Two bypass filters, low pressure variable oil pump, TDI EA 288 Audi A4 &A3

Joined
Apr 11, 2022
Messages
44
Hello, my name is Pedro and I am a big fan of bypass filters.
I had a Frantz filter fitted to each of my previous vehicles, before selling them I removed the bypass filters and saved them for my new cars.
I spent a lot of time investigating how to install it since from the beginning with the variable oil pump I had many doubts.

To do it right, buy a used filter body and cut it to study the oil flow, after the autopsy I saw that using one of the pressure sensors is not optimal since it is the flow already filtered, so the best way The way to get the flow out was by piercing the cap.
Very risky but using good materials it is possible, I will be aware of the market in case aluminum lids start to be manufactured.

I decided to use a 0.40 (1mm) flow restriction at the inlet of the first filter and the second mounted in series, this cost me a lot to decide to do but I had a clear objective which was to increase the oil capacity.

The vehicle is an Audi A4
2.0 TDI EA 288 euro 6, and has many problems with the dilution of oil by diesel

The driving profile is a very efficient style and average distances of 26 km there and 26 return, the oil temperature barely reaches 85° in winter and I suspect possible water condensation.

The return of the oil to the engine is at the oil drain plug, I was looking at the possibility of returning through the oil filler plug but this car has a valve cover with a PCV valve and there is a risk that the oil flow mixes with crankcase fumes

The driving profile is a very efficient style and average distances of 26 km there and 26 return, the oil temperature barely reaches 85° in winter and I suspect possible water condensation.

The return of the oil to the engine is at the oil drain plug, I was looking at the possibility of returning through the oil filler plug but this car has a valve cover with a PCV valve and there is a risk that the oil flow mixes with crankcase fumes

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Well I put some photos of the installation, I used new AN4 tubes, the toilet paper is from Costco that there are already stores in Spain, but in case there is any Spaniard who uses these Frantz filters, those from Mercadona are also good but they are slightly lower with 1cm .
As I have two Audis TDi in my wife's A3 I also put a double bypass filter, in this case the two filters are in the lower part of the engine, while in the A4 one is above and the other below, but in both they are installed from the same way.
Cheers
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What do you think of my double bypass filter configuration?

Tell you that this engine in Europe has 4.7l of oil capacity while in your country when it was sold it had 5.5l, the more oil capacity the fewer problems with dilution.
I have oil analysis reports and the A3 does 60km a day and at 5k it had 4% fuel, the A4 at 5k only 2% fuel.
Cheers
 
Does this installation have any impact on the design and function of the 2-stage electronically controlled oil pump? Just curious how you studied the flow rates at the differing stages of output and pressure regulation. You've tapped into the system downstream of the N428 control valve so I'm curious if the system compensates.

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Does this installation have any impact on the design and function of the 2-stage electronically controlled oil pump? Just curious how you studied the flow rates at the differing stages of output and pressure regulation. You've tapped into the system downstream of the N428 control valve so I'm curious if the system compensates.

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When I began to study the installation I saw the diagram that the second stage starts operating from 3000 revolutions, obviously I practice a very efficient condition and never exceed 2000 revolutions, I saw that the engine has variable intake and exhaust distribution and it seemed to me all very complex.
The purchase of a used filter and the autopsy revealed to me that the two body sensors are the ones that receive the flow after passing through the oil filter and not before, so this was the key for me to get the flow out of the filter cover that is flow not filtered by the filter and does not influence the already filtered flow.
Well still the use of 0.40(1mm) restriction before the two filters mounted in series not in parallel made sure not to divert too much flow to the double bypass filtration.
The series installation has a lot to do with it because in this way the flow and pressure are further reduced by having to go through a double filter.
It remains to be seen with the passing of the kms as the soot filters will be plugged, when is the optimal moment to replace the rolls of toilet paper.

