Why dual, twin-barrel carbs when one, single-barrel would do?

LOL

I cut me teeth on K-Jet, then moved up to Digifant on my last mk2 GTi... none of this fangled diagnostics either... if it broke, you had to work it out!!

I know you can get sequential FI systems now, so I would go with the assumption that modern cars run it Pretty sure that's how the common rail diesels run!!

 

A webber 34/36 is a "twin barrel" carb. Used as a single carb set up on many engines. A favourite amongst Ford enthusiasts amongst others, they somehow found there way into VW flat fours. But as was asked originally in this thread why two barrels?
Well correctly they are twin choke carbs. One choke acts act at low speed ( determined by throttle position ) to give good economy, and the second choke opens at higher engine speeds, or under acceleration, again controlled by throttle position, to give even more power. This way you don't have all the carb working all the time.
It's interesting to look down the carb with the engine running and see it in action.
A twin choke system is one way of doing it but if you look at designs from Webber, Solex, SU, Zenith-Stromberg they all,use different designs. A good article on carbs for anyone interested is here http://en.wikipedia.org/wiki/Carburetor

 

True, but something like a Dell DRLA is a true twin barrel carb - it's two identical carbs in the same casting, as distinct from a progressive carb that has, as you say, one orifice for tootling around town, and another that opens up when you put your foot down.

My old Manta had a GM Varajet progressive on it. It was awful .

 

All I know is that my single progressive sucks and a pair of dells is well a pair of dells.... Pure poetry in automotion

 

Most 1.8 mk2 drivers were carb'd, so it shows what they thought of SPI. Although SPI was used more extensively on Mk3 polos.

 

I agree that a single progressive on a Flat 4 ( for which they were never intended!) is a pain due to the long manifold pipes which tend to be very cold and causes flat spots. I know. I have one! Not for much longer though. Twin Solex waiting to be fitted as soon as the snow goes away. May, by the look of it.

 

I had one on my 1776 - they get a lot of bad press from people who've had problems with them. However when I bought the carb second hand, the first thing I did was get it stripped down and checked by a weber specialist, and I never had any problems with it once fitted to the van. I agree, the long manifold is a pain, but a) it was VW's original design, so they must have been confident that they had designed enough of a solution into the engine to cope with icing, and b) the trade off with twins is the pain of having to balance them.

I'm just glad I don't have to worry about carbs anymore (now with modern FI )

 

What system are you running??

I'll be moving over to FI on the fish once I can afford too

 

Surely the fish had FI to begin with, you mean you downgraded to ropey old carbs

 

Sorry, you misunderstand. I've gone Subaru.

 

Nope... was twin solexes... The germans weren't as fussy as the yanks

Plus moving up to a 2270cc engine, kinda doesn't work on the factory FI

Ah... scooby.. sacrilege

 

Megasquirt?

 

That's a bit personal, isn't it ?

 

Well it must be a decent enough squirt hes got his mrs up the duff

 

Twins I heard...

 

More efficient then .....

 

...seems that way

 

LOL


Yeah, I'll probably be going megasquirt... I like the idea of building the whole unit from scratch

 

Who makes the best modern FI kit to fit a vw flat 4 then?

 

The only place that I know of that does a kit is vwspeedshop...