Vacuum?

It really wasn't a matter of speed so much as throttle position. You have less vacuum with more throttle opening. Going faster generally means more throttle, but the vacuum should stay at a reasonable level as long as you're not pulling a hill or accelerating. I had a five seven chevy once and those wipers are a pain.

the vacuum dropped because the throttle blades in the carb were open further

Proof that silly-assed inventions can make someone a buck

Dave

And then the Engineers came up with a brilliant solution .......a double stack fuel pump that pumped fuel with one diaphram and evacuated air with another diaphram, in conjunction with a vacuum tank! How log would it take before one engineer said " hey, what about electric wipers?"

And if you really go way back, some wipers were only hand operated with a hand crank type lever!

remember that? No.....I wouldn't admit it either....Ha

No heaters or defrosters, only some heat off of a device that surrounded the exhaust manifold and ducted into the inside. Defrosters were a beer can under the back side of the engine hood

personally, I'm glad they don't build cars like they use ta.

Speed really wasn't the issue so much as acceleration. If you floored it the old windshield wipers would just stop. There was plenty of vacuum cruising at high speed.

OK, but what does the carb have to do with vacuum, anyway? I don't understand the connection, yet.

HR.

All of the "vacuum" used in your automobile application is produced by the engine. Different operating conditions effect how much vacuum is produced. Engines with higher performance cam shafts with high lifts and long durations produce much less "engine vacuum" than say an engine with a stock cam shaft. all engines under a load at wide open throttle produce much less vacuum than when running moderately. So any and all accessories running on "engine vacuum" have LESS vacuum during certain engine operating conditions.

I hope this helps...

The engine creates a vacuum as the pistons pull the air/fuel mixture into the combustion chamber from the manifold, which pulls air/fuel from the carburetor. As Gary said, when the carburetor is opened, vacuum is reduced as flow increases.

Hope this makes it a little easier to understand.

Blair

If the engine is trying to pull more air volume than the carburetor can pass, it produces a vacuum in the intake manifold. The more you open the throttle the more volume you can move through the carb / throttle body, which decreases the manifold vacuum.

The "gas pedal" is actually a misnomer, it should be the "air pedal" because that's you're doing, letting more air through. The fuel flow is increased indirectly, from the increased venturi effect of more air flowing through the carb.

Sean

Hook you up a vacum gauge on the inside of your vehicle from your manifold run a hose an put the gauge inside where you can moniter it and you will learn all about vacume.Bobby

On Sat, 16 Aug 2003 23:48:54 -0400, Joe rearranged some electrons to form:

Your statement is only true at part/no throttle. When you floor it, the manifold vacuum goes to nearly zero.

So what part of his statement is not true? I've left it here for your review.

On Mon, 18 Aug 2003 17:10:22 +0000, Steve Barker rearranged some electrons to form:

The way I read it [early] this morning, I thought Joe was implying the wipers stopping wasn't because of the lack of vacuum, or something to that effect. Now that I read it again in the daytime :-( I guess you have a point.

Sorry Joe, I stand corrected.

Acceleration opens the throttle and hence vacuum drops and slows the wipers. My mom had a 56 chevy did the same thing.