Carb / intake recommends

[MK6/GLI]

I'm looking for info on a good carb set up.
I'm building a duel port 1968cc 74 crank and engl 100.
Currently the carb is a solex pict 3 34.
I want to keep the single carb type set up.
What would be a good 2 barrel carb? I like the way the idf set up looks.
Any info would be appreciated.

[oprn]

First off, the vast majority of guys here will try to talk you out of a single center mounted carb with the reason being that "dual carbs are easy to set up and tune" and "dual carbs get better fuel economy".

On the first one (dual carbs are easy to set up and tune), you will notice there are multiple threads and many pages of dialog on setting up and tuning dual carbs. The upside to that is that there is volumes of good help to get them working well but... is that an indication of them being "easy to set up"? Or is it just a "this is what everybody does" thing... you decide. There is absolutely no doubt that one carb barrel/cylinder makes the most top RPM HP.

The second argument for dual carbs (dual carbs get better fuel economy) may not actually be totally true. From personal experience, I would modify that statement to "dual carbs get better fuel economy than a poorly adjusted, poorly tuned, worn out, poor quality center mounted carb on a plugged 50 year old intake manifold with insufficient heat and a mismatched distributor. The vast majority of air cooled VW engines today are found in this state when the owner changes it to dual carbs and this I think is where this belief comes from and it is true! Personally, I have yet to get my dual Weber IDFs to match the fuel economy that I am accustomed to from the well-tuned, parts matching stock VWs that I have owned in the past. Better power? Run smooth and sweet? Look good? Absolutely! Fuel economy? Not so much.

The only center mounted carbs I have experience with are the stock ones. Ok, not totally true, I tried a Holley Bug Spray once... that was a complete disaster! John @ Aircooled.net has spent a lot of time tuning and making the Weber progressive work. He has lots of good information on his site that is worth a read through. A number of guys on this site have had good results with Weber and Dellorto 2 barrel center mounted carbs so do a search and see what they have come up with.

A few others are playing with the stock Solex carb, removing the venturi and/or boring the body out to 36mm.

It seems that no matter what center mounted carb you use the formula to success is always lots of HEAT! The long horizontal runners of the intake manifold dictates that and success is totally dependent on it. I know that is totally the case with the stock Solex carbs! Note: Very few exhaust systems available today supply enough flow for the intake heat riser to work properly. Keep that in mind.

Good luck and keep us posted!
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We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)

[MK6/GLI]

Thank you!
I'll check out that website also.

[Cusser]

I've run a single Weber 40DCNF on my 1835cc dual port engine since back in 1976. The carburetor has NEVER been off its manifold, but I did replace a leaky accelerator pump once.

But you'll need to deal with what is available these days, just wanted to relate that I've been satisfied with a single aftermarket carburetor.
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1970 VW (owned since 1972) and 1971 VW Convertible (owned since 1976), second owner of each. The '71 now has the 1835 engine, swapped from the '70. Second owner of each. 1988 Mazda B2200 truck, 1998 Frontier, 2014 Yukon, 2004 Frontier King Cab. All manual transmission except for the Yukon. http://www.thesamba.com/vw/forum/album_page.php?pic_id=335294 http://www.thesamba.com/vw/forum/album_page.php?pic_id=335297

[Alstrup]

[chrisflstf]

I havent done this, but always wanted to try a 40mm sidedraft weber on a bus. But the intake would have to be custom

[oprn]

[MK6/GLI]

When I watch videos about carbs and what literature I can get through. It says that carb is not enough. I have come across one set of videos modifying the 34 and having it work out good on his bug. I read it's best for one to one with the carbs. But I really do not want to mess with duels. I don't think where I drive this thing would work out well. Lots of gravel roads out into the owyhee mountains. So the single idf is starting to look like a good way to go. And if I'm understanding the how duels give you the best all the way around. But I honestly do not know. This is the first time messing with air cooled tech. [/code]

[APPLEGREENVW]

[Multi69s]

[Alstrup]

[BFB]

Nice to see so many ppl offering good responses and info without cramming duals downs the guys throat.
Ive built a lot of single center mount carbed engines with a majority being progressive 32/36’s and really like the set up for all around use. Now these have been on dune buggy’s and most dont get driven in the winter and the ones that have there’s been several occasions where the carbs and intakes have iced up and a few froze.. but for the weather you’d normally drive a dune buggy in Ive noticed no difference whether i run manifold heat or not. The progressives run good IF you learn how they work and tune it correctly and get better fuel mileage and seem to me to have a better bottom end and street drivability. The 38/38’s I’ve had more troubles out of than i think they are worth though. The single Weber or dellorto style would be a step up in performance and top end but lose a little streetabilty ( compared to the progressive ) and can have a that dead spot right off or if you floor it but that also depends on the engine, timing, etc.
I think anything would be better than a stock single barrel but i also just generally dont like those carbs and can’t tune one to save my soul.
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Forced induction can overcome a lot of obsticles that gets in it's way
"You are the Engineer and the Mechanic.  
Build it your way not the way someone else does it. Their way might not work for you." - clonebug
An interesting thing happens in forums where everyone starts parroting the same thing and "common knowledge" takes over.
“ The monkey see monkey do mentality seems to run deep in VW people. "Gene Berg said it was so 30 years ago so thats the way it is" “ - bdkw1

[Alstrup]

