Mini-update bypass test
- Thread starter Gary Allan
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Okay ..okay ...I was holding off on the progress and I wanted to ponder some things before posting ..but here goes...
We're seeing something new here with the 5w-20. Upon start up we're getting an initial 10 psid that quickly erodes to the standard 4 psid. It doesn't get anywhere near the pressure relief of 82 psi ..but the engine side is lower by a solid 10 psi.
Since PSID is the same shortly after warm up we may conclude that this isn't a function of filter accumulation (note the "may"). It has been suggested that the 5w-20 flows "easier" through the engine ..so much so that it's not so much that the filter presents any more resistance ..but the engine so much less at that given volume. The transition, as with all others, is brief. I really was tempted to swap it out to see if the same thing happened with heavier oil ...just to eliminate the filter as the cause ..but I'm commited to keeping his fill in for 5k to allow real particle production in a "real"-like setting. This happened very shortly after the swap from the 20w-50 (about 400 miles or so)..so we have lots of possibilities ...disruptions of established films (tribute to 1sttruck
) and other seating/transitional behaviors ...different chemistry ..this is the first Semi Synthetic that's been in the engine for probably a decade...
I'd snap a shot of the guages ..but my daughter has the van up at college to bring back her stuff for the summer. She's there a little later than the normal student body since they have one more consolation game in the post season. I'm tracking fuel economy closely here...so I just advised her to record the fuel added on the log and to leave the trip odometer alone. So far ..this thing is doing better than it ever did in new condition. I expect this to change when short trips dominate its usage over the summer and viscosity will prove to have more of an impact on fuel economy.
We should be at the 3k mark very shortly ..so this should give us some inkling to the practical longevity of this tiny filter from here on out.
We're seeing something new here with the 5w-20. Upon start up we're getting an initial 10 psid that quickly erodes to the standard 4 psid. It doesn't get anywhere near the pressure relief of 82 psi ..but the engine side is lower by a solid 10 psi.
Since PSID is the same shortly after warm up we may conclude that this isn't a function of filter accumulation (note the "may"). It has been suggested that the 5w-20 flows "easier" through the engine ..so much so that it's not so much that the filter presents any more resistance ..but the engine so much less at that given volume. The transition, as with all others, is brief. I really was tempted to swap it out to see if the same thing happened with heavier oil ...just to eliminate the filter as the cause ..but I'm commited to keeping his fill in for 5k to allow real particle production in a "real"-like setting. This happened very shortly after the swap from the 20w-50 (about 400 miles or so)..so we have lots of possibilities ...disruptions of established films (tribute to 1sttruck
I'd snap a shot of the guages ..but my daughter has the van up at college to bring back her stuff for the summer. She's there a little later than the normal student body since they have one more consolation game in the post season. I'm tracking fuel economy closely here...so I just advised her to record the fuel added on the log and to leave the trip odometer alone. So far ..this thing is doing better than it ever did in new condition. I expect this to change when short trips dominate its usage over the summer and viscosity will prove to have more of an impact on fuel economy.
We should be at the 3k mark very shortly ..so this should give us some inkling to the practical longevity of this tiny filter from here on out.
Isn't that expected? Thinner oil, less resistance through the filter, less resistance through the engine.
I went to visit a vendor over the last couple days. The guy had a 0-10 PSID differential pressure gauge sitting on his desk. I was drooling over it, in the end I felt it would be rude to ask for it. (Industrial quality gauge, about $200)
The range was a bit low, but it would have been great for getting some accurate readings for filter loading.
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Well, yes ..sorta. But in this case we see higher initial resistance in the filter. That is, at the same (assumed the same minus any clearance losses that may be minor) volume ..imperical data shows that filter resistance is all but transparent (3-4 PSID) in heavier viscosities. The difference in visc between the visc of the former oil used (10w-30 thru 20w-50), and the different temps that they were used at, represents a far greater difference then the 5w-20 represents when compared to 10w30. If it was a simple matter of viscosity I would reason that one would encounter either increasing or decreasing PSID upon start up depending on what weight you were using ..and that it would increase or decrease more the further you went in either direction. This, IIRC, hasn't happened in any other case unless the pump relief is open. So I would have normally expected anything BUT a 10 PSID upon startup with 5w-20. Lower pressures across the board would have been accepted as normal.
Since it returns to the normal 4 PSID very quickly, we may be able to throw out the engine presenting that much less of a restriction in comparison to the filter at startup. This should not change if this is so. This may lead us to look at the filter as the cause, but I can't figure out what it is.
For all I know it's a property of the oil.
Gary, maybe the 5w-20 is not creating enough pressure to open the pump bypass (or open it a lot), therefor all the oil is going through the filter and creating a higher initial psid. Perhaps with the heavier oils, the pressure was high enough to open the pump bypass by not enough to relieve all the differential pressure in the filter, which therefor showed a lower psid initially (because the extra pressure was bled off in the form of oil to the pan).
I second drew's explanation.
Gary,
Can you post the startup pressures for the various oils in one post. I can't find all the data for the three oils you have used.
Gary,
Can you post the startup pressures for the various oils in one post. I can't find all the data for the three oils you have used.
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My log is with the van in Lock Haven. It will return on the 14th.
The only time the pump has been in relief is with 15w40 and 20w-50. In the case of the 15w40 ..the pump side pressure went to 82 psi (the limit) and the engine side stopped its upramp at 70. As you accellerated they met in the middle more weighted toward 80 psi.
In the case of the 20w-50, the viscosity was so high that the 3/8" lines became part of the equation. I'm uncertain of the actual number off hand ..but I never reached 82 PSI at the pump side, IIRC. I believe that PSID started out at maybe 10-12 ..and then both advanced toward 80 psi ..but never reached it.
No oil has been in pump relief for very long at all. It's all very dynamic and the transitions are very rapid. Now admittedly this wasn't conducted in sub-freezing weather but I did see one overnight parking that had a low of 32°F. Since that was the low, it's not like a full 8-12 hours @ 32F.
There is the possibility that the pump relief is not a perfect seal (although about 8k ago I had 10w(20) LL in there and saw no such activity ..but then again my guages were under the hood during that time). That would explain the "resistance to motion" type event that I'm seeing. It would also show up more with a thinner oil below the pressure relief limit.
The only time the pump has been in relief is with 15w40 and 20w-50. In the case of the 15w40 ..the pump side pressure went to 82 psi (the limit) and the engine side stopped its upramp at 70. As you accellerated they met in the middle more weighted toward 80 psi.
In the case of the 20w-50, the viscosity was so high that the 3/8" lines became part of the equation. I'm uncertain of the actual number off hand ..but I never reached 82 PSI at the pump side, IIRC. I believe that PSID started out at maybe 10-12 ..and then both advanced toward 80 psi ..but never reached it.
No oil has been in pump relief for very long at all. It's all very dynamic and the transitions are very rapid. Now admittedly this wasn't conducted in sub-freezing weather but I did see one overnight parking that had a low of 32°F. Since that was the low, it's not like a full 8-12 hours @ 32F.
There is the possibility that the pump relief is not a perfect seal (although about 8k ago I had 10w(20) LL in there and saw no such activity ..but then again my guages were under the hood during that time). That would explain the "resistance to motion" type event that I'm seeing. It would also show up more with a thinner oil below the pressure relief limit.
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