Boost Guage = Fuel Milage

That's old school "scan gauge". Keep your boost as low as possible to maintain momentum. Driving with your foot and not the cruise to maximize economy. If you're on flat ground and you see boost up at 15-20 psi back out of it a little and see if you can maintain that same speed at 10 psi or lower. Pulling a steep hill of course you can mash the throttle keeping your boost pegged at 45 psi but if you can top the hill using only 20 psi without dropping a gear you'll top it more efficiently. Basically it is driving with an eggshell under your right foot. That boost guage will show if you're cracking the egg instead of feathering it.

 

Basically if you boost gauge is getting up there you are really putting your foot way to hard on the accelerator. If you can manage to keep your boost gauge low you will soon realize better fuel mileage. All the tach really shows you is how many revolutions your engine is doing to maintain the speed you are driving. Your tach could be at 1800 RPMs and your boost at 0 going downhill and you would still be getting great fuel mileage. However if your boost is high you are really burning a lot of fuel. Not sure that makes sense anyplace but my head but that's all I can share. Hope it helped.

 

Rolling said it a little better I think. Lol

 

The more boost you make the more fuel you will use.

 

Yes and no. Boost going up means you're asking for more power. More power requires more fuel. More fuel generally means worse mpg.

But not always. You may get better mpg at 6psi and 1200rpm than you would making the same horsepower at 1600rpm & 4psi.

So horsepower is a better predictor of mpg than boost. In the old days, you didn't have gauges displaying horsepower (scangauge, bully dog, etc) so a simple boost gauge worked wonders. It still works, just not as well as reading horsepower directly...

 

Boost gauge is the opposite of a vacuum gauge in a car. It is indeed an indicator of throttle position. What kind of mileage are you getting? If you are in a cabover, you may not be able to get any better mileage. There's other things you can do to increase mileage. Tire air pressure, air cleaner dirty, trailer skirts or fairings.

 

you must be getting great mpg last 3 weeks

 

Boost is air and the computer strives to maintain the proper air:fuel ratio at all times. Therefore, it's always been my understanding that more boost = more fuel otherwise it would be running too lean.