Optimal Cruising Speed for MPG

[DanielMena9]

Hi all, I am running the Turbo and was wondering if anyone ventured in finding the optimal speed on the highway for maximal mpg (things like temp, air density, etc vary but generally should be around the same speed)?

If not, what would be the best way to determine this scientifically?

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[Gavnzdad]

You'll never get a straight answer on this. The mpg variance has been (+/-) 5-10 miles per gallon.

 

[DanielMena9]

You'll never get a straight answer on this. The mpg variance has been (+/-) 5-10 miles per gallon.

But it might be the case that at 70mph you get your highest of 50mpg and @ 70mph I get 40mpg, while our mpg is different our optimal might be the same or close to the same. Especially since the drag coefficient is the same among the same body type.

 

[inv4zn]

I believe rule of thumb is ~55mph +/- 5mph.

If you really want to test it out, use cruise control and the instantaneous MPG gauge in the cluster to find optimal speed.

If it's worth anything, here's something from the gov't, although it's just a poor excel spreadsheet with no data to prove it.
http://fueleconomy.gov/feg/driveHabits.jsp

 

[Blues]

I've been testing this myself. I have found that the optimal cruising speed for MPG in my Civic 1.5 is between 45-55 mph.

 

[tacthecat]

Hi all, I am running the Turbo and was wondering if anyone ventured in finding the optimal speed on the highway for maximal mpg (things like temp, air density, etc vary but generally should be around the same speed)?

If not, what would be the best way to determine this scientifically?

Scientifically, duh - empirically, just use same stretch of road, little of no traffic, reset one trip meter and cruise at a fixed speed for 10 or 15 miles and record the reading (yes it's all relative, not absolute).
Historically between 45 & 55 is the most efficient - aero, etc.
Repeat in 10 mph increments under similar conditions. You can then do smaller increments around the 3 best consecutive numbers.
Our '12 Si gets the best at 62mph 38.75 mpg ave for 2900 mile trip, at 70mph we average 34.6 mpg for 300+ miles. These are real world numbers and of course include hiway speed variances plus a limited amount of stop & go.

 

[Billy4202]

I've been testing this myself. I have found that the optimal cruising speed for MPG in my Civic 1.5 is between 45-55 mph.

Agreed, this is the optimal sweet spot. On relatively flat roads (few roads are flat here), I can get 55-60 MPG on some trips.

In terms of "real" highway driving? I've noticed that if I aim for closer to 80 than 70-75, my MPG on my commute is a little higher. Go figure. All about throttle position with this car, seems really sensitive in that regard.

 

[89AKurt]

From professional mobile road blockers:
109 hypermiling / ecodriving tips ...
Have you tried drafting trucks? ;^)

 

[Billy4202]

From professional mobile road blockers:
109 hypermiling / ecodriving tips ...
Have you tried drafting trucks? ;^)

I draft trucks so hard the Collision Mitigation Braking kicks in #boss

All joking aside, a lot of hardcore hypermiling tricks are just insane.

 

[Gavnzdad]

All joking aside, a lot of hardcore hypermiling tricks are just insane.

Yeah, let's risk certain death, or killing a family of 4, to save a little gas, and get 1 mpg more.

Hey, I'm a poet.

 

[silverrascal]

Is there anywhere where one can even drive around 55 mph on a highway anymore? If I drove 55, I'd get run over, honked at or the one-finger salute.

Agreed, this is the optimal sweet spot. On relatively flat roads (few roads are flat here), I can get 55-60 MPG on some trips.

In terms of "real" highway driving? I've noticed that if I aim for closer to 80 than 70-75, my MPG on my commute is a little higher. Go figure. All about throttle position with this car, seems really sensitive in that regard.

Don't know how you guys can get over 50 mpg. That's amazing. Best I've ever recorded was around 42 mpg.

 

[DanielMena9]

From professional mobile road blockers:
109 hypermiling / ecodriving tips ...
Have you tried drafting trucks? ;^)

Thanks for this link! I'm having loads of fun reading !

Currently averaging 50+ mpg on my 35 mi commute (30 hwy and 5 street). Although all this engine off stuff, probably doesn't work with a Civic

 

[DanielMena9]

Thanks for this link! I'm having loads of fun reading !

Currently averaging 50+ mpg on my one-way 35 mi commute (30 hwy and 5 street). Although all this engine off stuff, probably doesn't work with a Civic

 

[89AKurt]

... Although all this engine off stuff, probably doesn't work with a Civic

Yes, don't recommend even thinking about it.
Would not try it with my '69 Chevy, power brakes and steering wouldn't work. It has tried all by itself, freaked me out.

 

[accordman]

I draft trucks so hard the Collision Mitigation Braking kicks in #boss

All joking aside, a lot of hardcore hypermiling tricks are just insane.

Most of them compromise safety over a few MPGs. However, I do follow the "drive as if you have no brakes" rule which does save me from stopping at a red light too early and saves wear and tear on the brakes.

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