Vacuum Gauge vs. MPG

[turboecho2005]

I am surprised that no one has installed a vacuum gauge to determine the best shift points and driving style for all of your MPG guys!

I have one in my car (well a boost gauge - both vacuum and boost) and you can really notice a difference in gas mileage when driving the car so that you keep your vacuum numbers nice and high. Infact i found coasting in neutral burns more fuel then when the engine is under load. because under load i pull more vacuum psi.

[Reddog99]

It depends on how fast you go when you coast. I regularly see 250 mpg at 50 mph on a Scangage when coasting a downhill grade on my regular route to work. I never see figures that high (except for DFCO) just by backing off the gas (for high vacuum).

Having said that, I have installed a vacuum gage in several vehicles I've had in the past and liked them. I always felt crippled whenever I had to drive a car without the gage, especially a stick shift.

[Sodium Duck]

pix?

[natethegreat38]

I'm doing really well with my Kiwi (and without a vacuum gauge). My last tank of gas yielded 40.2 MPG... not too shabby!

[briman]

Dumb question, but
when does DFCO kick in? I thought it was every time you coasted.

[natethegreat38]

Dumb question, but
when does DFCO kick in? I thought it was every time you coasted.

From what I understand it is anytime you let off of the accelerator above 1100 RPM. Here's a good, easy read:

http://www.yarisworld.com/forums/showthread.php?t=4248

[Sodium Duck]

So I guess we'll never see pics of this vacuum gauge...

[GeneW]

I am surprised that no one has installed a vacuum gauge to determine the best shift points and driving style for all of your MPG guys!

I'm skeptical about vacuum gages on a car that uses computer controlled mixture and both spark and valve timing.

As a rough and ready estimate of efficiency measuring manifold vacuum might be fine but for real in depth work you need to measure gasoline consumed per mile based upon how you drive.

Gene

[natethegreat38]

+1