Diesel Air intake noise

[boatbuilder]

Just went for a test drive in my van and the first thing I noticed was the engine noise coming from the left rear pillar where the air intake is. I've fitted the oval silicone pipe from Brickwerks in there -
Is there any way to reduce this noise? Its pretty deafening if you're sitting in the back... I have a 1.9d AEF engine fitted...

[dave friday]

What's the rest of the intake system( snorkel onwards )?

[clift_d]

What's the rest of your air intake setup? Have you replaced any of the other hoses? Do you have the original JX air filter fitted?

This is not an uncommon problem on diesel conversions, and my understanding is that you'll get the quietest results with the original air filter & enclosure, and a properly sealed air duct to the snorkel in the corner.

[boatbuilder]

I have all of the original setup except I replaced the old holey snorkel tube with the brickwerks silicone one.
I think one of the little rubber mounts needs replaced and the flexible link at the filterbox is held together with duct tape.
Not convinced that those would make a massive difference...or maybe I'm wrong?

[clift_d]

Duct tape doesn't sound so good.

Brickwerks do a replacement silicon section for the centre of the 068129623E intake hose from the base of the snorkel to the filter box - part 6 in this diagram.

[boatbuilder]

Looks like thats for the td engines. Mine is using the 1.6d fittings...

[RogerT]

Did you squeeze on the thick rubber "band" thingummy (part 11 in the aforementioned diagram? This plays a part in keeping the walls of the silicon tube you fitted away from the walls of the bodywork section it resides in. That should dampen the sound somewhat. You're probably right about the rubber mounting for the plastic top piece. That will also provide some sound isolation. Getting the silicon tube to stay on the plastic top piece was quite a challenge- I used a big jubilee clip in the end. Others have used a zip tie through a hole punched though silicon and plastic.

[colinthefox]

I lined the cavity with a layer of rubber conveyor belt which reduced the noise reaching the back seat passengers a lot. Replacing the rubber bellows with silicone flexible air ducting was another improvement. Finally I scrapped the plastic elbow and replaced with a large rubber elbow which I could seal properly. I renewed the anti vibration mounts and made sure that none of the components were in contact with the bodywork anywhere. This all took ages but was well worth the effort.

Whatever you do, make sure that you leave a drain hole for any water that gets in the air intake.

[boatbuilder]

Thanks fellas.
Yes I used some cable ties to hold the oval silicone tube up on the plastic intake.
Looks like I have some more work do do!
Colin did you put the conveyor belt material right in behind the oval duct? How did you get it to stay there? Seems like a very awkward area to work in.
Pictures would be great if you have any!


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[colinthefox]

Thanks fellas.
Yes I used some cable ties to hold the oval silicone tube up on the plastic intake.
Looks like I have some more work do do!
Colin did you put the conveyor belt material right in behind the oval duct? How did you get it to stay there? Seems like a very awkward area to work in.
Pictures would be great if you have any!

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The conveyor belt was fixed with stainless self tappers from inside the van. It covered as much as I could of the face between the duct and steel behind. And yes, it was a pig to get in there.

In my thread on BY there is a picture of the air duct that I made up. It's rigid PVC 90mm telecoms ducting, heated with a hot air gun and squashed to an oval section, then heated again and bent slightly to fit the curved space without touching the sides. It also has to be curved to get it in place through the top vent, then rotated. The key to this duct is that it shouldn't touch the sides anywhere. A flexible pipe will pulsate against the bodywork. It also has to be sealed to the elbow at the bottom.

Pedantic? Exactly. That's how you get it quiet.

[boatbuilder]

Not much space in there at all! My oval silicone tube definitely touches both sides of the cavity. I suppose I could wedge a sheet of rubber between the tube and the metal but it'll further compress the oval.

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