Passat B8 air intake thoughts and mod

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smilie121
B5
Posts: 467
Joined: Wed Mar 30, 2011 4:53 pm
Passat model: B8 GT DSG 230bhp
Location: Loch Lomond

Passat B8 air intake thoughts and mod

Post by smilie121 » Sun Dec 30, 2018 1:15 pm

So a few days ago I decided to have a look at the air intake and see if anything can be done - remembering Desertstorms "ram" air intake mod on the B5

Links to full sized pictures
https://i.ibb.co/KrGH3mn/air01.jpg, https://i.ibb.co/wcPCV3N/air02.jpg, https://i.ibb.co/crqryR7/air03.jpg, https://i.ibb.co/hZ6FLsd/air05.jpg, https://i.ibb.co/sPM86JL/air06.jpg, https://i.ibb.co/4KRyghr/air07.jpg, https://i.ibb.co/KV73G7Q/air08.jpg, https://i.ibb.co/Vt23pWj/air09.jpg, https://i.ibb.co/P468C6X/air10.jpg, https://i.ibb.co/VmKGj07/air11.jpg, https://i.ibb.co/Rh53sFG/air12.jpg, https://i.ibb.co/d4qTgGF/air13.jpg

I have a Passat B8 Estate 190 DSG GT - your innards may differ

Looking at the air box I can see there is a connecting piece to a long plastic piece at the rear top of the radiator - unsure of its given name. Top cover removed - held on by 2x 25 torque screws and a plastic clip dead centre at the rear.
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I drove the car with the top cover removed to hear what it would sound like. Induction noise was quite different with a nice whooopppfff (sucking sound) on gear change with a bit of turbo use. Other sound on rev range not bad. However at lower revs it was rattly diesel.

The left hand side has a rear piece open, obviously designed to fit an additional air box like seen in some large engine Audi's. However the left side has an air inlet from the front grill where as the right hand does not. To remove you will need to loosen the piece that feeds the airbox (just clips) on the right to remove. Now you can see the front grill has 2 air feeds
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But the plastic piece, now removed, only has one air intake
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So the air thats being rammed in is not efficiently being directed to the air box. Mosty is hitting the engine. So thoughts are to tape this up and see if makes a difference. I could also cut out the blanked off piece and blank off the left side so there is a more direct flow. So I thought I would try it in stages.

I double and triple duct taped, both from the outside and inside - heavy clean required first. Took it for a minor run worrying about the possibility of melting tape or it being sucked off into the box
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Hmmm, feels more responsive. I stopped several times to check the duct tape and it held, all the way up to the legal speed permitted on UK roads. So now to try cutting out the blanked bit.

I wouldn't get a dremel cutting disc in there and besides, they just melt plastic furring itt up rather than cut through. So i decided to drill it repeatedly with a large bit, taking care of most of the work, then grind down with a metal wheel on a dremel, a stanley blade where needed and a bit of 500 grit to smooth any rough edges. Took about 15 - 20 minutes.
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Finished and pretty smooth, despite the way it looks
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Re-installed
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So out again. A bit louder induction wise than stock but no way as much as having the top cover removed and no terrible noise on lower revs. Definitely more responsive thanks to it breathing easier. So like DesertStorms original discovery, its a worthwhile mod to consider. And probably 1 extra horse to add to engines output :D

The tape is temporary as no way it would last. I think the next way forward is to put a temporary block right of the centre so it only has the right air intake and try to measure it again. That way I can always revert to having the two intakes and just make a plastic blanking piece for the left side instead of the duct tape

Thoughts / Suggestions?

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