Recent Topics
Like pasta with your pesto?
by JHZR2
03/28/15 07:32 PM
2000 Impala LS ignition switch replacement
by Tzu
03/28/15 07:20 PM
Recommended oil weight for high mileage vehicle?
by Nicholi2789
03/28/15 06:53 PM
Chase Elliot...
by mattwithcats
03/28/15 06:17 PM
Accidentally mixed grease. How much time do I have
by Bigsyke
03/28/15 06:14 PM
Which Mobil 1 in a Ford V-10
by loneryder
03/28/15 05:53 PM
P300 and P1174 codes on 2007 Pontiac G6 with 2.4L
by wtd
03/28/15 05:41 PM
Rotella T5 discontinued and clearanced at Menards
by Scott_mi
03/28/15 05:40 PM
Return used oil to Walmart for a refund?
by Merkava_4
03/28/15 05:35 PM
w126 300sel- Torque Converter Drain
by Gito
03/28/15 04:53 PM
Question about Rislone.
by Cristobal
03/28/15 04:27 PM
Exploding targets!
by OVERKILL
03/28/15 04:24 PM
Newest Members
Nicholi2789, cycleguy55, Dolph, s1xstr1ng, grover12
53350 Registered Users
Who's Online
109 registered (AandPDan, -SyN-, 901Memphis, 2010_FX4, Al, aquariuscsm, 11 invisible), 1732 Guests and 182 Spiders online.
Key: Admin, Global Mod, Mod
Forum Stats
53350 Members
66 Forums
228815 Topics
3656549 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: 8369
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: 3327
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