By the way, one of the oil sensors measures low pressure so that in case of failure it gives the low pressure warning, the second sensor measures in the range of 2.5-3 bars and I don't know if it is the one that sends the dance at the entrance of each stage or is it due to engine revolutions. I did not go crazy to investigate exactly the procedure since with the autopsy of the used filter I saw that removing the flow from the cover I am not stealing already filtered flow, if I had chosen to use one of the pressure sensors to the flow output so if I had cared too much, I wouldn't have done it anyway.

It would have been curious to install measurement sensors to see cold and hot pressures, but I didn't do it because really reached 100° or more in idle speed 800 revolutions if there was a lack of pressure the oil light would come on due to lack of pressure
In two of my previous vehicles I had an oil pressure gauge and I never saw any variation using Frantz without restrictions of 0.40 (1mm).

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Did you know you can buy a billet aluminum oil filter cap with a threaded hole in the center? Several sources online. I had one on a Jetta.
Billet A4 Oil Filter Cap
I was looking and I didn't find for the EA 288 diesel, I only found for gasoline engines.
When I bought the used filter body, I modified the cover of this filter and put it on my A4, then I modified my old cover with the intention of putting it on my wife's EA 288 and it was not the same friction step. I started to investigate and There are different manufacturers of filter bodies, in the A4 it is Henqst and in the A3 it is Mahle, there are also other manufacturers and apparently each one uses its own thread pitch, this is not standardized.
I guess this is easy to do by a professional turner, it's a matter of finding the right one and who wants to make it.

Thanks for the warning, I reviewed them and it's all for gasoline engines.
Cheers
 
Very nice install, are you planning to extend oil change intervals? I run a Frantz on my engine, MotorGuard on the transmission and another Frantz as a fuel filter.:)
 
Very nice install, are you planning to extend oil change intervals? I run a Frantz on my engine, MotorGuard on the transmission and another Frantz as a fuel filter.:)
Thank you, I have decided to publish my installation so that more users have this knowledge, I will share more analysis experiences and sensations.

In cases of oil dilution it is clearly seen that the copper wearr ises together with the iron, I am aware that 2l of oil can help but this is not the definitive solution.
I will have to monitor the heating of the two filters to change when they are clogged.
I suppose that if the filters hold up well I will not change before 10,000km I will do an analysis and depending on the dilution I will decide, and if the percentage of diesel is at a level of 4-6%, I will possibly change the two rolls of toilet paper and continue up to 15,000km. By replenishing 2l of new oil, the diesel level will drop again.
 
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Some photos of the state of the oil in the two cars. Surprisingly, the oil still doesn't stain too much. For now they are warming up well, I will maintain the initial plan of enduring 10,000km, I will continue to observe the state. Apparently the A4 with ad blue and higher average speed stains much less oil compared to the A3 that does not use Ad blue and has a lower average speed
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That is awesome.., I put on an oil guard bypass filter-think they are called something different today… on a 2004 accord that bought new late 2004… ran extended oil drains up to 18-20 thousand brother has car now and still runs well.. he drives a lot less than I did when had vehicle has over 300 thousand in it now I believe
 
Here are some new gout samples. For the fuel level they do not work for me but to be able to see the soot load is very interesting. I have to do some long trips with the A4 next August approximately 7-8000km and during the trip I do not want to touch anything at all. I am almost sure that with my efficient driving profile the filters will hold without saturation but the fuel that accumulates will rise since on the way back it will have approximately 13-14,000km in total. My plan is to replace the 2 filters with 2l of oil that are needed to replenish, it does not cause me any inconvenience and the cost is approximately €5. In this way I hope to replenish new oil and lower the percentage of fuel, when I return from vacation I will send a sample to analyze and I will replace the 2 filters again.

