TheSamba.com :: View topic - Webber progressive 2 barrel, why the bad rap..?

Fri Aug 05, 2011 8:40 am

I've had both dual carbs, and a progressive 2 barrel on my motor, and personally I like the 2 barrel more.. So why is there such a bad rap on webber progressives? Basically all I've heard on thesamba is to ditch the webber, and I'm just wondering why?

Fri Aug 05, 2011 11:40 am

people says that the 2 barrel weber is hard to tune up for the acvw.

I had a twin solex 32/ 34 from a 1302 s and now I have a weber TLDE 32/34 in my T1 1600 stock. Great carb and no problems.
The twin carbs are the ideal set up for the T1. A great article from aircooled.net:

http://www.aircooled.net/gnrlsite/resource/articles/carbs101.htm

Fri Aug 05, 2011 11:55 am

They can be a little tricky to tune and jet properly, that's all. Plus, they really work better with manifold pre-heat which many people don't have any more. There is nothing "wrong" with them, they just require a little more work to get right and most people don't want to do a little more work. :wink:

Fri Aug 05, 2011 3:40 pm

Paul Windisch wrote: They can be a little tricky to tune and jet properly, that's all. Plus, they really work better with manifold pre-heat which many people don't have any more. There is nothing "wrong" with them, they just require a little more work to get right and most people don't want to do a little more work. :wink:
Now thats weird, because I've had nothing but problems with duals, and I'm so fed up with them! So I'm trying the 2 barrel webber to see if its better for me!

Sat Aug 06, 2011 5:47 am

The duals are easier to tune because they are the same size. The progressive carburetor is like trying to tune two different size carburetors on the same engine at different times. :shock:

It's not impossible, it just takes more thought. I ran a progressive on mine for awhile, I just like the duals better for me. The progressive is a good carburetor, it just needs to be set up properly.

Sat Aug 06, 2011 7:21 am

May be some change in manufacturing or setup in the newer ones, but back in the mid 80s, I ran a Progressive Weber with a 009 Dist and it ran very well right out of the box. It was on a DP 1600.

Fred

Sat Aug 06, 2011 8:58 am

Also running a Weber with a 009. Both came with the car and seem to play well together. I can't make any comparisons however. It runs fine and feels reasonably snappy on the road. When timed right the 009 flat spot is pretty much a non-issue. I wish I had enough experience to know if I'm hooked up or missing out. It's sure fun to drive.

Sat Aug 06, 2011 6:49 pm

Bill Fisher's How to Hott Rod Your Volkswagen back in the 70's did some dyno tunneing on different engine and carb sett up's .
They claimed on the 1600 cc D.P. that the Webber progressive didnt really add any substantial horse power gaine's in addition to this that it was known for not perculateing correctly above the carb and that it was known for not aspirate-ing correctly .
Furthermore they insinuated that the Progg's no matter where Jetted or tunn-ed would runn fatt at an idle and skinny at cruise-ing speed's .
But then they went even further to be unspecific about wich manifold profile was used but that Plenum chamberd manifold's were thought to be a waste of time etc. etc.
This discouraged a lott of Webber experimentation with a lott of People over the year's .
But realize here when your talkin aspiration that there are many , many variable's to engine flow characteristic's .
1835cc as example has thinn walled cylinders and short of 1/4 mileing it shouldnt be used as a High CCR Engine as the cylinders distort and heat up under higher CCR 's .
But keep the compression down to slightly above OEM CCR with stock head's and exhaust you can really flow the engine due to the fact that 1835cc engine's typically have great flow characteristic's .
Bigger valves / head profile / Camm profile / CCR / Bore and stroke / carb's / ehaust are all variable's that play apart in aspiration of carb's and or carb .
In addition to this the progressive carb is considerably more complicated than the dual webbers or stock .
More on next post .
Sean

