Air cleaner for 4.2TD

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Michael
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Air cleaner for 4.2TD

Post by Michael » 27 Aug 2014 14:48

Dagse Kerels

Ok so I have bought myself a snorkel for my patrol and am planning to install it over the weekend, but before I start I just want to hear what your opinions are on the air cleaner.

My main objective for the snorkel is to get the engine to "breath" as easily as possible. I really love my Patrol and I want to do thing right the first time.

I would like to hear what air cleaner boxes the other 4.2TD members have? I currently have an aftermarket Donaldson, but not sure which one exactly and I have no idea what the CFM rating is on it.

The other problem I found was that my current Donaldson does not seal where you open it to replace the filter...... this I found out when I serviced it over the weekend which means the snorkel will not be as effective as it should..... not even mentioning what can happen when I submerge the engine in a river crossing.
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Re: Air cleaner for 4.2TD

Post by marakasmalan » 27 Aug 2014 15:01

So, the question is on which side of the filter did it not seal properly.

Secondly, if it was kept to the standard confiduration, it most likely would have sealed properly.

Maybe just keep it standard? Simple, and cost effective?

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Re: Air cleaner for 4.2TD

Post by Peter Connan » 27 Aug 2014 15:04

Donaldson is good, but I am not sure what CFM you need. Using some figures on the net, I reckon 500ft/m should do the job, but the bigger it is, the lower the pressure drop will be.

The air should flow from outside the filter inwards, so the air leaking in should also go through the filter element. I would not be too worried about the gap.

Before doing a trip in which you expect a lot of dust or deep water crossings, tape the gap with duct tape...

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Re: Air cleaner for 4.2TD

Post by Tinus lotz » 27 Aug 2014 16:10

Give bogey man a call he has a contact that sells aircleaners housings ect let him post a pick or two of the gq setup I was very impressed :salute:

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Re: Air cleaner for 4.2TD

Post by bogeyman » 27 Aug 2014 18:20

I have 2 photos of the installation. Some breather pipes were not connected yet.

I use Donaldson type aircleaners because dirt is not welcome in any engine. Never. Performance might suffer but the engine will last.

This is on the gq with the transplant tb45e engine.
I used the thumbsuck selection method and used a 90mm outlet standard Donaldson cyclone air cleaner. It just fits in under the bonnet and I custom built the bracket for mounting onto the wheel well. The only drawback is that I have to loosen the mount clamps to get to the cartridge for cleaning.

The positioning made for minimal bends and virtually straight pipes in and out. The air gets sucked in from the original hole in the fender , so water does not easily gets in there. Also , the big inlet pipe is at an angle and with low engine speed , water will most likely not get drawn in. On this type , all the air is drawn in at the inlet pipe , so snorkel will work.

The change in pipe configuration played havoc with the engine management. I used the same air mass sensor housing and sensor , but the air flow patterns made no sense to the sensor.
Two hours of remapping by Maus and all was well again.

Those filters are used by most big engines. Look at the big generator sets and air compressors as well as most industrial earthmoving machines.
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Re: Air cleaner for 4.2TD

Post by Michael » 28 Aug 2014 08:33

Dankie vir julle input

Markus, ek het ongelukkig nie die standaard filter setup nie, ek het die Patrol so gekoop met die huidige Donaldson filter. Ek het self al gewonder oor die ZD30 se filter setup, maar het bietjie opgelees en dit klink my hy is net so bietjie te klein vir die 4.2 engine....... maar ek moet se dit was getoets op n ou se 4.2TD wat 150kw op die wiele maak so sy engine sal meer lug nodig he as myne. Daar is wel n ander ou wat n ZD30 air boks gevat het en hom bietjie ge mod het sodat sy inlet en outlet pyp net so groot is soos die snorkel sin wat dalk ook kan werk?

