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> > Has anyone noticed a difference in the vac drilling in late vs early > carbs? > > I checked in my box of carb bodies and they appear to be the same- there is > a .6mm hole in the carb body leading in behind the venturi, then running > down a passage moulded into the venturi into the throttle plate, then out a > square aperture on its base- below the throttle disk. But wouldn't that give > you high vac at idle?- this doesn't seem to be the case- maybe its just at > take off when the throttle opens a little and the engine revs causing a > strong vac beneath the partially open throttle? The early and late all > appear the same though the throttle disk and idle transfer drillings are > different. I guess the vac can might have changed? The way it is done on the FI cars, the drilling is close to the throttle plate in a position where it is upstream when the plate is fully closed and as it starts to open, but when the throttle opens a bit more it is over that port and we get a vacuum there if the air speed is high enough. If we open the throttle all the way the whole aperture is open and the air speed across the port is slowed down and the vacuum drops. It can make a LOT of difference if this port is moved just a few mm so look closely at your parts. OTOH, didn't someone once mention that their port went right into the venturi, which is where I was expecting it for a vac only dist? Is it possible that all your Solex bodies are "late" ones? -- ******************************* Jim Adney, jadney@vwtype3.org Madison, Wisconsin, USA ******************************* ------------------------------------------------------------------- List info at http://www.vwtype3.org/list | mailto:gregm@vwtype3.org