How do Carburettors work?

Carburettors, in very simple terms, are a mixing bowl for a set measure of air and fuel to be blended before entering the combustion chamber to create the power to propel your classic Volkswagen or Porsche.  

Whilst they are simple technology by modern standards, there can be quite a difference between an early VW Beetle carburettor and a VW Golf carburettor, from the use of electronic choke units and multiple vacuum pipes through to the physical size and the size of the fuel jets too.

Best Quality Carburettors for VW and Porsche

We pride ourselves on offering the best quality VW Carburettors and Porsche carburettor parts from all the biggest brands. We work closely with manufacturers such as EMPI, CB Performance, FORST, Weber, Brosol, SSP, Vintage Speed, CSP and Wolfsburg West. Please speak to our team if you have a specific requirement or brand of choice.

Can you repair an old carburettor?

Many restorers are keen to repair their original VW carburettor if they can, which is why we stock a great range of carburettor rebuild kits containing new perishable components such as rubber accelerator diaphragms and replacement carburettor gaskets. Once the carb has been stripped down, it can be thoroughly cleaned out and all jets blown through with a high-pressure airline before reassembly.

If your standard Volkswagen or Porsche carburettor has seen better days, we are able to supply a number of different versions to replace it with. From Solex 28 PICT through to Solex 34 PICT as found on the 1600cc aircooled VW models. We are also able to offer Weber carburettors for both the aircooled VW engine and as direct replacements for the troublesome Pierburg carburettor as found on the VW Golf and Type 25 models.

How are carburettors measured?

Carburettors are measured by the size of their venturi, which is a narrowing tube within the carburettor body that the air must pass through in order to mix with the fuel. These range from 28mm on a 1200cc Beetle carburettor up to 44mm for example on a Weber 44 IDF or 48mm on the Weber 48 IDA. 

The larger the venturi, the more air the carburettor can flow. This will generally equate to more power, provided your fuel pump can deliver sufficient fuel to match it. If not, you will need to use smaller fuel jets or you risk your engine running too lean.

Why do VW Carburettors suffer with vaporization?

One of the downsides to a centrally mounted aircooled VW carburettor is the long intake pipes running to each cylinder head. The VW inlet manifold due to its length, encourages fuel vaporization leading to carburettor icing. Volkswagen tried to remedy this with pre-heat pipes which scavenge heat from the exhaust, but these get blocked with carbon over time reducing their effectiveness. A retrospective add-on called an IMDU can be fitted, which raises the temperatures around the inlet manifold by way of an electric blanket.

Why fit twin carburettors?

Twin Carburettors are fitted for a couple of reasons. With one carburettor per side, the intake pipes become much shorter, drastically reducing the chances of carburettor icing. The other benefit is performance and delivering more fuel and air to the cylinder heads at any given time. There is more space either side of an aircooled VW engine allowing for performance VW carburettors to be fitted, so whether it’s a simple Weber 34ICT upgrade – a great option for a 1641cc engine – or something a little bigger like twin 40’s or twin 44’s for a race car, we have the VW carburettor kits you need.

If you own a US import Type 2 with the fuel injected Type 4 engine, or a Type 25 Waterboxer, you may consider fitting twin carburettors to try and resolve running problems with the original fuel injection system. We can supply Type 4 twin carburettor kits and a variety of VW waterboxer carburettor options too.

Fitting dual carburettors to a classic Porsche

Aircooled Porsche owners can also benefit from our great range of Porsche carburettor kits too. We offer twin carb kits for Porsche 356, Porsche 912 carburettor kits along with a number of dual carburettor kits for Porsche 914.

With a dual carburettor kit fitted you’ll need to install a carburettor linkage kit to ensure both throttles are operated at the same time. We stock a number of these from the best names in the business, such as CSP, Vintage Speed, EMPI and CB Performance. These linkage kits are specific to the type of carb kit and engine type, so shop carefully.