Pieter, ja ek sal defnitief nie stof in kry nie, want die gedeelte wat nie seel nie gaan maar net lug laat in kom vanaf die engine bay.
My enigste problem met dit is dat dit warm lug gaan wees en ek wil so veel as moontlik goue lug in die engine in kry. Veral met n turbo engine sal n relatiewe klein lek redelik baie lug laat in kom as die turbo onder boost is. Ek moet se ek hou van my huidige Donaldson en gaan eers kyk of ek hom nie kan modify en reg maak nie, sal kyk of ek sy serial nommer of iets kan kry om sy CFM te bepaal, maar ek het ook gedink ek het so 500 - 550CFM nodig vir my engine

Christo, ek hou van jou filter setup! lyk baie netjies en lyk of hy 100% sal seel in die geval van diep water. My enigste problem is spasie...... ek het heelwat minder spasie onder die bonnet soos dit my lyk. EK sal later vandag gaan fotos neem van my setup dan kan jy my dalk jou opinie gee oor kleiner Donaldsons...... ek hoor wat jy se oor die performance vs skoon lug en dit is n moeilike een.
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Re: Air cleaner for 4.2TD

Post by ricster » 28 Aug 2014 10:43

I cant recall when I was at your place that one evening if we looked at my setup on my 4.2... :think: .... But my personal feeling is that the ZD30 airbox will work, but is not the ideal airbox for the extra 1.2L engine capacity difference plus the extra air supplied by the turbo.

Space int the engine bay is VERY limited, especially if you have a dual battery system fitted in the engine bay. I have recently removed the dual battery to the back of the Patrol and now seem to have heaps of space. The problem now is to find a filter box and filter that can give the least restriction. For me the ZD30 airbox works great when the filter is just replaced but after about 2000 odd Km it isn't the same anymore. I also as an emergency have a K&N sponge airfilter that fits into the ZD30 box and if I use that then my Iron Maiden pounces like a wild animal, however when the oil that one sprays on the foam becomes a little dry and dirty ( again after a few thousand Km ) one can feel the restriction. The sponge surface area in way less than a paper filter and the oil on the sponge filter looks like a flattened cow putty stuck to the sponge. reducing the surface area by probably 40 - 50%. Cleaning the sponge filter every 800- 100Km is just NOT practical.

The Donaldson filter would be the best bet then for me, but I also don't want to move things around in the engine bay to accommodate the filter housing. My turbo is a high mount ( sits level with the head or above the exhaust manifold ) so would also like to keep the number of bends to an absolute minimum.

I was thinking of finding an affordable and easily bought airfilter that can handle the maximum airflow required by the 4.2 turbo motor. This can either be a flat filter or tube/cyclonic filter, and then build a steel airbox to suit the filter and the space available in the engine bay. A bit of insulation to assist with minimal heat transfer can be done too. The question is what is better.... cyclonic or flat filters.... bearing in mind that the 4.2 diesel NEVER revs higher than 4000rpm ( at 4000rpm the valves sound like they want out of the engine), so its more about the volume of air than the speed of the air going through the filter.... please correct me if I'm wrong on this.

If Peters calcs of 500ft/m are correct where does one start to find a filter with that cfm and sizes, so one can start eliminating the shapes and sizes that won't work?
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Re: Air cleaner for 4.2TD

Post by Peter Connan » 28 Aug 2014 12:48

Cedric, i don't know much about air filters and how they are rated, but I know a thig or two about gas flow.

The formula I used above to get to 500CFM is basically just the engine capacity, converted into cubic feet, divided by two (as it's a four-stroke engine),multiplied by maximum RPM (I used 5000), multiplie by an arbitrary volumetric efficiency (I used 90%, which i think is very high for this engine) and multiplied by 1.5 (for the turbo).

Your idea of fitting a larger filter is sound, but:
You can force a vast amount of air through a very small hole, but the result is a loss in pressure. To put it another way, the more air you shove through a specific filter, the lower the pressure will be between the filter and the turbo inlet, and this lower pressure will result in less air going into the engine, which then results in less power.

But of course the filter is only one of the restrictions in the system. The inlet pipe or snorkel, the pipe from the filter to the turbo inlet, the pipes from there to the intercooler, the intercooler itself, the pipe between the intercooler and engine and the inlet manifold all play a role, and it is quite possible that improvements in other areas can result in less need for a larger filter.

In other words, there is little point in using a massive filter if for example the intercooler has less flow capacity. Or the piping is very convoluted. The sum of the inverse square of each restriction gives the inverse square of the total capacity.

