Mobil1 oil filter with K&N oil filter. Any ideas? I'd want the Best overall oil filter! Both Mobil1 and K&N have good reputation.
With our high flow pumps we can handle more micron filteration than past cars. The psi on these car can hit 80 psi or better.
Thanks...
Racer
Joined: Apr 2004
Posts: 391
Likes: 7
From: Garland Texas
One on the oil filter both are great filters. plus the pf44 & pf46 are good filter. 
I went with the mobil 1 due to the synthetic fiber media i found it to be the best. 
But that is just my 2 cents.
On psi i am not sure i have had two motors in my car the ls1 and now the ls6 and both have hit 80 psi when i push the rpm up. The one on my ls6 is ported but is dose not seem that much better than the one on the ls1 i had. But in some case in traffic i have went down to 20 psi and the engineering specks say that is normal for this type oil pumps. I have used K&N and pf44 and now the mobil 1 and the oil pressure has been about the same so i do not think this could have anything to do with the pressure you have.
Maybe Evil will chime in and help you out there he knows alot.
I went with the mobil 1 due to the synthetic fiber media i found it to be the best. But that is just my 2 cents.On psi i am not sure i have had two motors in my car the ls1 and now the ls6 and both have hit 80 psi when i push the rpm up. The one on my ls6 is ported but is dose not seem that much better than the one on the ls1 i had. But in some case in traffic i have went down to 20 psi and the engineering specks say that is normal for this type oil pumps. I have used K&N and pf44 and now the mobil 1 and the oil pressure has been about the same so i do not think this could have anything to do with the pressure you have.
Maybe Evil will chime in and help you out there he knows alot.
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Pro
Joined: Apr 2002
Posts: 726
Likes: 2
From: Denver CO
Originally Posted by Shylor
How is oil supposed to drain backwards through the filter when the oil filter is vertical and at a low point?
The oil that backflows through the filter originates above the filter. The oil is pumped from the pan, pushed through the filter and then into the oiling circuit. Some of that oil is pushed "up" above the level of the filter. Due to static pressure created by gravity acting on the oil that's higher than the filter, the oil will want to flow down, i.e., backflow, through the filter.
A simple, similar analogy is water drawn through a straw in a glass. Stop drinking and the water will flow back through the straw down into the glass. Put a check valve at the bottom of the straw, and the straw will stay filled when drinking stops.
The check valve (backflow preventer) ensures that the oil galleries remain full and oil will be available to the valve lifters, cam, etc. very soon after startup, instead of having to fill the oil galleries before getting up there.
