What kills mpg: Boost vs downshifting?

[JohnnyBronco]

Exactly! You can use a screwdriver as a crowbar, but a crowbar makes a crappy screwdriver. Just as a Prius makes a crappy off roader, but you can use a Bronco on the road!

Prius makes a crappy on roader unless you grew up in a Yugo (not the road speed but the rides like a tractor with a metal seat)

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[Tricky Dick]

Every MPG thread has the "yOu BoUgHt ThE wRoNg cAr" people.

IMO it's commendable to drive your Bronco as efficiently as possible.

In theory, no boost would be preferable. I'd try both ways, in a variety of situations, watching your instant MPG and see what works best.

 

[BroncoPQ]

My 2000 Ford Ranger 4.0 automatic 4x4 gets, at best, around 17 mpg with 160 hp. I have zero sympathy for your inquiry.
Motors are air pumps, most motors are most efficient at their torque peak and below. When you're making boost, you're using more fuel. If you don't want to use more fuel, keep out of the boost.
Turbo motors hate being lugged and never spun, choose your own adventure.

I don't need your sympathy.....just wonder the differences boost/downshifting

 

[Exomodo]

Prius makes a crappy on roader unless you grew up in a Yugo (not the road speed but the rides like a tractor with a metal seat)

Everyone I've ever known that owned a Prius looked and sounded like they were just biding their time until death claimed them, and driving a Prius was one modality to hasten the day.

 

[AZ_Liberty]

You will get the best milage in the highest gear you can maintain without boost.

My wife's F-150 gets better MPG is Sport mode of all things in moderate city traffic, because it holds the gears longer.

 

[USAGUY]

. My goodness, i think this is a terrific question that I have Intrest in. I’m not sure but I would say boost kills MPG vs downshifting.
. What amazes me is how people go off on tangents. “I have no sympathy”, “you bought the wrong car”, “Prius blah blah blah”, “motors are air pumps”, “on my 2000 Ranger yada yada yada”
. Some people on this site are so helpful & smart. Way smarter than me mechanically and thats great and thank you. But some of you gotta get a life and frankly shut up. You may sound smarter with your mouth closed.

 

[JohnnyBronco]

There are differences between boost types. I had 3 3800 supercharged Pontiacs in a row and could get 30 mpg on long trips. Since the SC is always turning the parasitic losses are fairly fixed. However I achieve about same with my wife's twin turbo BMW X4. Aerodynamics or lack of and mass are at play with the Bronco. Put the same engine in a Focus fwd and double your mpg

 

[Werkedperformance]

Blah blah blah useless post, useless post…

2.3/7speed/4.7s….

I was playing with 5th and no boost vs 6th and boost yesterday while driving about an hour each way…..

If maintaining speed on flat ground at 70-75 ish in 6th it stays out of boost. Add heavy rain, any incline at all or even the slightest increase in speed it sees boost.

Same situations in 5th at higher RPM and I don’t instantly see boost, because we have the Revs to pull a bit before we need turbo.


According ONLY to the dash MPG gauge I was seeing 1-2 MPG increase using 6th….. Vs 5th……. But then you need to downshift for an aggressive maneuvering. But cruising open road at 70-75 with no other considerations 6 does seem to yield more MPG than 5 for the purpose of max road trip refueling distance.

Best intel I can offer as of today.

 

[WuNgUn]

Why such shitty mileage? I have a 2.3L Sasquatch and I'm 11.6L/100
Sounds like you're doing straight off road crawling? Lol

Let it use boost...as rpm's go up, so does internal friction. 2X the rpm, 4X the amount of friction.
At some rpm point, it'll be the most efficient with regards to BMEP, but that's more to do with unboosted motors than boosted, cam timing, exhaust and intake tuning, etc.

The best way to improve mileage is with adjusting the nut between the steering wheel and drivers seat.

 

[WuNgUn]

Blah blah blah useless post, useless post…

2.3/7speed/4.7s….

I was playing with 5th and no boost vs 6th and boost yesterday while driving about an hour each way…..

If maintaining speed on flat ground at 70-75 ish in 6th it stays out of boost. Add heavy rain, any incline at all or even the slightest increase in speed it sees boost.