Now to throw another spanner in the works, the air pressure after the turbo is higher,thus one would assume that the intercooler and piping here could be smaller, but the temperature of the air is a lot higher at exit from the turbo, and as a result the volume is considerably higher than expected. How much so depends on the temperature and pressure reached, which will depend on the actual installation.

Now WRT pancake or Donaldson: the Donaldson's big advantage is that the air is cyclonically pre-filtered, thus most of the dust and larger particles never make it into the filter element itself, and thus it lasts longer and gets blocked more slowly. Now comes the trick: the faster the air velocity, the better the cyclone effect gets rid of the dust (but the only way to get the air moving faster is to restrict the flow), thus a bigger filter unit might not last as much longer as you expect.

The GQ's have a pancake filter with a cyclonic pre-filter, which in theory does the same thing as the Donaldson. I would recommend that if you decide to go that route, that you get one of these units. It will reduce the total air flow, but will reduce maintenance.
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Re: Air cleaner for 4.2TD

Post by marakasmalan » 28 Aug 2014 14:15

Peter Connan wrote:The formula I used above to get to 500CFM is basically just the engine capacity, converted into cubic feet, divided by two (as it's a four-stroke engine),multiplied by maximum RPM (I used 5000), multiplie by an arbitrary volumetric efficiency (I used 90%, which i think is very high for this engine) and multiplied by 1.5 (for the turbo).
Yes, well known formula, called "Peter's Rule" - write that down!
ricster wrote:K&N sponge airfilter
AFAIK that is a racing filter. Horses for courses. I think a racing filter is designed to perform optimal for a race. Furthermore I did not notice a lot of amateur rally cars with K&N filters, so I reckon dust is not exactly it's strength. Thus it makes sense that it is not very practical in application on a recreational 4WD.

When manufacturers develop an engine, the filter system is not something that is quickly decided upon the Friday afternoon before release. During a long production life, any shortcomings become evident and can be rectified. Ingestion of fob or dust into an engine is not by any means desired. Furthermore, the air/fuel mixture is an important factor for the engine efficiency and longevity, as wrong mixtures can have adverse temperatures as an effect causing underperformance an in some cases substantial damage.

This is why I am always in favour of the standard setup, at least in concept/specification - be it donaldson/GUD/OEM.

What does interest me, is if the manufacturers setup did in fact take into account the use at high altitudes. The use of an altitude compensator on the TB42S patrols hint towards this, but if the range actually includes altitudes of up to 3000masl as we have in Lesotho remains an open question.

The fancy crowd with EFI have the ECU regulating the air mass/pressure as opposed to mere volume control. I think using "Peters Rule" will leave enough redundancy for adverse barometric conditions, but is there any way to determine the optimum diameter for the plumbing?

Thanks for a very interesting discussion.

Useless factoid: The CFM for a Rolls Royce Merlin engine is ± volume of a double decker bus/minute!

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Re: Air cleaner for 4.2TD

Post by ricster » 28 Aug 2014 14:28

Thanks Peter !!

My theory then may not be a bad plan then afterall..... if I look at it this way.....
1) The current Safari snorkel is going to offer restriction. Irrespective of brand name ( some may have a better coefficient than others )
2) Where the snorkel enters the engine bay ( currently ZD 30 box is fitted there ), if I change the pipe size from, if I recall correctly, 50mm dia (2") to a 3" stainless pipe with a soft bend to then enter the airbox. Here restriction and pressure should be reduced??? as airspeed is reduced.
3) If the airbox, as per the VERY rough sketch, could keep the pressure drop between inlet and outlet as low as possible, here I'm assuming the bigger flat filter would give a good filtering and pro-rata pressure drop.
basic airbox concept.jpg
basic airbox concept.jpg (192.66 KiB) Viewed 2664 times
4) A 3" outlet from the airbox straight into the turbo. Minimal restrictions and pressure drop. My turbo is a high mount so straight could be possible
5) Through the turbo and out via 2" gentle curve leading into the top mount large intercooler. ( would it be better to have this as a 3"???)
6) My intercooler outlet is a straight down pipe, again 2" directly into the inlet manifold
5.jpg
5.jpg (221.37 KiB) Viewed 2664 times
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