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Here is a droplet sample from my previous change without using double bypass filter, as the previous samples were very good in terms of soot content, it was marked
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Today I replaced the two oil bypass filters on both Audis 2.0Tdi. Total 5400km on the A3 and on the A4, I have weighed the filters soaked in oil and each pair weighs approximately 1.5kg, so there is input of 2l of makeup oil. Next change of filters 5000km for the A3 and 8000km for the A4, an oil sample will be sent to analyze and I will continue without replacing the oil. I put some videos on YouTube, you can't upload videos here, I put the links. With this system and the filter changes I hope to be able to keep the fuel levels below 4%, it is still early but we will see the analyzes they reveal.




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Today I replaced the two oil bypass filters on both Audis 2.0Tdi. Total 5400km on the A3 and on the A4, I have weighed the filters soaked in oil and each pair weighs approximately 1.5kg, so there is input of 2l of makeup oil. Next change of filters 5000km for the A3 and 8000km for the A4, an oil sample will be sent to analyze and I will continue without replacing the oil. I put some videos on YouTube, you can't upload videos here, I put the links. With this system and the filter changes I hope to be able to keep the fuel levels below 4%, it is still early but we will see the analyzes they reveal.




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Very nice write up and info. Thank You sir 👍🍻
 
Back from vacation after 9,000 km, total oil level 14,000 km. I changed the two filters again from by pass and add oil between 1.5 and 2L to leave the maximum level and I will continue with the oil interval at least until the used analysis arrives and I will decide, whether I change it completely or follow the backup plan only filters. I took a sample to analyze before changing the filter because I want to see what wear and tear there is. Most likely the wear can be held back by the filters and only the fuel and soot levels will help me decide whether to go ahead or change the oil entirely.

The penultimate photo is from the change at km 5000. The last photo is from the 7000 km of the last analysis used without the double off-line filter system


According to the Polaris laboratory, the soot content was At first glance, the double bypass system does what it is supposed to do, but you have to remain calm and say that the installation has 1.5 liters more in it and after 5000 km another 1.5 liters have been added, the engine it has enjoyed 3l more oil compared to the 7000km analysis. That's a significant amount, but it also doubles the hours and miles.
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Back from vacation after 9,000 km, total oil level 14,000 km. I changed the two filters again from by pass and add oil between 1.5 and 2L to leave the maximum level and I will continue with the oil interval at least until the used analysis arrives and I will decide, whether I change it completely or follow the backup plan only filters. I took a sample to analyze before changing the filter because I want to see what wear and tear there is. Most likely the wear can be held back by the filters and only the fuel and soot levels will help me decide whether to go ahead or change the oil entirely.

The penultimate photo is from the change at km 5000. The last photo is from the 7000 km of the last analysis used without the double off-line filter system


According to the Polaris laboratory, the soot content was At first glance, the double bypass system does what it is supposed to do, but you have to remain calm and say that the installation has 1.5 liters more in it and after 5000 km another 1.5 liters have been added, the engine it has enjoyed 3l more oil compared to the 7000km analysis. That's a significant amount, but it also doubles the hours and miles.
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Very good work. I appreciate it 👍🍻
 

Here is my first analysis with the Frantz dual filter installation, I have not changed the oil because the % of soot and diesel are low, I have replaced both filters and the experiment continues.
 
I have a new by pass filter change on both cars.
I attach pictures of drop test,even the soot is around 0.1% ,according to my experience with previous analysis could deduce it.
I have samples of both cars and I will send samples to analyze the A3, the A4 I am still hesitating whether to send with 18.000km or wait in spring with 22.000km that seems more reasonable.as the soot does not worry me and neither the TBN & TAN the one that scares me the most is the % of fuel that I can not allow to exceed 4%.

As all this seems to be an experiment the most logical thing to do is to go from less to more to learn how everything is evolving.

For the cold winter months I have filled with 1.5l of 0w16 on purpose looking to lower the viscosity in hot as the oil temperature remains at 90 ° with peaks of 95 ° for the colder months and in spring will be replenished oil maw viscous hot.
 

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