30psi Bypass?!?!

[Tyrolkid]

After help from Patman and others on this forum, I picked up an oversize NAPA Gold 1333 for both my Mustang 5.0 and VW 1.8T. Before installing it, I cross-referenced this PN on the wix website. The wix equivalent is used on a lot of diesel engines, and has a 30psi bypass.

I then cross-referenced the externally identical Napa Gold 1773, and it has a more reasonable 8-11psi bypass. The factory spec filter from wix for the VW 1.8T(Gas) has a 33psi bypass. Two questions:

1) Why such a high bypass level?

2) Would using an 8-11 bypass filter hurt?

-Mike P

[ February 17, 2003, 04:11 PM: Message edited by: Tyrolkid ]

 

[Al]

Well 30psi sounds pretty high. However I would be reluctant to drop much lower than that value. Bypass means thatdirt is washed off of the outside of the filter. Thats just my opinion. Hopefully someone will be able to provide a more technecially correct answer based on your particular vehicles.

 

[Tyrolkid]

With a factory spec 33psi bypass, it would seem that VW wants oil to flow through the filter media at all costs. I did some more searching on the WIX site, and almost all of the VW/Audi applications have 30-33psi bypass settings, ditto Mercedes and BMW....

[ February 17, 2003, 04:32 PM: Message edited by: Tyrolkid ]

 

[ShootingStar]

quote:

---

Originally posted by Al:
Well 30psi sounds pretty high. However I would be reluctant to drop much lower than that value. Bypass means thatdirt is washed off of the outside of the filter. Thats just my opinion. Hopefully someone will be able to provide a more technecially correct answer based on your particular vehicles.

---

I agree, 30+ psi sounds very high. Your statement that "Bypass means that dirt is washed off of the outside of the filter" may or may not be true. Some filters have the bypass on the thread/gasket end of the can, thereby redirecting the bypassing oil back to the outlet WITHOUT flowing over the media. Some have the bypass in the top of the can, and this COULD flush the junk suspended on the surface of the media back into the motor.

 

[jsharp]

quote:

---

Originally posted by Tyrolkid:
After help from Patman and others on this forum, I picked up an oversize NAPA Gold 1333 for both my Mustang 5.0 and VW 1.8T. Before installing it, I cross-referenced this PN on the wix website. The wix equivalent is used on a lot of diesel engines, and has a 30psi bypass.

I then cross-referenced the externally identical Napa Gold 1773, and it has a more reasonable 8-11psi bypass. The factory spec filter from wix for the VW 1.8T(Gas) has a 33psi bypass. Two questions:

1) Why such a high bypass level?

2) Would using an 8-11 bypass filter hurt?

-Mike P

---

You might consider just using the Motorcraft FL1A on your 5.0L. They have the top bypass specified by Ford and other than the thin case appear to me to be pretty good quality. I'm considering using those on all my vehicles like I used to and forgetting all this "filter mania" we've got going here.

Also, the FL1A is $2.77 at WalMart...

[ February 18, 2003, 09:00 AM: Message edited by: jsharp ]

 

[Mike_dup1]

Diesel engines can generate more oil pressure the most gas engines.

Here is a GM TSB for reference, I highlited in the bold the revelent info on this.

quote:

---

Bulletin No.: 00-06-01-025A
Date: September, 2001
INFORMATION
Subject:
Correct Oil Viscosity and Oil Filter Usage for the Duramax 6600 Diesel Engine (RPO LB7)
Models:
2001-2002 Chevrolet Silverado and GMC Sierra 2500 HD and 3500 Models with 6.6L Engine (VIN 1 - RPO LB7)
This bulletin is being revised to add the AC Delco oil filter part number and add the 2002 Model Year. Please discard Corporate Bulletin Number 00-06-01-025 (Section 06 - Engine/Propulsion System).
Important :The Duramax 6600 diesel engine can produce oil pressures over 690 kPa (100 psi) during a cold start condition and the oil pressure gauge may remain near 552 kPa (80 psi) while driving. Because of these oil pressures, it is important that the correct oil filter is used and torqued properly and the proper oil viscosity is used for the ambient temperatures.
Oil Filter
The correct oil filter for use on the Duramax 6600 engine is the AC PF2232 or the production oil filter, GM P/N 97214983. This filter was designed specifically for use on the Duramax 6600 engine and incorporates improved filtering capabilities as well as an integral oil pressure relief valve. The oil filter should be torqued to 24 N.m (18 lb ft) to prevent leaks under high pressure conditions.
Oil Viscosity for Cold Weather Operation
SAE 5W-40 viscosity oil designated as API CH-4 or CG-4 should be used if the ambient temperature falls below -18°C (0°F) to prevent excessive oil pressure on a cold start. Refer to the Owner's Manual diesel supplement for additional information on proper oil usage for other operating conditions.

---

 

[TooSlick]

Mike P,

VW/Audi engines run very high oil pressure and in addition they have traditionally recommended heavy, 15w40/15w-50/20w-50 oils for hot weather use. I believe these are the two main reasons why they all have a high PSID rating for the by-pass valve. I have been running the Amsoil SDF oil filters in these engines - which have an 8-10 psid by-pass valve - for over twenty years will no ill effects. My oil analysis results are excellent, so I'm not sure how much of a factor this is, provided you use a high flow, synthetic media filter. I should add that I have also been primarily running the Amsoil 10w30 and 0w30 synthetics in these engines, so the oil flow much better during the warmup period than if I were running a 20w-50 grade.

