More efficient to cruise at a higher RPM?

Andre80

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it's not true. the optimal consumption is obtained at a certain rpm
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ASH_CTR678

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Being that the Type R powerband starts around 3000 RPMs, you probably will see more fuel savings if you aren't on completely flat ground. If you are operating at some suboptimal range of the engine, it can only dump more fuel to provide torque. Since roads are never completely flat, at some point while you are cruising, your engine will need more torque to maintain speed and go up an incline.....which is where your car will burn more fuel. If you go up the hill when the engine is at its optimal powerband, it should be more efficient. I've included an image below of a stock Type R dyno output.....and you can see the engine puts out about half the torque at 2300 RPMs vs 3300 RPMs. I believe the way to look at it is, the car is putting out twice as much torque for only 43% more cycles. You would need the difference in cycles to be more than the torque to lower your fuel economy.

I usually try to keep my car over 2500 RPMs at all times unless coming to a stop. I've notice when on cruise control, if I am running around 3000 RPMs, the fuel economy gauge doesn't drop as much on inclines as when running lower than 3000 RPMs on inclines. And as you go above 3000 RPM, the fuel mileage I get per tank on long haul drives tends to start to decline by an MPH or two.

If you were going down hill, it probably wouldn't really matter if you ran the car at 2000 RPM or 6000 RPM (assuming a steep enough hill), since gravity would be accelerating your car and the drag from the engine would be slowing you down to maintain a certain speed. There is another Engineering Explained video where he compares coasting vs keeping a car in gear when slowing down. While one would likely think coasting would be optimal, keeping the car in gear to slow down actually consumes less fuel, too.
Honda Civic 10th gen More efficient to cruise at a higher RPM? 203-TestandTune-CivicTypeR-001-chart
 

eshults5

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Change the gauges to the one that shows throttle percentage. IDK if the type R has it, but my si did, I will check next drive.

Separately use cruise control to take your foot on the accelerator pedal out of the picture.
It does. I greatly utilized this view to better understand the car when I first got it.

Personally, it feels like this car WANTS to drive around the 3000 RPM mark. Very different from my V6 accord which I always felt cruising between 2 and 3k rpm
 

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Was paying more attention to my shifting habits and I am within the 3k to 4.5k rpm band when accelerating.

When cruising at freeway speeds I’m at 2.8k to 3k in 6th gear.
 

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About midway in the video where you see 4 different rev ranges all going at the same speed if i remember correctly it looks like a slightly higher RPM is more efficient as some of you have mentioned.
No it isn't.
Honda Civic 10th gen More efficient to cruise at a higher RPM? upload_2020-2-10_16-23-20


I'll say again, the least throttle required to maintain a given speed, irrespective of gear. Also consider inclines and declines can affect which gear is most efficient. Traveling up a steep grade in 6th gear at 40 mph probably is not efficient.

I tried using cruise control with the throttle position indicator in the cluster and yea it doesn't seem to work. But the live mpg gauge is just as good and probably preferred anyway for this particular test.
 
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JoYu

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It does. I greatly utilized this view to better understand the car when I first got it.

Personally, it feels like this car WANTS to drive around the 3000 RPM mark. Very different from my V6 accord which I always felt cruising between 2 and 3k rpm
Yeah it will have a lot more pep when it's at a higher RPM, but it may or may not be in it's most efficient zone ;) We can use the throttle gauge to tell what gear uses the least fuel.

There are things hypermilers do to get better gas mileage like always coast or be speeding up, so on the freeway they speed up from like 60 to 70, coast down to 60, speed up...

I just drive my car though, if I was worried so much about gas mileage I wouldn't have upgraded to the type R :)
 

Fred_Farkle

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I used to cruise at 2300ish RPM when commuting, but the engine always felt so meh when I applied throttle (not WOT) without downshifting. Lately I started cruising at around 3300 RPM instead, and the engine feels much more responsive and much more eager. Interestingly enough, I had thought my fuel economy would drop slightly from cruising at a higher RPM but it really hasn't. It's also way more fun shifting at 4.5k or higher :headbang:

(Disclosure: Despite owning it for almost 2 years I still don't drive it that hard... that's slowly changing as I realize that it makes the car far more enjoyable)

The only negative is my cabin is louder with a slight drone (HKS exhaust, not OEM), but it's nothing that would drive me insane.

Any other's thoughts on this? I thought I remember something about smaller displacement engines actually being more efficient at higher RPMs.
I find I get (according to the Economy Meter on the Dashboard) slightly better fuel economy at 50 mph in 4th gear at 3K RPM as opposed to 5th at about 2.6 K. I feel like it lags in 5th.
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