Passat B8 air intake thoughts and mod

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smilie121
B4
Posts: 419
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?

smilie121
B4
Posts: 419
Joined: Wed Mar 30, 2011 4:53 pm
Passat model: B8 GT DSG 230bhp
Location: Loch Lomond

Re: Passat B8 air intake thoughts and mod

Post by smilie121 » Thu Jan 03, 2019 2:01 pm

Update

So after a bit of driving i have to say this is a must mod. Why didnt VW have this already in place???

- Better sound on higher revs and gear change
- More responsive
- Early days but i think i gained a few mpg - will be difficult to measure accurately. But noticed improved readouts at the end of a journey.

The engine noise is no louder at lower revs but when you boot it, theres a much improved sound - probably the best your going to get without putting serious money into it.

Remarkably i have not had to renew the duct tape and i have checked it often. Hats off to the manufacturers. Still i will be making a template and making a permanent seal.

You have to picture it with me here. To make a template I was thinking a bit of plastic roughly cut to size and silicon it on. After silicone has set i can remove it and should be left with a perfect match template to work with. If anyone has a better solution i am all ears.

Still intending on bunging up pipe so there is only one intake to see how it differs.

smilie121
B4
Posts: 419
Joined: Wed Mar 30, 2011 4:53 pm
Passat model: B8 GT DSG 230bhp
Location: Loch Lomond

Re: Passat B8 air intake thoughts and mod

Post by smilie121 » Mon Jan 14, 2019 8:26 pm

Update

Inside the air box is this guy

Image

Its there to prevent larger debris clogging up or potentially smashing through the air filter. I would imagine it would prolong the service life of the air filter also. However as the gaps are quite thin I was thinking it may choke the breathing capability. So I ran the car with it removed to see how it performs. Not sure I got any improvement in performance but induction sucking noise changed to a more pleasant sound.

So i have refitted it as with a slight mod - having cut every other bar

Image

New sound remained as far as I can tell. I had the wife drive up and down past me and the sound actually isn't that much louder than the stock quiet VW have managed to get unless your close to the front of the car. It's kind of sporty but its more noticeable inside the car than out. I think this is great as I don't want the car snorting around and just wanted a bit of grunt when my foot turns to lead.

The cost of an air filter is £16 for a Bosch. I see Piper cross and RamAir have non oiled ones for £35. They all have their claims for extra ponies but if its better again at breathing it must gain something. I remember reading and watching a where with the use of a dyno they discovered cone filters, stock filters and no filters did virtually nothing to a Leon TDI (and i think something else). Is it still the same now with the technology changes to the engine? Is it worth trying for the sake of the cost of 2x air filters vs saving on next few services?

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ray112
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Passat model: B5
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Re: Passat B8 air intake thoughts and mod

Post by ray112 » Mon Jan 14, 2019 9:01 pm

If there was no performance gains even without filter at all, then common sense says, that any kind of filter won't give away improvement. Even with technology improving. I would like to believe that bigger turbo might need different filter, due to increased volume of air going through, but there is usually increased size of intake pipes, intercooler and exhaust. On everything stock, only thing you need is to keep standard filter clean. I'm replacing mine every 10k miles together with oil change and giving a quick clean with vacuum cleaner somewhere in middle of service intervals. I would like to think that only difference what performance filters will give, is a bit of noise and more dust getting through, which can cause problems with MAF sensor in future.

smilie121
B4
Posts: 419
Joined: Wed Mar 30, 2011 4:53 pm
Passat model: B8 GT DSG 230bhp
Location: Loch Lomond

Re: Passat B8 air intake thoughts and mod

Post by smilie121 » Wed Jan 16, 2019 8:44 pm

No arguements there - oil on the maf and particles getting through were a concern when I got a green panel filter for my very first W reg passat. But when I went back to a stock filter I noticed a slight difference on acceleration on 2nd gear and higher - say like 20-40mph or 30-50mph.

The video on youtube was about a Leon 1.9TDI. So a few years ago. I was wondering if it would make a difference on a more modern engine. And for the cost of 2 filters I am entertaining it, non oiled version of course.

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