Turbo newbie question - mpg and boost

[tock13]

This is my first turbo, never wanted one, still don’t but no choice if I want a bronco so thought I’d toss out the ‘dumb question of the day’ post.

I get a Bronco is a brick, I don’t drive fast and furious, and I’d like to do what I can to maximize mileage.

I keep reading to maximize MPG, “keep out of boost”. I get what it means but exactly what boost range fits that comment?

I usually see 0 psi but on winding rolling country roads I see between 3 to 5 PSI coming back up out of the dips and then it’s back to 0 PSI.

Is 5psi dipping into the “keep out of the boost” range or is that range a lot higher?

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[BlueWaffle]

Out of boost means 0 boost.

 

[PWillette]

Dipping in and out at 5psi isn't an MPG killer IMO. Sustained boost say 8psi & above is a different story.

 

[lapazleo]

You'll be fine at those numbers. It' no so much how high the boost number is rather it's how long it's there.

 

[BigBlue7]

Put it in Eco Mode

 

[tock13]

Dipping in and out at 5psi isn't an MPG killer IMO. Sustained boost say 8psi & above is a different story.

It never sits above 0 more than a couple seconds so sounds like it’s ok.

 

[PWillette]

It never sits above 0 more than a couple seconds so sounds like it’s ok.

You're fine. As mentioned above, it's more of how long you are in boost vs. how much.

 

[tock13]

You'll be fine at those numbers. It' no so much how high the boost number is rather it's how long it's there.

I had a buddy who had a Dodge Omni GLH turbo in the early 80s and he routinely got warnings because the turbo shut down. He beat on that thing though but I’m totally paranoid now with a turbo.

I’m an old man in a new suit.

 

[userdude]

If you want to maximize your mileage with your driving habits, use cruise control as much as possible. I use it around town on longer stretches of road as well as always on the highway. Eco I've found doesn't help that much, plus you have to remember to always switch to it.

Additionally, stay below 70mph and preferably 50-60mph, which is where you get the best highway mileage (drive safely). Here in Texas, where we have a lot of country highways, I like to go 5mph under and max out at 65mph if I can to preserve mileage. I've gotten up to 22mpg over 2-300 miles.

The turbo is going to be engaged, you can't prevent that, but smashing on the gas and holding it or going up inclines, etc. is where you'll shovel more fuel for speed.

 

[TrailDust]

Just don't drive into a 30+mph headwind at 80mph with it in 8+psi boost the whole time and you'll be fine lol, think I might have gotten a bit over 10mpg. Welcome to driving in Nebraska.

 

[HPNQ420]

Just don't drive into a 30+mph headwind at 80mph with it in 8+psi boost the whole time and you'll be fine lol, think I might have gotten a bit over 10mpg. Welcome to driving in Nebraska.

If I keep it under 80 with no headwind I get 20, BD 7M. Unfortunately I need to drive the IL Tollway from WI to damn near IN which means 85+. (PSA: If the ISP sees a first digit of “9” in the 70 zone you will get a ticket but 25+ over is where real trouble begins.)

 

[Tricky Mike]

Just don't drive into a 30+mph headwind at 80mph with it in 8+psi boost the whole time and you'll be fine lol, think I might have gotten a bit over 10mpg. Welcome to driving in Nebraska.

I've experienced those same parameters nearly exactly. 0/10, do not recommend.

 

[BlueWaffle]

This might help put it in perspective.. let's see how good I am at explaining things today lol..


Producing a certain amount of HP requires a certain amount of fuel.. no way around it. N/A.. turbo.. blower.. really doesn't matter.. it's mathematical/scientific rule. 300hp from a 250cc motor would need just as much fuel as 300hp from a 632ci bigm block chebby.


Boost, as we know, increases the amount of power a motor makes by forcing it full of more air (and subsequently more fuel) than it could draw in under vacuum.

14.7 PSI from a turbo/blower will double the power output of a motor compared to if it were naturally aspirated. Simple enough. 300hp naturally aspirated motor will make (close enough to) 600hp if one were to put a turbo on it and let er rip at 14.7 psi.


So.... running at 5psi reduces efficiency by about 33%.. around 7mpg in my case.

 

[Baseaf]

Sports mode gives me the best mpg. The higher rpms keep the engine from lugging and it does not get into boost to maintain certain speeds. Low RPMs and higher boost numbers are what kills my mpgs.

 

[tock13]

This might help put it in perspective.. let's see how good I am at explaining things today lol..


Producing a certain amount of HP requires a certain amount of fuel.. no way around it. N/A.. turbo.. blower.. really doesn't matter.. it's mathematical/scientific rule. 300hp from a 250cc motor would need just as much fuel as 300hp from a 632ci bigm block chebby.


Boost, as we know, increases the amount of power a motor makes by forcing it full of more air (and subsequently more fuel) than it could draw in under vacuum.

14.7 PSI from a turbo/blower will double the power output of a motor compared to if it were naturally aspirated. Simple enough. 300hp naturally aspirated motor will make (close enough to) 600hp if one were to put a turbo on it and let er rip at 14.7 psi.


So.... running at 5psi reduces efficiency by about 33%.. around 7mpg in my case.

Good explanation, thank you. so the last paragraph is a good one, I’m only seeing up to 5psi for just split seconds at a time so should be close to getting the best MPG I can get. Last I manually checked mpg it was 20mpg. 4 dr BB SAS 2.3 auto.

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