![]() Put plainly, the emulsion tube plays three very important rolls: 1)It contributes to the "timing" at which the main circuit begins to "come on", 2)It emulsifies, or mixes air into the liquid fuel, and 3)It compensates for the difference in density of fuel and air, as air flow increases (high RPM, say above 5500 RPM). ![]() The reason the above two sections are important, is that the emulsion tube plays a big part in the transition from idle to main circuitry. Secondly, I'll assume you are familiar with the main jet, its circuitry, and the role it plays, when "taking over", as the idle circuitry's contribution diminishes, as the throttle plates open wider. Having said that, I will assume you are familiar with the idle jet, its circuitry, and what part of acceleration it is responsible for. When I began educating myself on emulsion tubes, I had exhausted ALL other tuning practices to achieve a smooth, proper acceleration curve from my carburetors. What you first need to consider, is "why" you would like to change them. There are some basics to consider when looking to change the emulsion tubes. I once found an article about this on a VW web site (below) that was very good even though the examples don't apply to 914's. The placement and size of the holes does tie to mid and high speed performance and engine smoothness. Weber addressed the problem by using the E-tubes to slow the increase in gas flow by bleeding air into the stream. Simply using the increased airflow to draw more gas into the airstream results in rich mixtures. The function of the tubes is to slow the gas delivery by mixing air into the gas flow as engine speed increases. There are surely experts in the club that know about this. I don't know which tubes were used in the larger carbed engines. ![]() Reading I've done indicates that F3, F11 and F26 are the most common E-tubes in 914/6's, at least in the 2 litre cars. Emulsion tube design was a trial and error process and the number means nothing except to identify the tube in the process of experimentation. In other words, what is the functional difference between these emulsion tubes? Sorry for the mini-hijack but I currently have F26's as well and am wondering if switching to F3's might help smooth out the midrange? Mine is a 2.2S-spec and IIRC the 2.0S carbed engines typically used the F3's, but I didn't set up these carbs originally and am unsure if the F26's were deliberately chosen or just "happened".
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |