Vents behind the bumper of a 411?

412s2 · Post by **412s2** » Mon Nov 10, 2008 3:48 am

Hello,

I've asked this question in the Roll Call but I thought it best to start a new topic...

We have a new contributor to the forum, his name is Knut and he comes from Norway. Here is a picture of his newly purchased 411 Variant, a fine looking machine!

Do you notice the vents on the front valance behind where the front bumper should be? I don't have these on my 412 and looking through my collection of 411 pictures I can only find a few with them. Do these vents only come on certain model years or with certain equipment? What are they for? Air-conditioning? Horn grill?

Just curious...

raygreenwood · Post by **raygreenwood** » Mon Nov 10, 2008 4:50 am

Hard to say. I'm betting that car is 1970 or earlier? I have seen probably as many or more 411/412 on this continet and have never seen any with vents there.

In this country the horns were under the bumpers on the outside of the body. They may havge been somewhere else earlier on....remember that we had no 411 here prior to 1971.

As for air conditioning....its funny that you ask that. Behind those areasof teh front valance is where I am installing the AC on mine when it is finished. I had thought about lovers...but they are quite restrictive and I do not like cutting the body. Instead I think I will have two narrow condensors, each at an angle with a thin barely visible scoop peaking out below the edge of the valance. They will be connected by a pressure hose behind the spare tire indention and run in series. That should be more than enough. The fans will be modified muffin radiator fans like those found on mid-90's volvos.

The two most common ways AC was installed was (a) a molded ABS chin housing that ran from side to side under the front bumper with two fans and (b) A specialty unit that sat under the spare tire with a front entrance slot and and a rear exit slot for air.
Both of these systems were dealer installed only. None were installed at the factory. The second method was almost alwasy a butcher job in quality.

I guess the first order of business is to figure out if these slots are afctory in quality or appear to have been done by someone like a dealer. Ray

412s2 · Post by **412s2** » Mon Nov 10, 2008 8:43 am

I've done a little bit more digging on the net and it seems to me that these vents were maybe added for the 1971 model year and then dropped when the 412 was released, at least for models sold in Europe!

Here are some pictures (click on the links):
Without vents...
1969
1970

With vents...
1971
1971 fire engine (look closely!)
1971 2 door
I haven't been able to find a good picture of a '72 411...

It doesn't look as though the vents are for the horn as most cars with vents seem to have their horns mounted as Ray said outside the body, under the bumper; so I still have no idea what they are for!!

That's an interesting idea with the air-conditioning Ray, I wonder if that a ABS chin could also be designed to act like a spoiler and used to prevent front end lift at higher speed. Kamei made spoilers for Beetles in the past (and they are highly prized by the German look crowd) I wonder if they ever made anything for the 411 and 412?

khh48 · Post by **khh48** » Mon Nov 10, 2008 10:29 am

The car is a 72 but the frontplate is from a 70.
When i bought the car i checked the numbers and they didnt match.
the guy who had changed the front had forgotten to change the VIN plate

Lahti411 · Post by **Lahti411** » Mon Nov 10, 2008 10:55 am

I have a '72 411 and it has those vents and no sings of front end repair work. All the quad headlight 411's I've seen, have had those vents.

Lars S · Post by **Lars S** » Mon Nov 10, 2008 12:06 pm

The type4 parts book from August 1970 do not have any vented frontplates as an option (the book usually also covers options), so I guess, if factory made, they were used earliest from about 70.

Lars S

Lars S · Post by **Lars S** » Mon Nov 10, 2008 11:30 pm

When Googling you will find theese wents on -71 and -72 models mostly (bet my -72 Variant had it) and never on -73 -74. The vents look wery factory made, strange it doesent appear in the official litterature.
Since it seems to be common in Europe I would not guess for AC vents but possibly for extra air to brake discs in hilly countries.

It also seems to have appeared in US:

http://images.thesamba.com/vw/gallery/pix/313391.jpg

http://autos.ph.groups.yahoo.com/group/ ... w/e420?b=1

Lars S

Wally · Post by **Wally** » Tue Nov 11, 2008 12:31 pm

Welcome to Knut

khh48 · Post by **khh48** » Tue Nov 11, 2008 11:09 pm

Thanks, Wally

wildthings · Post by **wildthings** » Wed Nov 12, 2008 8:51 am

My '72 411 4dr US model has them. Can't be seen with the bumper in place unless you get down on your knees and peek underneath.

412s2 · Post by **412s2** » Wed Nov 12, 2008 10:04 am

Any more suggestions as to what they might have been added for?

Hidden behind the bumper like they are, I can't imagine much air flowing through them...

Another Type 4 mystery?

Lars S · Post by **Lars S** » Wed Nov 12, 2008 10:51 am

Yes, the bumper acts somewhat like a "restrictor" but still it could be a great overpressure behind it. The gap between the bumper and the body is almost 2" all the way, so there could be a flow of air passing there.
Still it could wery well have been a poor solution but cheap and better than nothing.

-72 was the 1st year of power assisted brakes available, and the last year of these vents, maybe there is a connection.

Until better ideas

(hopefully) comes up I'll stick to the brake ventilation one...

Lars

wildthings · Post by **wildthings** » Wed Nov 12, 2008 11:49 am

I can imagine that they can do much for cooling the brakes, there is no ducting to get the air from the vents to the brake area. The front of the inner fender pretty much restricts any air flow that enters the vents from getting to the brakes.

raygreenwood · Post by **raygreenwood** » Wed Nov 12, 2008 11:55 am

I don't think it had anything to do with the brakes because there is a baffel right behind those louvers of a depth of at least 4" made up of the inner fender wall. Its doubtful air entering the slots could go back and then some 10-12" sideways to the rotors.

BUT...the 411 always had serious air lifting/wandering problems. Partly this was due to the rounded from shape (which in itself causes lift) and party due to the huge area underneath and partly due to that damn nose high attitude when the trunk is empty. Add to this....a shortage of castor.

I think this...because now that you mention that the 72 was the last year of the louvers (which I have never seen)...it was also the last year of the 411.
The shape of teh 412 was not just a marketing issue. It had definately improved wind handling characteristics...and was also built with 5 degrees more static castor built into the steering knuckles and the control arms.

I wondering if the slots weren't an attempt at holding the front end down. There is an air trap right behind each set of slots....a deep one at that.....which is precisely why they will be perfect for locating a small condensor in each side. Ray

Lars S · Post by **Lars S** » Wed Nov 12, 2008 12:11 pm

Ray thats a good idea! Yes, the 411 nose needs some "calming down", the vents could have helped to some degree. It does not explain why some cars have it and others not, but still it's a good suggestion.

More suggestions?

Lars