This creates a condition where you have to jet rich to make sure that the airfuel reaching the cylinder is rich enough, because a lot of the metered fuel condensed on the way to the cylinder because its so cold (not vaporized).

The hot intake manifold from the preheat keeps the fuel that is metered at the carburetor (by the idle and main jets) VAPORIZED (Google Latent Heat of Vaporization). If you cant do this, another option is to have the guy at the muffler shop do it, its an easy job for him. Just relocate one to the collector, with some small (38) steel tubing, and weldbraze it in place. It will not work well, please do not ask, because the answer is get dual carbs.īut understand that if you have an aftermarket header with the flanges on 2 and 4 primaries, you must relocate one of them to the collector (like the stock muffler) to get good preheat.ĭont be lazy and think you are special and that these rules dont apply to you. The intake volume is too large, and there is no easy way to get the intake manifold and runners heated up. If the carburetor does not, you got a chinese copy or an old (ie: obsolete) progressive, and you will HAVE no other choice but to run a 009010, but you will NOT have optimal tuning results like you would if you had a SVDA.

Good progressive carburetors HAVE the proper port for the SVDA distributor. They stink Simply run a SVDA (Single Vacuum, Dual Advance), it will make your tuning job much easier. This allows you to jet the carburetor lean for fuel sippin when on the primary, but when the secondary opens you obviously do not care about MPG so it flows a lot more air, since you are probably accelerating or passing. The progressive side does not open until the primary is around 13 open. What that means is the primary throttle plate is 32mm in diameter, and the secondary side is 36mm. We suggest that you get a Genuine Weber Progressive DFAVDFEV Carburetor.īecause our cars are aircooled, we never ever deal with the DFAV.īut if you pull one off of a Pinto or another car in the junkyard, you may have the DFAV version, which has 2 water hoses that run to the choke assembly. Hopefully this article will help some folks, who really have no idea what they are doing, to get their progressive running well. Thank you for your patience while we work diligently to serve your aircooled VW parts needs during this unprecedented situation.

Weber 32 tlf diagram