Recent Topics
3rd time's the charm (Cruze water pump)?
by sciphi
11/28/14 12:58 PM
Netgear Nighthawk ac1900 router <90$ walmart YMMV
by Rand
11/28/14 12:33 PM
Barn car tires worth saving?
by subaru1991
11/28/14 12:32 PM
Dexos 1 Question
by Sierra048
11/28/14 12:08 PM
Black friday computer kit for me Deals
by oilboy123
11/28/14 11:46 AM
What fluid for my Acura TL 6MT SH-awd
by PeterGreen
11/28/14 11:08 AM
Purolator PSL24651, 6000 miles, Ram 4.7, M1 0w20
by 440Magnum
11/28/14 10:40 AM
E10 in 2013 Honda Accord sport
by Mark72
11/28/14 10:17 AM
A question: 2 cycle oil and octane level
by Mephy
11/28/14 10:13 AM
Is the G-Oil hype over with
by MalfunctionProne
11/28/14 09:59 AM
Additives settle out?
by 4wheeldog
11/28/14 09:56 AM
I gambled and lost
by Bottom_Feeder
11/28/14 09:49 AM
Newest Members
GON, Jo5eph, Kernel, EdBurns, wolf9832
52014 Registered Users
Who's Online
73 registered (Anthony, 94astro, 3800Series, 2010_FX4, 87sammy, 11 invisible), 1699 Guests and 164 Spiders online.
Key: Admin, Global Mod, Mod
Forum Stats
52014 Members
66 Forums
222716 Topics
3525829 Posts

Max Online: 2862 @ 07/07/14 03:10 PM
Donate to BITOG
Topic Options
#3346414 - 04/18/14 10:51 AM Typical oil pressures in an engine?
HKPolice Online   content


Registered: 03/31/12
Posts: 207
Loc: Toronto, Canada
Seems like most filter bypass springs open up at around 12-18psi but when I google typical oil pressures, people are posting figures WAY above that. Apparently it's normal to idle around 10psi and for every 1000rpm it goes up another 10psi?

Wouldn't the filter be in bypass mode most of the time? I was under the assumption that filters don't bypass except for when the oil is really cold & thick and when near redline.

Top
#3346416 - 04/18/14 10:55 AM Re: Typical oil pressures in an engine? [Re: HKPolice]
bepperb Online   confused


Registered: 01/10/08
Posts: 4824
Loc: Milwaukee, WI
The filters open when there is a difference between the input and output sides. It doesn't matter what the total pressure is, only the difference.

So if an engine was driving down the highway with 50psi going into the filter and 48psi coming out and the bypass was 10psi it wouldn't be close to opening.
_________________________
2004 Highlander 2.4
2011 Toyota Sienna 3.5
Recently Gone:
2006 Accord 2.4l K24A8
1993 Kawi EX 500

Top
#3346420 - 04/18/14 10:59 AM Re: Typical oil pressures in an engine? [Re: HKPolice]
dparm Offline


Registered: 04/19/10
Posts: 12570
Loc: Chicago, IL
10psi per 1000rpm is a ballpark, yes.
_________________________
2011.5 BMW M3 saloon ZCP
der stärkste buchstabe der welt
Castrol Edge Professional TWS 10w60 + Mahle OX 254D3

Top
#3346427 - 04/18/14 11:03 AM Re: Typical oil pressures in an engine? [Re: bepperb]
HKPolice Online   content


Registered: 03/31/12
Posts: 207
Loc: Toronto, Canada
Originally Posted By: bepperb
The filters open when there is a difference between the input and output sides. It doesn't matter what the total pressure is, only the difference.

So if an engine was driving down the highway with 50psi going into the filter and 48psi coming out and the bypass was 10psi it wouldn't be close to opening.


Oh ok I get it now. Are there any figures for typical pressure drops for oil filters? Any tests to see the amount of trapped contaminates needed to cause pressure drop?

Top
#3346466 - 04/18/14 11:33 AM Re: Typical oil pressures in an engine? [Re: HKPolice]
bepperb Online   confused


Registered: 01/10/08
Posts: 4824
Loc: Milwaukee, WI
You've come to the right place. This is old but a good place to start:

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=314996

At one point someone had a similar setup in their car but I cant' find a link (I didn't look hard).
_________________________
2004 Highlander 2.4
2011 Toyota Sienna 3.5
Recently Gone:
2006 Accord 2.4l K24A8
1993 Kawi EX 500

Top
#3346558 - 04/18/14 01:31 PM Re: Typical oil pressures in an engine? [Re: HKPolice]
ZeeOSix Offline


Registered: 07/22/10
Posts: 7596
Loc: PNW
Originally Posted By: HKPolice
Originally Posted By: bepperb
The filters open when there is a difference between the input and output sides. It doesn't matter what the total pressure is, only the difference.

So if an engine was driving down the highway with 50psi going into the filter and 48psi coming out and the bypass was 10psi it wouldn't be close to opening.


Oh ok I get it now. Are there any figures for typical pressure drops for oil filters? Any tests to see the amount of trapped contaminates needed to cause pressure drop?


Enjoy ... real test data from Purolator on a PureOne filter of average size (used on a 405 HP V8). As you can see, with hot oil a filter will flow lots of oil with not much pressure drop across the filter.

http://www.bobistheoilguy.com/forums/ubb...451#Post1619451

Top
#3346563 - 04/18/14 01:32 PM Re: Typical oil pressures in an engine? [Re: HKPolice]
Realtech214 Offline


Registered: 02/01/13
Posts: 632
Loc: Florida
My silverado has 40psi at idle (700rpm) and about 50 in the morning at idle. With 5w30
_________________________
2003 Silverado "Old PU" 5w30
2001 Suburban 15w40 Plus50II
- - - - - - - - -- - - - - - - -- - - - - - -- - -
I like oil too much

Top
#3346573 - 04/18/14 01:45 PM Re: Typical oil pressures in an engine? [Re: HKPolice]
Zaedock Offline


Registered: 09/10/05
Posts: 3843
Loc: Massachusetts
As mentioned, oil filters bypass with differential pressure.

This can occur when the engine is cold and the oil is viscous and it can also occur for a moment at operating temp when you go wide open throttle.
_________________________
2012 F150 Ex-cab 5.0L/2004 Malibu Maxx LT
1992 YJ "The Heep"/1994 Olds Cutlass Ciera 3.1/auto
1975 Ford Bronco/1959 Willys CJ5/20XX Custom rock crawler

Top
#3346764 - 04/18/14 05:47 PM Re: Typical oil pressures in an engine? [Re: HKPolice]
RF Overlord Offline


Registered: 11/08/03
Posts: 3184
Loc: Cape Cod, MA
Ford modular (4.6L etc) can have 100 lbs pressure at cold startup, but settle down to 25 at hot idle. I believe this is one of the reasons Ford insisted on putting fake gauge in their cars.
_________________________
Supercharged '03 Mercury Marauder - Trilogy Motorsports #61
PP 5W-30 / MC FL820S

Y2K Grand Marquis GS - daily driver
MC 5W-20 / MC FL820S

Top