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Restrictive air cleaner

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Restrictive air cleaner

Postby Powertruck31T » Tue Aug 04, 2015 10:27 am

I've just run a couple of tests on my setup testing how restrictive the air intake system actually is on the 4jg2 engine. I have modified my airbox lid so it takes a KN 3" filter and made up a 3" pipe from the airbox to the turbo where it tappers down to 2.5". I haven't modified the inlet into the airbox at this stage just because I wanted to see how it would perform. After 200km of driving the restriction gauge has already recorded 25" H20 which is way to high. This is only on 11psi of boost. So if it's pulling this type of restriction with a modified setup what do they do in standard form with a stock filter and piping? I would hate to know. I will open up the airbox with a larger 3" pipe and run the test again to see what happens.
With this type of restriction its robbing hp and causing higher EGT's not only that but at 25" it will pull oil out of the turbo.

Will keep you posted when I modify the airbox.
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Re: Restrictive air cleaner

Postby geeves » Tue Aug 04, 2015 3:26 pm

25 inch of water [4 °C] = 0.903 182 295 67 pound/square inch
Thats not really a lot.
Can you as a test make a short pipe with the pod filter mounted straight on the turbo and do the same measurement?
Sanding your knuckles before starting work can help. That way you cant skin them
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Re: Restrictive air cleaner

Postby Downhillnz » Tue Aug 04, 2015 5:16 pm

I have the same issue. I notice a big difference putting the piping to the airbox on vs just having a pod filter on the front of the turbo. I think opening up the airbox will help heaps. Post up your results of a 3 inch pipe
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Re: Restrictive air cleaner

Postby Powertruck31T » Thu Aug 06, 2015 6:00 am

Geeves in turbo terms 25" is a lot. The gauge stops at 30. 6-10" is acceptable as it allows room for when the filter does clog up. This was with a modified inlet pipe aswell using a K'N filter in the box so I don't know what a factory system would do but would be interesting to see the results.
Just as a test I removed the airbox lastnight and just ran the filter attached to the lid. Straight away I could feel the difference EGT's droped by 80 degrees was a lot more responsive. This was a good hard pull up a steep hill. When I checked the gauge it hadn't even moved off the seat. So its pretty fair to say that the factory airbox intake is where the restriction lies. This was only on a moderate 10-11psi aswell so once the motor is run in and I can get some fuel into it I'll be pushing the boost up to 15 which would only make the restriction even worse on a stock airbox.
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Re: Restrictive air cleaner

Postby geeves » Thu Aug 06, 2015 10:52 am

At 15lb boost and 4k revs your moving the same amount of air as a same size non turbo engine pulling 8k
I dont have access to these testers but will have to agree that removing the inlet system after the aircleaner on the ubs55 when I fitted the snorkel made a huge difference. Changing to a finerfilter improved things as well but mostly because there was more breathing space around the filter.
Havnt done much to the ubs69 except fitting a kn pod inside the airbox as the snorkel was already fitted. Im still running a 2 inch exhaust so gains will be limited
Sanding your knuckles before starting work can help. That way you cant skin them
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Re: Restrictive air cleaner

Postby Downhillnz » Thu Aug 13, 2015 12:40 pm

I've solved the issue. I always thought it was the air filter itself. Its the air box crap around the airbox.

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Re: Restrictive air cleaner

Postby geeves » Thu Aug 13, 2015 2:39 pm

thats a big piece of pipe on the side. Does it feed a snorkel?
Sanding your knuckles before starting work can help. That way you cant skin them
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Re: Restrictive air cleaner

Postby geeves » Thu Aug 13, 2015 2:39 pm

the other option would be the apollo style airbox from kn
Sanding your knuckles before starting work can help. That way you cant skin them
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Re: Restrictive air cleaner

Postby Downhillnz » Thu Aug 13, 2015 3:14 pm

geeves wrote:thats a big piece of pipe on the side. Does it feed a snorkel?

It doesn't yet. But it will before it goes for its next adventure.

I removed all of the weird plastic boxes and welded plate over the holes.

Makes a massive difference vs stock
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Re: Restrictive air cleaner

Postby danz20 » Mon May 01, 2017 6:45 pm

Mines gay efi atm and ive fitted pod filter
And still noticed big differance when ive removed the lid
To the point ive now lost it :(
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Re: Restrictive air cleaner

Postby brentpham » Thu Dec 13, 2018 8:29 pm

Downhillnz wrote:I've solved the issue. I always thought it was the air filter itself. Its the air box crap around the airbox.

Image
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Big solution, thank you
I choose you
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Re: Restrictive air cleaner

Postby Brinky » Fri Dec 14, 2018 7:32 am

Moving to the K&N and snorkel made a huge difference to my Mu. I thought you only had Amigo's in the states, not Mu's. Is your a turbo diesel as well? Can't be many of those over there. Cheers Paul
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