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Discussion Starter · #1 ·
I am looking at doing a oil bypass filter on my 08 and after looking I can find lots of single and dual filter heads that people are calling bypass but when I asked one seller says it's a Full flow.
I guess my question is is it the adapter that you screw too the oil filter position on the engine be it either a relocation adapter or sandwich adapter that makes it full full flow VS. bypass or is it a filter head design or is it just the filter that limits the flow.
 

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there are full flow filters, and then there are bypass filters, sometimes it also depends on how they are plumbed in, I would go with the AMSOIL kit if i were going to do one
 

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Discussion Starter · #3 ·
So you're saying the only difference is the filter not any of the hardware.
 

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Im pretty sure i have seen some bypass 'heads'

but yes, filters are made to flow differently
 

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Discussion Starter · #5 ·
I know some filters have a bypass feature that allows the oil too flow even at cold temperatures or if the filter is pluged what that does is it bypasses the filter media and just recirculates which is not the same thingThat's a whole different thing. And I know that high Efficiency filters that work in the 2 to 3 micron range are not made for full flow and pressure. Even if I go with a Amsoil set up I would still like to know how it works.
 

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The amsoil bmk27 has 2 filters on it. It comes with a full flow and a bypass. The Full flow is basically your regular oil filter. The bypass filter is the one that filters out the smallest particles. But only does a small amount of oil at a time due to it being more restrictive.
 

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So whichever setup you choose you still need a higher flow or full flow filter. The bypass just filters down to a smaller micron. The bypass kit just puts them both on one filter head as where the remote or single bypass utilizes your factory filter as the full flow and adds the bypass filter via a sandwich adapter.

Hope this helps!
 

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Let me help a little. To answer your question is is the bypass filter head that is what does the work so to speak.

Here is the way it works on the dual bypass system. The system uses an adapter that replaces your regular (full flow) oil filter. That filter if its an ACD Delco filter is a 40 micron (mic) filter. 40 mic is about the width a human hair. The oil runs through the adapter to the bypass head where there is inlet and outlet channels that the oil runs through from the engine and through the filters and back to the engine. The bypass head internally has what is like a jet in a carb that restricts the oil flow through the bypass filter (larger of the two) which is a 2 mic filter. That makes it so approx 10-14% of the oil that passes into the filter head runs through the 2 mic bypass filter the rest runs through the full flow filter which is a 20 micron filter. The reason for this is a 2 mic filter is so restrictive that you wouldn't get the flow (psi) and volume needed for protection if you ran it all through there.

The calculations are that when running down the hwy at speed the entire sump will be seen by the bypass filter every 20-25 minutes at 2 mic. The dual bypass unit also increases the sump capacity by 2-3 qts depending on your system. Mine takes 2.5 more qts to get topped off. If you put a single bypass on the same thing applies. The single bypass uses a sandwich adapter that retains the factory full flow filter. The oil flows through the sandwich adapter to the bypass head using a restricted opening going to the 2 mic bypass filter and takes only a portion of what passes through the system to the filter head and the 2 mic bypass filter.

Hope that helps clear it up a little on how they work. They are awesome systems and if anybody is interested in one contact me and I can show you how to save some money on it as well as show you the bracket I have fabricated to mount the duel bypass to a Duramax frame saving 1-2 hrs in fabrication and drilling holes to mount it in the frame or elsewhere. :thumb
 

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What is the advantage of running the dual bypass vs the single bypass?

With the single bypass, you could utilize either the M-303 or the Ams filter (@ 18µm & 15µm respectively) in the OEM position, followed up by the 2µm bypass filter.

Or is that 20µm spec on the full flow incorrect?
 

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What is the advantage of running the dual bypass vs the single bypass?

With the single bypass, you could utilize either the M-303 or the Ams filter (@ 18µm & 15µm respectively) in the OEM position, followed up by the 2µm bypass filter.

Or is that 20µm spec on the full flow incorrect?
When the whole test specification change came about recently the 15um went to a 20um. That is the same thing that took the 2um cat fuel filter to a 4um.

The only draw back to a single bypass unit is there is usually more hose used meaning longer runs which equates to possible volume and pressure loss. Also one more joint to leak from the sandwich adapter/oem filter. Many times the return line ends up in the fill hole cap on the valve cover or on the fill tube on our dmax's which can be a hassle sometimes.
The dual bypass eliminates the sandwich adapter by eliminating the oem oil filter and simply uses an adapter that replaces the oil filter rather than an adapter and a filter on top of the adapter. In our applications where our mounting bracket is used with a dual bypass the hoses are 11 1/2" long because we designed our bracket to mount as close to the oil filter location as possible.
Splitting hairs here but when using a dual bypass both filters are in the same location meaning put your catch pan down once and work right there where on a single the two filters (oem & bypass) are in different locations so you have to move around to remove both filters. Lastly the Amsoil Dual bypass adds more oil to the sump than a single bypass does which I also like having more oil.

Again some of my points are splitting hairs in a respect but I have been working on cars all my life and as I have gotten older, fatter and less nimble climbing under cars my goal is to make my maintenance program and clean up from maint. as easy as possible, not harder and or more time consuming. That is why I use a fuel filter access door for the fuel filter and an oil drain valve on my oil pan its so much cleaner and easier. That is why I prefer a dual bypass to a single because both filters are right there and straight up and down rather than on a 45 degree angle (oem) and dripping on stuff when the flow gets to almost nothing. As far as filtering they both do about the same job if we are talking Amsoil brand units. because we know that the full flow Amsoil filters are 20um and the bypass filters are 2um. The variable is when other brand bypasses are used, the filters usually are not as efficient as the Amsoil filters or people try to be penny wise and dollar foolish and buy cheaper filters not paying attention to the um rating or looking at the nominal um rating not the absolute. Then they defeat the purpose by using filters that are 25, 30 40um sometimes without knowing.
 

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Ah, okay...15-20, that's what thru me, I had thought they were the same filter element used.

Also, now I remember, the other is under the hood.
I had envisioned both down on the frame rail and couldn't see the logic.

I wonder, why not alter the single sandwich to a closer frame rail mount and shorten the hose lengths?
 

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Ah, okay...15-20, that's what thru me, I had thought they were the same filter element used.

Also, now I remember, the other is under the hood.
I had envisioned both down on the frame rail and couldn't see the logic.

I wonder, why not alter the single sandwich to a closer frame rail mount and shorten the hose lengths?
Yeah I still consider the Amsoil filters 15um but they are advertised as 20um absolute now so gotta go with that. It can be done but would take a fair amount of fabrication on the customers part. Which is why I like our bracket and the Dual bypass because all the guess work and fabrication has been taken out of it just bolt everything on in an hour and away you go.
 

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I have the a amsoil setup. Interesting as to how it works thanks for explaining. I typically get around 18,000 miles per oil change. I do submit samples to blackstone labs during that run. I have the mount/bracket you speak of. Well worth the cost and makes the install really nice. Had the setup for a year or so hopefully it is worth the investment.
 

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Hopefully you are doing the TBN test when submitting to Blackstone.
 
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