More on Vapor CLouds

[Fastjeff57]

You might find this interesting: I have some carbs from a Chrysler 150 hp FIVE cylinder motor. They used THREE carbs: the top and bottom supply two cylinders each, with the center SIMILAR carb supplying that cylinder alone. Main jets in the top and bottom carbs were # 94s, where the center carb had a # 74.

You may recall the discussion we had on gas vapor clouds forming in front of one carb per cylinder motor at certain speeds. The top and bottom carbs on this Chrysler had overlapping suction pulses from the pair of cylinders that kept the vapor cloud in check, but not so that center carb! The airflow made multiple trips before finally getting into the motor, each time picking up a bit more fuel. Hence the need for a significantly leaner jet.

Jeff

[rustnrot]

That's very interesting, FastJeff. I think I can visualize what is going on here with that cloud and how it is formed.

Does anyone know of a pictorial showing it?

[Fastjeff57]

Not me, unfortunately, but I've love to see a photo of it!

On a related (barely) but different subject, you might get a kick out of the Chrysler 70 hp three cylinder's carb arrangement. In this case a vapor cloud would never be possible since all three cylinders breath through a single carb! Note the baffling (contortions!) Chrysler used to get some kind of equal airflow to all three cylinders.

Jeff

PS: The same motor with three carbs was rated at 75 hp! I suspect the single carb version was a bit overrated.