anyone running a single weber 28/36 dcd

[kustom kriss]

just fitted a single weber dcd 28/36 and was wondering if anybody is running one

what jets etc are you using as tried all the uk forums and nobody can help

[Marc]

A DCD on a VW, really? What are you using for an aircleaner?
Many thousands of folks run the 32/36 DGxV or similar carb from Holley or Motorcraft on VWs, and most aren't happy with the driveability. It's not the carb so much as the location and lack of sufficient intake manifold preheat, by the time you jet them fat enough to eliminate the low-end/midrange stumble on acceleration they're drinking fuel.
I've never seen or heard of anyone using a DCD - those carbs were O.E. on a whole bunch of British/Italian/Swedish/etc. I-4 and V-4 engines so there're many configurations. For starters, venturi size must be known. Then which emulsion tubes, since they play a major part in driveability characteristics. Do you know the marque and displacement of the engine this carb originated on? What's your engine/trans specs, and what sort of driving do you mostly do? Just as a wild approximation you might want to start with jetting similar to a slightly larger waterpumper - say you've a mild 1600, set the carb up as it would be on a 17-1800cc O.E. application.
At least it won't be hard to find the jets, according to my source the same type are used in ADF, DARA, DCD, DCN, DCZ, DFAV, DFEV, DFI, DFM, DFV, DGAV, DGEV, DGV, DHSA, DIC, DICA, DIR, DMSA, ICH, ICT, even the 3-bbl IDA.

Here's the factory specs for a Cortina G.T. MK1 (1500). Note this is a relatively high-revving engine, and the venturii are on the large side for a DCD. Similar jetting with smaller venturii may just be about right for a VW. You may also need a larger primary idle jet for the reason mentioned above.

Venturi ("choke") diameter: 26/27
Auxiliary Venturi diameter: 4.5/4.5
Main Jet: 140/155
Air Correction Jet: 230/180
Emulsion Tube: F 30 / F 30
Slow running/idling petrol jet: 50/70
Slow running air jet: 200/70
Progression holes: 2 x 120 / 1 x 120
Slow running volume control port: 1.5 mm
Air bleed in throttle plate: 1 mm
Needle valve: 1.75 mm
Float Travel: 8.5mm
Starter petrol jet: 100
Starter air passage diameter: 6mm

[kustom kriss]

bought a holley 32/36 combo locally but holley was knackered then came across the dcd cheap so thought what the hell

manifold is different from the norm as its a dcnf/zenith configeration



got the dcd on the other day not messed with jetting yet wondered if it would be the same as the 32/36

heres a vid from my phone

http://s671.photobucket.com/user/klumbe ... 6.mp4.html

oh and the side exit dizzy cap is from a citroen bx to clear the linkage

[Marc]

A progressive on a non-progressive manifold....the huge plenum chamber will help you get away with that, but as a rule plenum chambers aren't desirable for low- and mid-range driveability - Zeniths are about the only exception. Do you at least have the preheat pipes connected and functioning?

Generator pedestal baffle in photo is 90° from correct position.

[kustom kriss]

no pre heat pipes going to use a warm air feed from exhaust and from bottom of barrels

heard that pre heat pipes are crap on aftermarket exhaust as insufficeint vacuum to make air flow through unlike original

gona remove tonight and have a look what venturi and jets in it

[kustom kriss]

Here's the factory specs for a Cortina G.T. MK1 (1500). Note this is a relatively high-revving engine, and the venturii are on the large side for a DCD. Similar jetting with smaller venturii may just be about right for a VW. You may also need a larger primary idle jet fro the reason mentioned above.

Venturi ("choke") diameter: 26/27
Auxiliary Venturi diameter: 4.5/4.5
Main Jet: 140/155
Air Correction Jet: 230/180
Emulsion Tube: F 30 / F 30
Slow running/idling petrol jet: 50/70
Slow running air jet: 200/70
Progression holes: 2 x 120 / 1 x 120
Slow running volume control port: 1.5 mm
Air bleed in throttle plate: 1 mm
Needle valve: 1.75 mm
Float Travel: 8.5mm
Starter petrol jet: 100
Starter air passage diameter: 6mm[/quote]

just been and removed carb and took top off, spec is as above except 23/25 venturis was told it had been run on a vw

[Marc]

...heard that pre heat pipes are crap on aftermarket exhaust as insufficeint vacuum to make air flow through unlike original...

Quite true, they're just slightly better than nothing since there's no net flow, the intake is heated more by convection. You may not have too much trouble through the summer in a lightweight car, but come fall you'd better plan on having a pretty good setup to feed warm air to the aircleaner.


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