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Thu Aug 26, 2021 3:34 pm

Sometimes people offer odd VW stuff to me. In this case it is a new in box single Weber 24/24 progressive single carb and manifold for a 1500 single port engine. The center section is unique because the 2 barrels feed into the top part like normal and then part way down split into 2 individual runners. The center is case aluminum while the single port end pieces are steel. It doesn't use VW boots between the center and ends but strait hose sections and comes with 8 hose clamps (2 for each end of each connector, I guess.)

It looks quite a bit smaller bore than the common Weber progressive. It has a mechanical secondary and a manual choke. Are regular Weber progressive parts used inside this thing? Would it be a good carb setup for a near stock 1600 single port engine?

Thu Aug 26, 2021 5:27 pm

Its a Weber which is originally made for the Brazilian market. Not sure if they had a licenced production of it. Most likely.
On a 1600, - dont bother. Unless you want to use it to dare to be different. When both barrels are open it barely equals a regular 34 Pict3. But If you invest some time in dialing it in I´m sure you could make it do very good fuel efficiency. If you had a 1200 cc engine there could be some idea in it.

Thu Aug 26, 2021 8:36 pm

Thi sounds strangely similar to the carb they had on the VW dasher for the 1.5L.

With the air cleaner off it "looks" at a glance like a single barrel. Look down the throat and its two equal sized barrels that were progressive.

Ray

Fri Aug 27, 2021 6:12 am

My '76 Rabbit came with a Solex/Zenith 2 barrel progressive carb. By the time I got it to work properly the throttle shaft bores were worn enough to cause erratic idle. I still have it and have wondered how it would have worked on an air cooled 1600.

Fri Aug 27, 2021 9:47 am

It could be a good carb for a stock or very mild 1600 Dp

I don't think it would be good for a SP, but the larger manifold ends (if they are larger) are good for a SP

Fri Aug 27, 2021 12:39 pm

oprn wrote: My '76 Rabbit came with a Solex/Zenith 2 barrel progressive carb. By the time I got it to work properly the throttle shaft bores were worn enough to cause erratic idle. I still have it and have wondered how it would have worked on an air cooled 1600.

That had to be be same carb. They were overly complex for a small two barrel.....well...at least compared to something like a Holly 5200 series.

They were a pain to get running right on the few I worked on.....and thats because they all had the moderate to high miles problem you describe.....worn out throttle shaft bores causing idle issues. It took me a while to figure out the same thing working on a few Dashers and Foxes......because I am less carb centric than injection centric.

For some strange reason I keep getting the recollection that this was not a progressive carb per-se....that the two eqyal diameter throats were geared together and opened at the same time. Ray

Fri Aug 27, 2021 2:05 pm

It is a mechanical progressive carb with the typical pin on a bracket attached to the primary throttle shaft running in a slot in a bracket on the secondary throttle shaft. Early movement of the primary doesn't move the secondary throttle but that setup doesn't look very efficient. I didn't play with the throttle except to see it moves freely, but I think the secondary starts to open slowly then quickly as the linkage moves farther.

Alstrup has a very good point. 2 barrels that are 24mm each add up to about the same area as 1 barrel that is 34mm. Since a 2 into 1 increases the plenum space it is perhaps not a great plan for a stock cam engine, and way to small for much else. It was interesting to look at. If it had 40 horse end pieces I might have bought it and tried to find it a big bore 40 horse home.

Fri Aug 27, 2021 2:34 pm

EVfun wrote: It is a mechanical progressive carb with the typical pin on a bracket attached to the primary throttle shaft running in a slot in a bracket on the secondary throttle shaft. Early movement of the primary doesn't move the secondary throttle but that setup doesn't look very efficient. I didn't play with the throttle except to see it moves freely, but I think the secondary starts to open slowly then quickly as the linkage moves farther.

Alstrup has a very good point. 2 barrels that are 24mm each add up to about the same area as 1 barrel that is 34mm. Since a 2 into 1 increases the plenum space it is perhaps not a great plan for a stock cam engine, and way to small for much else. It was interesting to look at. If it had 40 horse end pieces I might have bought it and tried to find it a big bore 40 horse home.

So its a normal sequential progressive. I must be thinking of a different carb or even an efi TB that moved both plates at once.

But.....one thing about having two smaller throttle plates to equal to one larger one in total area......on engines that they are sized properly for....they work very well. The problem with having a single large plate for some smaller STREET engines....is that the larger plate loses contollability in the mid part throttle range because the pedal stroke length does not match the rotation . It acts the same as having a TB that is grossly too big.

