So, I got a lot of info about driving with the tach for a speedo.

Anybody ever drive with a vacuum gauge hooked up? I was reading it was something the old guys used to figure how to get better mileage.

Any ideas?

 

Do a "search" using topics like vacuum gauge tune up. You will gain a lot of good and interesting information. One wants to drive where the vacuum is the highest to obtain the best fuel economy.

Welcome back from your honeymoon!

 

It's a very simple concept; The more the throttle is closed while the engine is running, the higher the vacuum reading. Keep the throttle closed as much as possible, and you will get better fuel mileage.

 

So a vacuum gauge is a stupid idea then? Just use your noggin and don't be a lead foot...

 

Vacuum Gauge = Analog Throttle Position Sensor for your ECU (brain)

It's a good visual indicator of throttle postion without having to watch your foot (bad idea), is also a works as an analog M.I.L or C.E.L...

 

Just 1 to 3 inches vacuum change does make a diffrence in MPG. That's something you will not feel but able to see with the vac guage. I have them in my 89 F250 and my vacuumless(no wonder why a 460 gives crap mpg) 95 E350. Now on my E350 when BOTH AC compressers are running the vac will drop 2" but I don't feel anything loading the engine.

 

If you have a carb with a power valve, a vacuum gauge could be handy to have for MPG purposes. It's simple: the more throttle, the less manifold vacuum. This is where it pays to know which power valve is installed and it's opening point. For example, if you have a 6.5 power valve and the manifold vacuum drops below that figure, the PV will open up and allow more fuel to be used. Keep it above the opening point and you will burn less fuel.

 

If easy to hook up, I think it would be nice to be able to see the vacuum all the time. Aside from mpg considerations, it would be a nice "tuning monitor" - when you are at idle you can see that it is steady at 18 mm Hg or so, and if it isn't steady that would indicate something may be wrong.

 

I have truck driver friends that drive using the vacuum gauge as a guide line. They claim it does save them fuel.