Debottlenecking intake manifolds Passat 1.9 TDI AWX/AVF

Hello everyone,

After reading the relevant article, I understand what 'de-throttling' involves. However, I don't have a way to measure the pressure inside the air filter housing. Therefore, I cannot make a statement about whether de-stroking the engine on a Passat with an AWX/AVF engine would have any beneficial effect.
The Passat's flat intake manifold is located behind a section of the radiator grille that faces forward. In my opinion, this makes sense because it helps prevent excessive spray from being sucked in when driving in the rain. However, this leaves only a relatively narrow 'intake slot' open at the bottom. The air entering there should be the air that previously flowed through the radiator.
Are there any practical experiences available regarding whether it's worthwhile to do anything here? And if so, what would be the best things to change? Unfortunately, I haven't found anything specific about the search .

Best regards, Matthias.

PS: For those who can't imagine what a 'Passat' air intake looks like, I will provide pictures.

Quote:

The air flowing in there should be the air that previously flowed through the radiator.

I can't imagine that, no matter how hard I try.

That would be almost as stupid as completely blocking the air intake to the air filter and letting the turbo suck air directly through the plastic.

Explicit hot air coming from the water cooler is an absolute no-go.

m;

Hi,

As far as I can see, that's how it is. That's why I created this topic. Or maybe I'm blind as a bat.
Attached are a few pictures.
The area highlighted in red shows a 'closed grid'. Behind it is the intake manifold, which can be seen in the 2nd [image/diagram/etc.]. The image should be clearer.

Could it be that it's drawing air from above the radiator?

It's quite obvious with the 3C, because it has a grille that sits ON top of the bumper.
http://i20.ebayimg.com/02/i/000/8a/60/b37e_1.JPG

m;

Okay, as you can see from the pictures, the area in front of the intake manifold is closed off (with a solid grille). The area behind the actual, open grille is obscured by the radiator/condenser.
It's difficult to say exactly what the airflow is like. Perhaps air is also entering from the engine compartment. In any case, the supply of fresh air isn't exactly abundant - at least, that's how it seems to me. Therefore, it is very interesting to know what other drivers of the 3BG think about it.

Best regards, Matthias.

Hello,

Since I have the same vehicle, I am also interested in finding a solution.

I'll check to see if we had that in development as well.
As far as I know, it draws air from the front.

Best regards, Andi.

@Dieselmartin, I haven't gotten around to discussing the AGR system yet, but I still need to do that.

It's located above the radiator, just like on a Golf, for example, but it's on the other side. The remaining part serves as a splash guard, and it's essential!

Matthias,

Goelffs (likely a typo, possibly "Golfs") from model years 2000 to 2004 (inclusive) may have a problem where water is drawn into the wheel wells.

m;

Okay, so I'm also chiming in as someone who drives a 3BG and a V6. My intake is the same as yours at the top, except that the closed grille you have is a real grille on mine, so it actually sucks air through. I have no idea why yours is blocked. Now, mine also has an opening in the air filter box, pointing directly downwards, probably towards the wheel well.

"This intake nozzle should be the same as mine. It's attached to the lock carrier and can be removed with 2/3 of the screws. As far as I remember, the nozzle runs above the radiator and definitely does not draw air through the radiator." He probably takes a detour to get air through the grill, but not through that specific grate.

You're not talking about an opening at the bottom, maybe you should check to see if one exists.

So, the process of "de-throttling" for your car might look like this: Install the air filter box (I'm not sure if the top part of the air filter box, which includes the connection for the mass airflow sensor, is the same...) and the grill from the V6 model (or simply open your existing grill). Now you have the problem that it might already be inhaling quite a bit when it rains, which it might not be doing now.

So, as Mr. Antje already mentioned, the V6 version draws air through two intake passages, while the 130 HP PD model only uses one.

Okay, so I won't be doing anything with the grill, but I'll try to somehow incorporate the lower part of the air filter box. If that's not possible, modify an old air filter housing.

@Mr. Antje
According to the documents, the intake manifolds are actually the same for the V6 and 4-cylinder engines.
I've already experienced that myself. Thanks to the nice package, it has to be removed in order to change the glow plug brine.
Anyway, the top part of the proboscis extends further forward than the bottom part, so there's already a slit at the bottom, as you said.
However, the slot above the radiator is still quite narrow. At least, it was wide enough that leaves and cigarette butts ended up in the air filter box. It's now difficult to say exactly what proportion of the air entering the intake manifold is flowing through the slot. However, we agree that the solution shown in the images is not optimal.
Of course, the fact is that the V6 version would also suck in spray. I don't think that a small hole in the air filter housing would prevent the air filter from being fully saturated.
It seems clear that the V6 solution is technically superior.
The question now is whether, in my specific case, there is actually too much negative pressure in the air filter housing, making it worthwhile to change the airflow configuration.

I don't understand your point about why someone should use a different air filter housing. You can actually make the process yourself.
What I'm thinking is that I could cut away a bit from the underside of the trunk to widen that rather narrow slit.
However, the use of an open grid is unlikely to be problematic. Because the V6 engine doesn't seem to have any problems with it.

Best regards, Matthias.

Okay, back to the topic:

The V6 TDI engine has two intake openings due to increased pressure values during winter operation.
Intake through the grill and fender.

The AVF (presumably referring to a valve or fitting) only had one opening, and the delta-p values were within acceptable limits.

The two engine variants also have different filters.
In addition, the V6 airbox also has different mounting points.

If you're already modifying things, you should also replace the pipe after the mass airflow sensor (MAF), as this is where the biggest losses occur due to the pipe's undulation.


Best regards, Andi.

matt wrote:

1) Of course, the V6 version would also suck in spray. I don't think that a small hole in the air filter housing would prevent the air filter from being fully saturated. It seems clear that the V6 solution is technically superior. The question now is whether, in my specific case, there is actually too much negative pressure in the air filter housing, making it worthwhile to change the air flow routing. 4) I don't understand your argument about why someone should use a different air filter housing. You can actually make the process yourself. 5) What I could imagine doing is cutting off a small piece from the underside of the trunk to widen that rather narrow slit. 6) However, the use of an open grid is unlikely to be problematic in this case. Because the V6 engine doesn't seem to have any problems with it.

1) Exactly, my air filter was already soaked, and my mass airflow sensor was already broken (though I'm not sure if that was related). But even for approximately 90,000 kilometers, that's not a bad average.
2) Considering your goal of improving performance (or "de-throttling"), then yes. See also 1).
3) For example, if you're driving a vehicle with a higher LD (load displacement), I would definitely consider it. I'm not sure if it would provide any benefit in its stock configuration. It's probably also mentioned in the article.
4) Yes, if you can manage to do it yourself. Replacing the casing will require the least amount of work, and then everything will fit.
5) I didn't connect it to the intake manifold, but rather to the second option, where the V6 engine draws air (at the bottom of the housing, near the fender). If that's not enough for you, I will open the gate.
6) 1)

@ Martin,

Okay, so I disassembled mine this weekend... it has plastic underneath the upper part of the headlight housing, all the way to the left headlight. It also has holes specifically placed next to the headlight on the front panel. However, it's not a 100% airtight connection.

Oops.

I thought it was sucking air from the left fender. At least, so far, I haven't seen anything on the G4 or Leon that I would consider a significant improvement.

However, the Leon was an ASV (which is a VP37).

Perhaps they have changed that with the more powerful PDs.

m;