Will syntectic lower oil pressure compared to dino

[jaytone]

I need to get my oil pressure down. I was running Rotella 15w40 and then switched to Valvoline VR1 straight 30. The straight 30 did lower it some, but would like to lower it more.
My engine builder said do not use 10/30 as it is to light but straight 30 is fine
Question is, would the oil pressure using synthectic oil 30 weight be lower than regulary conventional oil that was also 30 weight.
FYI, its a big block chevy engine.

 

[Steve S]

why would you need to get your oil pressure down? 15w40 is an excellent oil for big blocks.

 

[OVERKILL]

Do you have a high pressure oil pump?

Oil pressure is a function of pump output and bearing clearances, and how is 10w30 too "light" ?

How much pressure is too much in this case?

 

[jaytone]

When it reaches operating temperature the psi is at 42 idling (1000 rpms) and psi is 68 at crusing (2800 rpms)using the Valvoline VR1 straight 30. (Was at 50 idle and 80 cruising with the Rotella 15w40) Cold idle is much higher until it reachs 180 degrees operating temp.
The pump is a new Moroso High Volume but standard pressure.

Are the numbers above anything to worry about ?

WOuld the pressure be lower using synthectic 30 compared to 30 conventional?

 

[OVERKILL]

No, that's nothing to worry about. My old 302 has 38psi at 850RPM and the blow-off for the pump happens at 65psi, which it hits quite readily when flogged. This is a stock 1987 bottom-end with the stock pump running Mobil 1 5w30 or Mobil 1 10w30 synthetic.

I thought you were going to say it's making like 120psi at idle or something

And I doubt there would be any measurable pressure difference between a conventional and a synthetic.

 

[Gary Allan]

Quote:
WOuld the pressure be lower using synthectic 30 compared to 30 conventional?


Not much. If they're both 10.5CST @ 100C (or there abouts) ..they'll both be 10.5CST @ 100C.

......

Now below that oil temp they'll spread out ..and continue to diverge the cooler they are.

 

[Doug Hillary]

Hi,
jaytone - Typically you can expect a lower hot OP with a synthetic lubricant over a similar viscosity mineral lubricant

This is primarily due to the better and more linear flow characteristics of most synthetic lubricants

At higher revs the OP should be very similar

 

[Lazy JW]

This engine is just BEGGING for a 5w30 synthetic oil. Give it what it wants and it will reward you greatly.
Joe

 

[jaytone]

Thanks to everyone for you help, most appreciated