TooSlick

 

[Tyrolkid]

quote:

---

Originally posted by TooSlick:
Mike P,

VW/Audi engines run very high oil pressure and in addition they have traditionally recommended heavy, 15w40/15w-50/20w-50 oils for hot weather use. I believe these are the two main reasons why they all have a high PSID rating for the by-pass valve. I have been running the Amsoil SDF oil filters in these engines - which have an 8-10 psid by-pass valve - for over twenty years will no ill effects. My oil analysis results are excellent, so I'm not sure how much of a factor this is, provided you use a high flow, synthetic media filter. I should add that I have also been primarily running the Amsoil 10w30 and 0w30 synthetics in these engines, so the oil flow much better during the warmup period than if I were running a 20w-50 grade.

TooSlick

---

TooSlick-

The new VW/Audi oil recommendations for the 1.8T are 5w30,5w-40, yet they still retain the high bypass levels. Weird. I have been inadvertently running Mobil1-301 filters with an 8-11 bypass for the last two changes on Redline 5w-40. Analysis results have been excellent as well. Another nail in the bypass valve coffin?

Next change, I will return to using the 30psi rated bypass filter, so that more oil flows through the media......I'm beginning to think it doesn't make sh!t of a difference....

-Mike P

 

[dbrowne1]

This filter has another advantage too, one that I think is more important than the thermal one found in having higher oil capacity.
The modified K03/K04 turbos that fail may very well be doing so due to momentary drops in oil pressure at the bearing leading to contact between the shaft and bearing, then eventually between the turbine/compressor and respective housings. This is similar to the concern about using 30 weight oils in modified cars. To the extent that this filter keeps pressure at the bearing more consistent, it will help prevent this.
Audi now uses 0w30 and calls for that weight, but only because they know that the turbos will tolerate the factory oil/filter system if they're not making higher boost than what is set at the factory. So they can use this weight to improve CAFE numbers. Start spinning it harder and putting on aftermarket intakes and exhaust downpipes and things change.

 

[Patman]

quote:

---

Originally posted by jsharp:
You might consider just using the Motorcraft FL1A on your 5.0L. They have the top bypass specified by Ford and other than the thin case appear to me to be pretty good quality. I'm considering using those on all my vehicles like I used to and forgetting all this "filter mania" we've got going here.

Also, the FL1A is $2.77 at WalMart...

---

The Wix filters (both the NAPA Gold and the Carquest premium) I bought for my mom's Probe GT have the bypass in the top also.

 

[jsharp]

quote:

---

Originally posted by Patman:
The Wix filters (both the NAPA Gold and the Carquest premium) I bought for my mom's Probe GT have the bypass in the top also.

---

My favorite local autoparts store sells Wix. It's one of those old time/small town stores with attractive women behind the counter. I'll stop there and look at one. The Wix filters I mean.

 

[vw_kayaker]

I just posted the same question. Guess I should have read a lttle farther down first. I guess if the oil analysis reports come back looking good for me I'll stick with it ( the M1 301).

 

[cryptokid]

my pops diesel hit 1650psi oil pressure one morning. bust that oil filter wide open.

 

[vvk]

Subaru bypass valves are 23 psi. I wonder what Honda's are... People often seem to substitute a bigger Honda CRX filter on their Subarus...

Interestingly, WIX lists only 8-11 psi for their Subaru applications... Weird

 

[Ken2]

Mike,

We don't know for sure why an engine maker specifies the filter that he does. He has the whole universe of filters available, and invents a filter if there isn't one off-the-shelf that he likes. Aftermarket filter companies reverse engineer the OEM filter to develop their line of filters.

So...I'm not comfortable second guessing the engine maker's filter choice. If an 8 psid bypass filter worked better, wouldn't the engine maker spec it...it doesn't cost any more? Or does he know more about his engine than all of us here put together? I understand, there's always pressure to cut every corner and save every penny in engine design and production, and that also includes efforts to minimize warranty claim costs.


Ken

 

[Cressida]

I too have been puzzeled by the wide range of bypass pressures on the filters that can be used on my engine (Toyota 5mge). I normally use a large FL1A or PH8A type of filter that has the bypass rated at ~8 psi. The Toyota originally was recommended at 16-20 psi and some cross references are to a Fram PH2870A (also common to VW's) which is listed at 30 psi. Seems like a wide range of bypass pressures.

After thinking on it, I've concluded that I always prefer a good flow of oil to the engine so I'm comfortable with the lower by pass ratings. Perhaps at 30 psi I'd still have plenty of oil going to the engine but I have no way of knowing. So what if my 8 psi filter goes in bypass more often ? From past oil analysis results that I've done and from the many that I've seen posted here, there are few that would lead me to be concerned that unfiltered oil is going to be harmful.

Also, I think it was Spectrum that has made the point that an oil filter may be like an appendix.

If I'm overlooking something somebody bring me back to reality

BTW, I found this link that has a good description and pictures of the parts on oil filters:

http://www.safari4x4.com.au/80scool/tech/oil_filter/filter.html

[ February 27, 2003, 09:44 PM: Message edited by: Cressida ]

 

[Ken2]

1) Those photos are of a very unusual filter. It appears to be one model of a filter used by Toyota, maybe made by Denso.

2) It's really splitting hairs when the author of that page says that the filter is not full-flow. All usual oil filters are called full-flow, and just about all bypass the oil when excessive differential pressure is reached (difference between the oil pressure entering the filter and the oil pressure leaving the filter), usually caused by thick, cold oil.

3) His concept of the whole media assembly moving down against the bottom spring and allowing bypass flow past the inlet/outlet seal in case of excessive differerntial pressure is interesting...I'll have to give that some thought.


Ken

 

[cryptokid]

i meant to say 165psi