I remember that on the little 1500s of the Dashers and Foxes....these carbs were very smooth. Ray

Fri Aug 27, 2021 4:32 pm

I suspect.... the venturis are 24mm, the throttles are 32mm

Fri Aug 27, 2021 4:33 pm

It is a bit of a complicated little beast. The secondary seems to be vacuum operated with a mechanical lock out from the primary it looks like. Ya, been many years since I looked at this thing...

Throttle plates measure out to be 32mm. I am with Modoc on this that it would not benefit a single port engine much if any but might work alright on a dual port. It would be a challenge to fit as is though with all it's warts and gizmos. Pretty bulky.

When I went turbo I pulled it, went to a '75 Sirocco intake because it had a Solex PICT 34 so had a simple single hole instead of the plenum for the progressive. Then I went Weber 40 DCOE draw through.

This carb hasn't seen service since then.

Fri Aug 27, 2021 6:02 pm

oprn wrote: It is a bit of a complicated little beast. The secondary seems to be vacuum operated with a mechanical lock out from the primary it looks like. Ya, been many years since I looked at this thing...
[snip]

That is not the carb I saw in the kit. I found an example of the carb I saw for sale here.

The throttle plates looks so small against the base, and at a glance I would say the base is the same as the common Weber progressive carb kits available now. I didn't measure anything, I looked over the kit and told the guy I would look into it.

I get shown this stuff because I won't rip people off. I will tell them what is seems to be worth, what is actually worth to me, and be strait with them. It doesn't look like this is for me. It doesn't seem to have much value, perhaps more if it was the same kit except with 40 horse end pieces. It is a vintage speed thing, but perhaps one forgotten because it didn't live up to expectations. I kinda think the owner feels it's too many dollars of great vintage. Interesting and desirable can be different things. :lol:

Fri Aug 27, 2021 6:30 pm

Near zero supply, near zero demand.

So it's priceless

Fri Aug 27, 2021 6:44 pm

modok wrote: Near zero supply, near zero demand.

So it's priceless
Perfect. I like it.

Max

Fri Aug 27, 2021 7:53 pm

I suppose if someone's life ambition was to collect an example of every carb Weber ever produced and put it on display...

I don't know of anyone doing that though.

Fri Aug 27, 2021 9:24 pm

IMO they should be equally valuable as what people here call a "normal progressive"
so, around 20$ :P

There is also model with the float bowl located around the primary barrel instead of off to the side, THAT would actually be the correct one to use on the flat four.
(the float bowl is supposed to be forward)

collect the whole set!

Sat Aug 28, 2021 4:40 am

I started collecting an example of every "produced for general sale" 4 cycle model airplane engine 0.30 cu in and smaller, even the ones that were failures. None of these little engines are in production anymore and you would be surprised at what some people want for the ones that were duds!

Just missing one now and I will not pay what is being asked for that particular dud! To me they are worth $40 if new in box or $20 if they have run but guys think they are worth new price because they are out of production! You only got 3 or 4 runs out of them before the valves leaked.

Sat Aug 28, 2021 6:42 am

oprn wrote: It is a bit of a complicated little beast. The secondary seems to be vacuum operated with a mechanical lock out from the primary it looks like. Ya, been many years since I looked at this thing...

Throttle plates measure out to be 32mm. I am with Modoc on this that it would not benefit a single port engine much if any but might work alright on a dual port. It would be a challenge to fit as is though with all it's warts and gizmos. Pretty bulky.

When I went turbo I pulled it, went to a '75 Sirocco intake because it had a Solex PICT 34 so had a simple single hole instead of the plenum for the progressive. Then I went Weber 40 DCOE draw through.

This carb hasn't seen service since then.
These carbs are not my strong side. But if I am not mistaken this one is out of the E2 A series. Totally different carb.

Sun Jun 08, 2025 6:35 pm

i have a dual setup of these brazilians ony my 71' (from denmark) they dont run very well and im a beginner so its abit of a tough spot for me hahaha

Mon Jun 09, 2025 6:45 am

ive seen those 24/24's on several dual carb set ups.
I'm pretty sure I have one of those set ups in my parts 'pile', too. picked it up just for the vintage nostalgia .... I figure I'll try it on something one of these days. i also dont think the just because something isn't in use nowadays doesn't mean it didnt work, it could be that, but its more than likely predominately based on product marketing