Sat Aug 06, 2011 7:05 pm

Webber Manifold and larger displacement variable's ?
Basically there are 2 common type's of manifold's the plenum style manifold < Considerd to be junk !
Then the original Webber 2 shot hole manifold .
Plenum chambers are sqaure open throat under the carb typically but I have seen some cut oval going from large under the secondary to smaller oval under the primary .
The one you want is the 2 holer < 2 round holes under the carb seperateing both barrel's .
I have never had much luck with aspirateing a progg on a 1600cc D.P. engine .
In fact I experienced pretty much the same thing Bill Fisher's book claimed back in the 70's early 80's and is still sold today in Bugg shop's etc. even NAPA auto carry's this book .
But 1600cc typically stock OEM stock pea shooter exhaust etc. runn fatt at an idle lean at cruise-ing speed .
But add bore to it 1776cc / 90.5 raise the compression 8.7-1 041 head and a free-er flowing exhaust header and I have had excellent result's aspirate-ing the DFAV webber Progressive .
Im sure that there are many different combo's out there that will properly aspirate these carb's .
But most of them in my own personal experience have been with larger displaced motor's over 1600cc and have there flow characteristic's and profile's improved apaun .
Cause you asked !
Be noted before V.W. I was foolin with the progg's on Pinto's and Fiat's even Toyota's .
There is considerable time spent in the proper jetting of the progressive carb for the proper application .
But you thought this was gonna be easy bolt on application ?? LMAO
Just cause it seem's to work doesnt mean it's workin right .
Improper Jetting has smoked a lott of Engines over the year's etc. ?? LMAO
In other word's probably not for the novice mech .
Sean

Sun Aug 07, 2011 8:27 am

Thanks for the thoughts, but *I didnt think it would be easy, it came with the car. I'm just enjoying my first year of ownership and making use of the systems that are not technically broken or overtly distasteful.

Your info encourages me to begin another quest for more original parts and revert to the stock set up. One of my goals is running stock anyhow. I have reverted several components already but not the carb or dizzy yet. My gas millage is sub-par which seems to follow suit.

Sun Aug 07, 2011 8:33 am

When I installed my progressive, 009 and Monza exhaust, my fuel mileage went out the window and it became a dog down low. I got spanked off the line by a 1966 Bug with a stock 1300. I have learned from my mistakes since then, then being 1996-97 High School Auto Shop. If it runs ok for ya, I won't tell you not to. I will just tell you there are better combinations that are more powerful AND more fuel efficient. :wink: Admittedly, I was one of the people who did not spend much time trying to tune it properly, I stuck it on out of the box and expected a racecar. :oops:

Sun Aug 07, 2011 9:25 am

http://www.thesamba.com/vw/forum/viewtopic.php?t=386388

Sun Aug 07, 2011 6:42 pm

Yeah like I said Progg's are a pain to get right but they do offer heat riser tube's and with the right manifold and linkage they also offer the conveinance of a stock throttle cable that need's no altering or cutting for a aftermarket tipp .
There's a lott of common mistake's made with Progg's and dual carb's in general .
Primarily fuel pump pressure .
When you adjust a carb or carb's you are in fact making adjustment's to the air / fuel mix .
If fuel pump pressure is override-ing the carb inlett valve then you can not control the air / fuel mix .
Adjust on it all day long it wont adjust if carb is flooding over as you can not control the flow of fuel on a flooded carb and or carb's .
Stock fuel pump's put out 5-7 PSI for solex carb's .
Webber's how ever have a maximum fuel pressure of 2-3 PSI .
5-7 PSI is twice what a webber carb can handle so if you use a stock fuel pump this fuel pump pressure has to be reduced .
There's away to do it but ask me ?
Sometime's Im not sure you guy's read my post so ??
Or you can buy a electric fuel pump that is calibrated for 2-3 PSI .
NOTE : Electric pump's come in all kind's of different PSI calibration's so make sure you get the right one .
Then you can add a fuel pump pressure regulator < Cheap Chinneeese crappola in accurate etc.
But you can work with um .
If it's any consolation know that Holley's Chinneeese reg's are no better ?
What dual carb's do you have ?
Cut out hole's in the fender well's are a great addition to dual carb's and make tunne-ing / in car serviceing a cinch .
Sean