BFB.
I agree with you most of the way. I also have no problem with progressives, - and don�t care for the 38/38 DGAS either. The largest issue is that today a proper progressive manifold included will set you back at least the amount that a cheap set of duals will. Then it is not so difficult to understand why and what people chose.
However, it does continue to surprise me that people have so many issues with the 34 Solex. I mean, it IS pretty simple. But of course, if the first step is to slap on a centrifugal distributor then I kinda understand peoples problems. But that is self enflicted and not the fault of the carburettor.
Stock or slightly modified stock carbed set ups easily support up to about 85 hp, dependant on combo of course. Still with proper idle and low speed capabilities. From thereon up you need to know what youre doing.
If you are an engine assembler type of person without the options for doing some machining and or modifying yourself, you can today buy your way to a complete stock style intake system with a modified Solex that will support 140 hp in a good set up.
Right now there is a "gap" of a decent off the shelf parts in the performance window between approx 88 to 115ish hp. But we are working on that. With a little luck these parts will be available before next spring.
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[AlteWagen]

[Alstrup]

The centermount Kadron idea was actually solid. As a matter of fact the 40 Solex EIS was originally designed for a 2,2ish liter Brazilian off road vehicle. I worked with the idea too on recommendation from Joel Mohr since he worked with it for a while.
There is no doubt that if you build the manifold right there is a lot of power potential in it.
IMHO what killed the idea was the fact that especially the Empi produced kit had so many little bits and bobs that made the linkage overcomplicated and would relatively soon make for a sloppy linkage. 2nd, It had to be a carb with cold start enrichment or the first 5-7 minutes after a cold start was left the car virtually undriveable unless you were in +25C enviroment. The Mohr design which I used was better, but it also had its flaws. So I abandonned the project.

It was also at this time some German tuners began to do the 37 mm mod. I�m not sure, but I think RMB and Jens Fild were the first to do it. (Somebody correct me if I�m wrong) I learned my babysteps from RMB, and then it took off to where it is today. We are still not done learning, but we have come a long way since then.
Today, with the 39 Solex and also the Wensing "sports 39" Solex and Wensing manifolds etc it is pretty easy to build a 140 hp sgl carbed 2234 to 2275 engine. You can of course do it on less displacement too, but if you want a stock like idle you need the displacement versus cam timing to be right. If you can and will accept idle like an overcammed V8 you can do it with less displacement.

My/our main customer segment is the bus people. Some are just tired of the dual carb noise in a family camper, some don�t want the maintenance, or can�t do the maintenance themselves, so they want a simple turn the key and go solution.
One of my succes stories was an elderly gentleman who is travelling the Europeian continent with his wife in a �69 beetle with a MKP camper behind it. He wanted some more pulling power in the lower rpms to pull the camper with more ease. He got a 1914 engine built in another shop with the classical W110 cam, (on top of that his specs sheet said W100) out of the box large valve heads, new dual Chinese 40 IDF�s, Chinese 009 distributor, his own stock heaterboxes and 1�" Super comp exhaust. I got to try and dial it in. It pulled a "whopping" 111 hp and 159 Nm torque, - but not much power where he needed it. Needless to say the guy was far from satisfied. He asked me what could he do to make it the way he wanted it. I told him "Take it apart and build it properly, eventhough it will cost you" 3 days later the engine sat on a pallet outside my shop. I sold the carb kit, heads, cam/lifters and the 12� lbs flywheel. Took a refurbished stock flywheel, and rebalanced, made a set of 37,5 x 32 valved heads out of AA500 bases, got a new cam made for it which is kinda like the CB 2232, with a twist. 8,5 CR, Machined the case for zero deck and made the deck height in the heads, Modified CB centercection and modified stock end castings, 37 mm Solex. Now the engine only pulls 104 hp, but it pulls 169 Nm torque and does the whole thing 6-700 rpm earlier. Now the engine will pull the camper at 1700 rpms in high gear and pick up with ease. The customer also stated that the cabin noise was reduced by 50% and his fuel economy when pulling the camper has improved from 12 l/100 to 10l/100.
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https://www.thesamba.com/vw/forum/viewtopic.php?t=435993

[AlteWagen]

[Alstrup]

Carb is turned, so there are less moving parts in the linkage. Also, Carb was raised about 3/4"
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[mikedjames]

A well warmed progressive Weber 32/36 with a stock air cleaner and hot air feed, custom air feed box over carburettor, and heat risers works well on my 1641 bus - I only rev it to about 4500 rpm. I modified the linkage so the throttle lever pulls horizontally ..

Intake air temperature at 85F thanks to VW OG thermostat/vacuum flap system.
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Ancient vehicles and vessels

1974 VW T2 : Devon Eurovette camper with 1641 DP T1 engine, Progressive carb, full flow oil cooler, EDIS crank timed ignition.
Engine 1: 40k miles (rocker shaft clip fell off), Engine 2: 30k miles (rebuild, dropped valve). Engine 3: a JK Preservation Parts "new" engine, aluminium case: 26k miles: new top end.
Gearbox rebuild 2021 by Bears.

1979 Westerly GK24 24 foot racer/cruiser yacht Forethought of Gosport.
1973 wooden Pacer sailing dinghy

[mykidsbug]

MK6, any updates? I’m switching mine to Dual. My new mechanic is 182 years old, I want to switch to dual carburetor’s before he gets older. Plus, with my single carburetor, my old mechanic said I have to off set rear deck. Moisture and rain can get inside my engine.

[MK6/GLI]

I'm going to run duel 39 pict 3 big bore carbs. I just swapped my 34 for the 39. It seems to be working fine.