I recently changed my oil and put in 5qts of mobil one 5w 30.

I noticed that under full throttle in the high rpms, my oil preasure guage reads full preasure at 120.

anyone else experence this???

 

I never looked before I switched, nor have I looked now. I'm gonna check today after work and see where it goes under WOT.

 

yep, I certainly do. I switched to 5W-30 Mobil 1 and switched to a larger NAPA oil filter, 1356. I did notice an increase in my oil pressure. In case you are wondering, this is not a bad thing.

 

I know its not a bad thing, I just found it a little odd that it would jump that much. Those nissan filters are rediculously small.

 

yep same on my car. did the same on the eclipse i had when i switched to synthetic. it didn't read "max" pressure on the guage in the mitsu, but it read higher than the regular oil that i was using before the switch.

jon

 

Same here. I was a little worried at first. I'm glad to see others are seeing the same thing

 

I am getting the high pressures too. I went to the Mobil 1 5W-30 and a Bosch oil filter. At first I thought it was the filter causing the problem. But after seeing this thread it must be the oil.

Now the other question is this: the oil pressure is measured before the oil filter and there is a relationship between pressure and flow volume.

So is more pressure an indication of more or less oil flow?

 

More pressure (if due to the oil filter) would equate to less flow/more restriction.

My thought on the increased pressure is: Perhaps the pump is more efficient with the smaller molecules of synthetic oil? Did anyone keep the stock filter when switching to synthetic to see if it was the oil, or the filter? Or, is anyone running one of these filters with non-synthetic?

 

I will be switching to sythetic this weekend and was told the stock oil filter will be fine. So I will let you guys now how it comes out. It should most likely come out the same I think

 

With the stock filter, synthetic will always make the pressure a little higher.......I've found that whenever I've put Mobile 1 synthetic in my other sports cars, I've always kept the stock filter, but the pressure has always gone up a bit. Nothing to worry about.

 

I am running the stock filter. It must be the oil.

 

ponykiller, it is much more complicated than that. Alot depends on the filter, oil, and such. An increase in pressure could be attributed to a number of things, not just a restriction. The Nissan filters are not very well constructed, and a filter with more filtering ability like the PureOne could cause an increase in pressure just cause it is filtering out more contaminants.

There are also other variables that I won't go into, but the point is, it is much more complicated than that.

 

I am running Mobil Syn 5w30 with a stock filter and took notice of the same 120psi pressure reported here.

I don't think I ever noticed the pressure before when running dino b/c the needle didn't fluctuate as much.

The factory service manual states a pressure of 57psi at 6000rpms is "normal."

Can anyone shed some light on this phenomenon?

 

I know this is an old post, but I will be switching to synthetic soon and wanted to know if anyone figured anything out?

 

I switched to mobil 1 syn and my oil pressure went to 120psi which isnt really good. All that means is that the oil is moving so fast that it actually blows by the oil filter thus not properly filtering out the oil.

My last oil change I went to the stock recommended weight in Royal Purple and immediately the PSI went to normal. At full throttle it goes to 90psi.

I bought the oil at a local auto parts store, and it was less than a dollar more a quart of mobil 1. And yes the oil is purple.

 

Would using a Mobil 1 filter make a difference? I'm guessing that that filter is designed for the unique properties of synthetic oil. Yes/No?

 

Ummmmm, back to physics class. Generally, the greater the velocity of a fluid, the lower the pressure. Carburetors functioned on this principle; the pressure drop from the increased speed of the air passing through the venturi was how the fuel was drawn into the intake air stream. EDIT FOR CLARIFICATION: The pressure increase you typically see with increased rpm is NOT from the oil flowing "faster," it's from the pump introducing a greater volume of oil into the lube system in a given time (although a few other factors are at work too, such as viscosity at the moment, etc.)

The absolute psi on your oil system will have no bearing on whether the oil goes through the full-flow filter element or not. It's only when the difference in pressure between the intake side and the output side of the filter exceeds the threshold of the bypass valve, that oil will be allowed to get around the filter element.

More is not necessarily better with oil pressure. Within the designed range of pressure, that's probably true, but above the design maximum, you risk pressure tearing through the seals designed to keep the oil where its supposed to flow. As an example, in the jet I used to fly in the Marines, the engines were limited to 50 psi max oil pressure (35-50 being normal). If it ran above 50, and you couldn't control it with the throttle, in-flight shut down was mandatory (unless, of course, you'd already shut the other one down...). VQs and J-52s are very different devices, but the principle is the same: stay within proper pressure range with the correct oil type and weight, and you should be fine.

 

You would think so but I am not sure? I guess you could try it and see what happens. Would be really easy to do on your next oil change.

I actually buy my filter at walmart and have them do it. They have been doing it from day one.

I am coming from the LS1 guys and they cared a lot about oil and someone actually did tests on all different kinds of filters. Awesome experiment! One of the lowest filter ratings was Fram, the highest was I believe K&N and right there was wally worlds brand supertech. So when I tell them to use supertech oil filter they think I am crazy.

I used supertech on my heads/cam WS6 and now I use it on my 350Z. Stock recommended filter (supertech) and oil (royal purple).

 

yeah I said the same thing but they easy way. I havent took college physics yet, but took it in highschool. I remeber seeing a model of air pressure and it deffinately showed at a high level (the maximum) the air would go right past any "holes". The concept of the path of least resistance (thats how I remember it, not really the "title"). So in theory its not going to "stop off" at the filter.

 

Hope I didn't sound heavy-handed there. . . I guess part of my point is that in a closed, full-flow filter system (i.e. pretty much every automotive gasoline engine built since the mid-1960s), there's no place for the oil to go, except through the filter element, UNLESS, the filter bypass opens. This will not happen as a result of high oil flow velocity, but rather, when the pressure drop across the element exceeds the opening pressure of the bypass valve. The pressure drop can result from a clogged/over-restrictive filter element, overly viscous oil, or a combo of both. As I recall, the stock filter bypass pressure differential is 14 psi (someone correct me if I got that one wrong...).