Is this item part of the venturi system?

Geoman · Geoman's Garage

During the refurbishing of the vacuum lines and air oil separator system, I disassembled the venturi component from the three hoses attached to it and happened to look into one of the hoses. Inside was this small cylinder with a hole through the middle. It wasn't physically attached to the venturi item, but it was just behind one of the ports as shown in the photo.

I can't find any picture or reference to this part. Any ideas what it is? Is it necessary? Perhaps a PO installed it for some reason? Thanks.

v2rocket_aka944 · 09-12-2018, 08:02 PM

it goes in the hose between that Y piece (that IS the venturi) and the intake manifold barb.

it's a little restrictor controlling how much air can flow through there as this is basically a controlled vacuum leak.

Geoman · Geoman's Garage

Ah...thanks for the info. I thought the "venturi" action was due to the restriction within that short port that the metal piece is inline with. The straight tube section of the Y piece has no restrictions, you can easily see through that. But looking into the short angled port, only a very, very small spot of light can be seen when I shine a flashlight through the open end of the straight section (the opening on the right in the pic). So I thought this restriction was the venturi component and the separate metal piece was therefore redundant. Hmmm...I wonder, should the short pipe actually be free flowing? Should the blockage in the short section be removed?

Geoman · Geoman's Garage

Wait a minute, found this image on another thread showing the restrictor coming off the straight portion of the Y pipe. In my photo, the restrictor was found in the tube connected to the angled port. Which is correct? Still want to drill out that blockage in the angled portion of the Y pipe!

v2rocket_aka944 · 09-13-2018, 07:16 AM

Hm, maybe it does go on the other side.
However, the "angled" port goes to the brake booster, the 2nd picture posted above has the venturi facing the wrong way (should be like the 1st picture)

Geoman · Geoman's Garage

Gotcha. You mentioned before that the restrictor...

Quote:

Originally Posted by v2rocket_aka944

it goes in the hose between that Y piece (that IS the venturi) and the intake manifold barb.

Do you mean that it goes "here" (in red) instead? In that case the flow is restricted from both the oil/air separator AND the brake booster....don't know if the booster should be restricted.

v2rocket_aka944 · 09-13-2018, 11:42 AM

it's been a few years but I seem to recall my aluminum restrictor bushing thing being between the Venturi and the intake manifold.

the AOS hose connects to a totally different section of the J-boot - not part of the venturi system at all.

9FF · 09-13-2018, 01:25 PM

I’m just going to take a logical guess that you don’t want the restrictor on any pipe between the intake and the brake booster. So I think where it’s marked “restrictor” on your diagram (not on the photo) is where it belongs.

Btw you can just remove the venturi and restrictor and simply bypass them both without any effect like Porsche did on the later cars.

Geoman · Geoman's Garage

v2Rocket: My mistake, I meant the ICV not the AOS.

9FF: Delete the whole thing...well there's an option! Especially if there's no downside to it. Searching for info on the web leads me to lots of photos with some showing the brake hose going to the angled port and others showing it connected to the straight port. But I agree with you that the brake hose shouldn't have a restriction in it.

Thanks for the input!

9FF · 09-13-2018, 03:58 PM

There’s a comprehensive “Official Venturi Delete Thread” on the dark side.

Geoman · Geoman's Garage

Excellent, I'll check out that link. Just as an FYI for others, the Y connector pulls apart, the black part fits inside the gray part, and there's an o-ring that sits in the groove of the black piece (see pic). If you're redoing the vacuum system, check on the condition of this o-ring.

Now that I realize that the part separates into two components, that explains why I couldn't see light through the short, angled port....the black part extends beyond where that port intersects the straight portion, thus partially blocking out the light.

I would imagine then that the brake booster hose has to attach to the straight (black) section, where there is no restriction.

v2rocket_aka944 · 09-13-2018, 07:54 PM

The booster line definitely goes to the angled leg.

Restriction doesn't matter, nothing "flows" through the line anyways, all it does is provide a constant source of vacuum on the booster diaphragm.

Geoman · Geoman's Garage

Check this video by edradas. Skip to the 4:13 and he shows the setup that I have with the booster going to the straight leg. Perhaps the setup changed with year/model??

Thanks v2rocket for all the help.

https://www.youtube.com/watch?v=58ct-hYbe-4&t=330s

edredas · edredas's Garage

Yes, where the brake booster connects to the venturi is different depending on the year. If you watch my video on the early vacuum lines you'll see its like the diagram you show. I hope that helps!