Product description

The original type 1 engine of our air-cooled VW with a single carburetor is an engine of deliberately simple construction. The engine had to be cheap to produce, reliable and easy to maintain. A major limiting factor of the type 1 engine in terms of power and torque is the single carburetor construction. Ideal for reducing costs and keeping the engine reliable (less maintenance and easier tuning), but at the same time this construction ensures that the engine efficiency isn't very good. With the latest type 3 and type 4 engines, this concept was modified and the efficiency improved, these were equipped with double carburetors or one carburetor per two cylinders.

There have been quite a few alternatives on the market over the years, ranging from single carburetors mounted on the left to a double carburetor mounted in the middle, but by far the most popular and efficient carburetors are the two double carburetors mounted on the side. Actually, you have four carburetors, one for each cylinder. The advantage of dual carburetors over single carburetors is that all cylinders get an equal amount of mixture at the same time. In addition, the mixture flow is only slightly changed in direction, which is of considerable benefit to the filling of the cylinders. These carburetors are therefore particularly suitable for performance engines. A disadvantage is that these carburettrs require more tuning. The best known dual carburetors are the Weber IDF and the Dellorto DRLA.

In recent years there has been a new player on the market, namely the HPMX carburetor. It is marketed by EMPI and sold as a complete package, including manifolds, air filters, rod system and mounting hardware. The set is a cheaper alternative for those who want the advantage of dual carburetors and want to buy something with a good price/quality ratio. In addition, there is the advantage that, apart from perhaps a few other jet sizes, the set is complete. If you prefer to mount a Weber IDF which is also possible, you only have to assemble the set yourself (see replacement parts tab), the sets mentioned here use only EMPI HMPX carburetors.

EMPI is continuously improving the HPMX and the American has done well, independent tests prove time and time again that the effectiveness of the HMPX has surpassed Weber's, i.e. the reproduction is better than the original. The only thing that distinguishes Weber is its proven quality over a very long period of time, and the fact that the cars were then equipped as standard reinforces this. The EMPI has only been on the market for a relatively short time, so long-term reliability testing is not possible, but it looks promising.

A few years ago, Paruzzi was commissioned by EMPI to test the HPMX thoroughly, except for a few details; our tests were also very positive and were not inferior to those of Weber. The results of our tests have been implemented in the HPMX 3.0 which is included in the games.

In the 40 mm version for type 1 engines, two types are available, the standard set and the Ultra set, where the Ultra set is equipped with heavy aluminium air filters and a throttle valve set where the intake manifolds also have a slightly larger offset than in the standard set. The standard units are equipped with metal air filters with the gas bar system and the manifolds adjusted accordingly. The Ultra set is qualitatively stronger but many will buy it for the ultimate look. The Ultra set is only available with 40 mm carburetors whereas the standard set is available with 40 or 44 mm carburetors, depending on the displacement and rpm you wish to obtain. As a general rule, up to 1800 cc, the 40 mm version is sufficient and beyond that, it becomes interesting to choose the 44 mm version.

Note: For type 1 engines it is necessary to adjust the fan shroud to avoid hitting the carburetors, a better option is to order a new fan shroud directly from our shop, these are developed for this purpose.

All sets consist of the following parts :

- 40 or 44 mm HMPX carburetor
- air filters
- intake manifolds
- fuel hose
- seals and mounting hardware
- mounting instructions
- ignition coil change position bracket (only for type 1 sets)
- gas rod system