Recent Topics
Aegis 20/50 Classic.
by Silk
21 minutes 54 seconds ago
Tire Gauge Reviews
by joel96
Today at 01:21 AM
Recommended ATF change for "Sealed 4 Life" tranny
by Stewie
Today at 01:08 AM
PL14670 ~10,000 mi
by MinamiKotaro
Today at 12:10 AM
Perplexing math
by mjoekingz28
Yesterday at 09:54 PM
1998 Expedition 5.4L Spark Plug Torque Setting
by lvt
Yesterday at 08:52 PM
Long vs short oil filter
by yankees1
Yesterday at 08:51 PM
Trash Pump Question
by Michael_P
Yesterday at 08:23 PM
Bosch Plug
by DarthDuty
Yesterday at 08:14 PM
Mix Oil Brands for Oil Change?
by BHopkins
Yesterday at 07:29 PM
Pepboys oil?
by 4Scott4
Yesterday at 07:25 PM
oil for my jeeps ax-5
by hansj3
Yesterday at 07:24 PM
Newest Members
ScienceGuy, DAD105, Matsbugs, ReverendC, bandk
53414 Registered Users
Who's Online
36 registered (Bookmaker, car51, Char Baby, Boomer, bourne, 8 invisible), 582 Guests and 189 Spiders online.
Key: Admin, Global Mod, Mod
Forum Stats
53414 Members
66 Forums
229072 Topics
3661517 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 Offline


Registered: 03/31/12
Posts: 324
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 Offline


Registered: 01/10/08
Posts: 4923
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: 12612
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 Offline


Registered: 03/31/12
Posts: 324
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 Offline


Registered: 01/10/08
Posts: 4923
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: 8377
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: 641
Loc: Florida
My silverado has 40psi at idle (700rpm) and about 50 in the morning at idle. With 5w30
_________________________
2003 Suburban PYB
2001 Suburban PYB
- - - - - - - - -- - - - - - - -- - - - - - -- - -
I like oil too much & ALWAYS PYB

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


Registered: 09/10/05
Posts: 3854
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: 3332
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