Air Intake fix?

More
01 Nov 2012 12:35 #1 by dandjcr
dandjcr created the topic: Air Intake fix?
Forum Home > OKA Maintenance > Air Intake fix?

OKA4WD.com
Administrator
Posts: 412
From Rob Williamson:

Has anybody been able to modify the noisy air intake from behind the drivers head and re-locate it to a better position....would like to find out a suitable way and improve my OKA.
May 2, 2010 at 12:06 AM Flag Quote & Reply

OKA4WD.com
Administrator
Posts: 412
From Michael Hession:

I read in a newsletter, I think, some time ago where a member turned the exterior cover, over the air intake, through 90 degrees. Thus the intake was now facing the rear of the vehicle and this made it a lot quieter.
May 2, 2010 at 12:08 AM Flag Quote & Reply

OKA4WD.com
Administrator
Posts: 412
From David Ribbans:

I took the plastic cover off the air intake pipe behind the drivers seat and all the foam insulation inside had disintegrated.
I packed it with some more accoustic foam (from Whitworths the boating people) and then sealed the whole thing by surrounding it all with more foam. That should reduce the interior noise a lot. Generally, covering all interior exposed metal work with thick foam or similar helps with noise reduction, even those areas already insulated like the engine cover.
I have also seen a taller snorkel type attachment on the outside to raise the level of the air intake, like a truck, as I beleive that is where the much of the noise originates (90mm storm water pipe fits). The opening can then be reoriented to to the front, which should also help air flow into the intake.
Pointing it rearwards might reduce the noise level but intuitively it seems wrong and might inhibit airflow rather than help (ie reduce the air pressure outside the intake, like airflow over an aircraft wing reduces pressure above it).
May 2, 2010 at 12:09 AM Flag Quote & Reply

OKA4WD.com
Administrator
Posts: 412
From Peter_n_Margaret:

Hi guys,
I've heard complaints about this problem before.
I can't tell you why, but our #196 is standard in this department (except that I have added a vacuum gauge so that I can monitor air cleaner condition) and it is NOT noisy!
Peter
May 2, 2010 at 12:11 AM Flag Quote & Reply

Hal Harvey
Site Owner
Posts: 510
>> a member turned the exterior cover, over the air intake, through 90 degrees. Thus the intake was now facing the rear of the vehicle and this made it a lot quieter. <<

I think that was Collyn Rivers. He does seem to know what he's doing.

Sort of on the same subject, I have a set of Bose noise-cancelling headphones that I often use. They have an on/off switch that, when switched on, eliminates about 75% of regular noise (yes, you do have to be wearing them!). They can be used alone or plugged into the stereo. They make an OKA frighteningly quiet - you'll need a tap on the shoulder if somebody wants to talk to you, and you do tend to watch the gauges a lot more because there are probably a few noises you just won't hear!

I got a headphone jack put in the dash and wired such that when the headphones are plugged in, the speakers are cancelled out. It's obviously great for when you're driving alone, but also when you have a passenger who's asleep and doesn't want the music blaring, you can just plug in the headphones, have whatever volume level you want, and they get nothing; especially if they're wearing their own Bose headphones, switched on and unplugged.

Bose cost heaps more than most, so I started out with Sony's "equivalent". The Sony version was fine on planes, but didn't work in the OKA; the noise reduction would 'pulse', and they also didn't knock out as much noise as the Boses do. Fortunately I lost them somewhere, so I replaced them with Bose, and never looked back.

I'm keen on the general noise reduction thing, but have my doubts about how much more can be achieved with more insulation. When we've done out best, we'll still be surrounded by three big sheets of flat glass, which are really bad for noise level. They're flat for good reason, but all regular cars have all curved glass for a(nother) good reason.
--
Hal

May 2, 2010 at 12:13 AM Flag Quote & Reply

OKA4WD.com
Administrator
Posts: 412
From David Ribbans:

I have fixed the air intake noise problem on our Oka 2 ways:
I've insulated (actually over-insulated) the air intake pipe behind the drivers seat (refer previous post),
and
I've fitted an extended snorkel up and forward over the drivers door so the air intake is now along side the sun visor. It uses standard 90mm PVC piping.
This has shifted the source of the sucking noise to the front and it has all but disappeared (except when the window is down).
Over the past 8,000 kms, it's had no adverse effect on fuel consumption and might even have improved it a tad, due to the ram-air effect.

David
May 2, 2010 at 12:15 AM Flag Quote & Reply

OKA4WD.com
Administrator
Posts: 412
From David Hallandal:

The OKA has two air filters - have you replaced both of them?

I have no excess noise at all. The droning you can get when the filters are getting blocked.

I have insulation around the drop pipe but believe this is standard, try removing the outer filter only and go for a quick test drive and see if there is any difference.

I am starting to believe the OKAs may have too small an air box, not allowing enough air through and have gone down the path of larger replacements.
David
May 2, 2010 at 12:18 AM Flag Quote & Reply

Hal Harvey
Site Owner
Posts: 510
My own air intake is standard and has no sucking noise. Below is #155 with a distinctive forward-facing modification;



and the new NT air intake;



and an NT intake fitted to #137...


--
Hal

May 2, 2010 at 12:50 AM Flag Quote & Reply

Dave and Pauline Gray
Member
Posts: 84
Hi all i have replaced the insulation around our interior inlet pipe and it improved the interior noise marginally but i do recall reading on the old site that a member had rerouted the pipe work to the rear of the vehicle a model similar to yours Hal and the effect was extremly good, one of the mods on my to do list. Cheers Dave
May 2, 2010 at 9:28 AM Flag Quote & Reply

Paul & Sue Crompton
Member
Posts: 44
Hi Guys from Paul and Sue
My snorkel intake is reversed (Collyn Rivers old Oka). I do not notice any air intake noise in the cab but when I first purchased the Oka I did insulate around the PVC pipe and I also insulated inside the cab. Collyn had already insulated underneath the engine bay lid. I cannot comment on how noisy it is compared to other Okas as this is the only Oka I have driven but it is reasonably quiet on the inside as it is possible to have a normal conversation without raising your voice. If I wind down the windows, I certainly can hear the noise from everything so I guess the insulation is helping. I can also confirm that the noise cancelling headphones work reasonably well on the tractor as you certainly notice the difference when you switch it off. I have yet to try them in the Oka. Cheers Paul.
--
Paul & Sue Crompton

May 2, 2010 at 3:09 PM

David and Janet Ribbans - Oka 148
Oka148 profile here.
Visit our technical and travel blogs: here.

Please Log in or Create an account to join the conversation.

Powered by Kunena Forum