Same situations in 5th at higher RPM and I don’t instantly see boost, because we have the Revs to pull a bit before we need turbo.


According ONLY to the dash MPG gauge I was seeing 1-2 MPG increase using 6th….. Vs 5th……. But then you need to downshift for an aggressive maneuvering. But cruising open road at 70-75 with no other considerations 6 does seem to yield more MPG than 5 for the purpose of max road trip refueling distance.

Best intel I can offer as of today.

The 2.3 drives like a truck hauling a trailer. And incline or hill and you're into the throttle quite a bit. Watching the eco gauge and it'll move from 6 to 8L/100k on flat ground into the 20+L range with a hill on the highway. Chalk it up to little displacement and a lot of weight

 

[ProdigyJKU]

Blah blah blah useless post, useless post…

2.3/7speed/4.7s….

I was playing with 5th and no boost vs 6th and boost yesterday while driving about an hour each way…..

If maintaining speed on flat ground at 70-75 ish in 6th it stays out of boost. Add heavy rain, any incline at all or even the slightest increase in speed it sees boost.

Same situations in 5th at higher RPM and I don’t instantly see boost, because we have the Revs to pull a bit before we need turbo.


According ONLY to the dash MPG gauge I was seeing 1-2 MPG increase using 6th….. Vs 5th……. But then you need to downshift for an aggressive maneuvering. But cruising open road at 70-75 with no other considerations 6 does seem to yield more MPG than 5 for the purpose of max road trip refueling distance.

Best intel I can offer as of today.

2.3/7sp 4.47 BD with 34s and 2in lift.

Between the lift, larger tires, and only 4.47, the is no discernible difference with mine between 5th and 6th on level highway, according to the instant mpg. About the only time I see 0psi in 6th is whey there in a significant decline on the highway. 5th on the other hand will normally maintain 80 with no boost.

At 65mph 6th might be more efficient for me, but at 80 it needs boost.

My Bronco was only stock for 3 hours, so I can't speak on it's factory economy.

 

[WuNgUn]

2.3/7sp 4.47 BD with 34s and 2in lift.

Between the lift, larger tires, and only 4.47, the is no discernible difference with mine between 5th and 6th on level highway, according to the instant mpg. About the only time I see 0psi in 6th is whey there in a significant decline on the highway. 5th on the other hand will normally maintain 80 with no boost.

At 65mph 6th might be more efficient for me, but at 80 it needs boost.

As with internal engine friction, speed (air friction)goes by the same indisputable law of physics....double your speed, use 4X the energy.

 

[PartyMarty]

Boost vs higher rpm probably shouldn’t matter much, either way the engine has to produce the energy to overcome physics, but it’s a drop in the bucket compared to simply slowing down on the freeways/highways. The best way to increase mpg’s is lowering your speed, say from 80-65 mph. By all means, if you want to go 80, do it, but know that’s what’s killing your mpg’s. I guarantee those who are claiming great hwy mpgs have a lot of low speed (65 mph or less) highway miles.

 

[Daktari]

I just drove 1776 miles down to SoCal and back, most on I5 going 80 and then local stuff around Palm Springs, fast on highways and slower around town, avg mileage is 16.9, Badsquatch 2.7 engine. Not too bad for such a heavy brick. Before that I was around 15.2MpG just doing residential and city driving here, but my daily drive is maybe 4 miles to drop off the kids at school or go to the store etc, so engine gets barely warm. I was just happy to see it increase on the trip, hit 17.3 at one time. All from the computer, gave up on hand calc since some gas stations were out of receipt paper and I don't really care enough to write this down and calculate things or use fuely on my phone.
Would be interesting to have someone else do that drive going 65, but not interesting enough to do it myself, I5 is booooooring, LOL

 

[BOT_ROCKET]

There are a lot of variables that need to be clarified to give a good answer, but generally, boost is worse for fuel economy. The difference isn't as significant as it used to be, and if you're talking about low levels of boost, the difference is pretty negligible. Fuel is good at mitigating detonation, so the air/fuel ratio is usually a little on the rich side of stoic when you're under heavy boost, but if you're just talking about hyway cruising under a little boost at low rpm vs higher rpm under a little vacuum, it's probably a wash. One scenario used more fuel per bang with fewer bangs while the other uses less fuel per bang with more bangs.

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