gas mileage question

[yeti]

trying to understand of how i am going to get the best gas mileage out of my car

so if the boost gauge reads vac. 20 at no throttle is that using more gas than having the turbo build up to make about 3pounds o boost making the turbo spool up a little bit just to help out with gas mileage.
or should i try to go with a medium and try to raise throttle to zero boost?

or is any boost losing gas?

 

[fuel]

basically the more vacuum or least boost your engine sees, the less fuel it will use. Using the boost gauge you can see it's sometimes more economical to go up a hill in 4th gear with less throttle even though the engine is revving higher than 5th gear with more boost/less vacuum.

 

[Barnes]

The only way you can help your gas mileage is to drive slower, or accelerate up to the speed limit slower. Changing your boost pressure higher or lower will not really make a difference. Once you are cruising at your speed of choice, the only way to increase MPG is to have the car tuned using some form of aftermarket tuning to run a leaner burn. Also, make sure your tires are properly inflated, and your windows are rolled up. That's about it. /ubbthreads/images/graemlins/dunno.gif

 

[2of9]

stay off boost, stay in vacuum. I've gotten 25-27 mpg on long drives and it's amazing and still shocks me till this day. Put cruise control on, 60-62 mph on a trip up north without seeing the gas station was quite amusing /ubbthreads/images/graemlins/laugh.gif. I've learned that just staying off boost, not having a heavy foot, not accelerating hard or speeding can definitely save you some mpg's here and there.

 

[Brunoboy]

yea ive gotten over 300 to a tank once, but never again.

 

Is your EGR installed and working? That will affect your mileage.

 

[yeti]

egr?

 

[Brunoboy]

Smog stuff... I dont have any smog parts on mine anymore

 

[yeti]

ya probly no smog stuff i dont have a cat

 

[Barnes]

EGR = Exhaust Gas Recirculation. It is a valve attached to the #4 intake runner on your intake manifold. Has two little vacuum ports sticking out of it. It recycles exhaust gas back into the combustion chamber to reduce unburned hydrocarbons from being released into the atmosphere.

 

[Brunoboy]

Check thermostat as well and coolant temp sensor, if it thinks its running cold your gas mileage will be sh!tty

 

[Wizardawd]

Egr will have little effect on mileage. Tire inflation, easy driving, aerodynamics (wing, etc), state of tune are key. New plugs have a big effect.

My 1g awd gets 29 or so highway and 25 in town.

Wiz

 

[LUNARFX]

These are great recommendations so far. I used to joke that I would get the best gas mileage if I don't hear the blow-off valve go off in between shifts. Getting a bigger turbocharger will take care of that anyhow. I can personally attest to having excellent gas mileage (+400 miles everytime on a tank of gas in a DSM at 350whp), by a great tune (JESTR Tuning), always having my tires inflated 10psi below maximum recommendation, using cruise control A LOT, proper maintenance (oil, filter, sparkplugs) and if it makes a difference letting off the gas pedal when I'm within a few hundred feet as the light turns yellow. It's amazing how much improvement in gas you achieve from 25psi, to 40psi in your tires.