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Discussion Starter #1
Hello all,

Had a question regarding MPG speeds. I took the Insight on the Interstate and my son had to get to the airport. As usual he was running late so I had to pick the speed up on the Insight to around 65 as the speed limit was 65. I usually do not drive any faster than 55. I noticed at 65 MPH I was averaging about 49 MPG.
Once I dropped him off, I drove back home at 55 MPH and seemed to be getting much better MPG, like 54 MPG.
It almost seems to me that the Insight likes the 45-50 MPH speed to get maximum MPG? I was getting almost 62 MPG at that speed on local roads. Any thoughts on this?
 

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You run out of gearing at 45 mph. So any faster than that you use engine rpm vs power to reach your desired speed.
 

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So many variables. Temperature, terrain, wind, dry vs wet weather, physical road surface condition, traffic type, driver patience, vehicle condition, to include tire pressure, load in car, and type of oil in crankcase, among others.

In most situations, I see best MPG in the 40 to 55 mph range when I'm in the Insight. Our Prius can get better MPG in urban driving situations, so speeds down in the 35 to 45 mpg are nearly optimal for that car. I'm a fairly patient driver, and look way ahead to anticipate acceleration and braking/coasting. Steady accelerator, and steady wheel. Compared to other Prius drivers I know, my driving technique gets me a good extra 4-5 mpg in the Prius and way better tire longevity, too.

I know several people who drive Prii, even family members, so it's easy to compare notes. I know people who have more than one Prius in their garage. Can't compare MPG numbers with other Insight drivers locally. Have no acquaintances or family members that drive Insights. Don't normally see that many Insights around our area, even.

That has to be due to the incredible job Honda did marketing this car!
 

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Good point. Are we setting the cruse control and just steering down the road or is this a contest? :evil: The better way is to pulse n glide as that can expose the engine to the sweet spot as the cvt cant lug the engine enough on level surface with fully inflated tires and little to no wind.

Just think to the graph you may see with the circles in it showing load vs efficiency of an engine. You want the car to be in one of those spots.
 

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Discussion Starter #7
Real good explanations. I did notice that the temp variables are also in there as the car will react differently in different climate conditions affecting things like auto-stop, etc. You guys are a wealth of information! Thanks
 

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There is a technical threshold - actually two: the maximal ratio of the CVT and the minimal RPM at any speed.

When the CVT maxes out I get 20 times the RPM per km/h (32 times RPM per mph).
So at 100 km/h (62 mph) the engine does 2000 RPM, at 60 kmh it does 1200 RPM.... but below 55 km/h (34 mph) the RPM will sink no further.
Go any lower than that in speed and the engine will have to turn over more per distance covered.

I do have a 5 km stretch of flat rural road with a speed limit of 60 km/h in my commute (as an option).
On a warm and windless day I can see the instant FE reading drop as low as 2.6 l/100 km for miles on end when doing 58 km/h (35 mph).
I cannot get that low on the freeway, even when drafting trucks at 50 mph.
(as always I mean drafting at a safe distance of over 2 seconds away)

I believe the sweet spot is around 58 km/h (35 mph), driving a constant speed at just over 1100 RPM.
I tried P&G-ing but it does not seem to improve economy, at least not at that speed.
But 2.6 l/100 km (about 85 mpg) is nothing to be ashamed of.
 

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Discussion Starter #9
Red Devil,
Interesting, I notice that going 55 mph, I do fairly well depending on wind conditions, etc. There is a video of a guy Hypermiling with the Gen 2 version on Youtube. Check it out if you get a chance. Looks like he is going like 55? He got like 70 MPG on the vehicle. Wow!
 

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AAMOF I drove that same road this afternoon, wet road, no rain, 6°C / 42°F, mild wind aft, but not straight aft.
I kept it below 3.0 l/100 km all the way until I had to wait behind some bicyclists for the oncoming traffic to pass us (narrow road).
So even in these less than optimal conditions I can get about 80 mpg driving 35 mph by cruise control.

If you want to go faster and still have good FE you need special conditions, like a good draft from a semi or a tight pack of traffic.

I am pretty sure that if you'd let me drive in circles inside a stadium or so I could get over 1500 km / 900 miles on one tank driving my car just as it is.
If I set the tire pressure to over 50 PSI, block some more grill, leave the lights, A/C and stereo off and dump anything removable that isn't needed to keep the car moving then over 1000 miles on a single tank is entirely possible.
I'd need more than 24 hours, but I would make it.

Driving out in the wild (i.e. my daily 22 mile commute, part city, part highway, part rural) I have yet to beat my goal of over 1000 km (600 miles) per tank. I've been close; had the chance more than once but either chickened out or took advantage of a special discount...
But things are looking good lately. The winter slump is less than usual, if I can keep this up in summer I'll beat it :)
 

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Discussion Starter #12
I am not sure when you got your car and if you are just getting used to it or not. I have to tell you in the beginning I found the same problem but between the side view mirrors and the rear hatch I have gotten to know where to look for the blind spots. I am pretty good with the car now but if you find that you are still having a problem I have been told that those stick on fish eye mirrors are a good addition to the side views. Best of luck with your car!
 

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It is dead off topic (which is about best speed for economy) but indeed you can improve visibility by setting the side mirrors so that you can hardly see the car, to max the side view angle.

Also I put the rear view mirror in its highest possible position (it is on a double ball joint) and raised my chair; that improves both what you see in the mirror and over your shoulder.
The spoiler bar is then further below the horizon.
Raising the chair improves leg room in the rear a bit.

Before I realized I could raise the mirror I had the chair in its lowest position as otherwise the rear view mirror would block my view ahead... :)
 

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...When the CVT maxes out I get 20 times the RPM per km/h (32 times RPM per mph).
So at 100 km/h (62 mph) the engine does 2000 RPM, at 60 kmh it does 1200 RPM.... but below 55 km/h (34 mph) the RPM will sink no further.
Go any lower than that in speed and the engine will have to turn over more per distance covered.

I do have a 5 km stretch of flat rural road with a speed limit of 60 km/h in my commute (as an option).
On a warm and windless day I can see the instant FE reading drop as low as 2.6 l/100 km for miles on end when doing 58 km/h (35 mph).
I cannot get that low on the freeway, even when drafting trucks at 50 mph.
(as always I mean drafting at a safe distance of over 2 seconds away)

I believe the sweet spot is around 58 km/h (35 mph), driving a constant speed at just over 1100 RPM....
Right on !

Have found 35 - 50 mph to be best speed range. 40 mph better than 35, near 50 mph even better in some road / traffic conditions.

Drafting other vehicles is difficult because many drivers do not drive steadily. So often wonder if I'm actually saving anything with all the speed-up slow-down often necessary to maintain the following distance. It becomes an effort to find a vehicle vertically equal to or higher than the Blue Bird AND has a driver willing to travel at a steady pace (ignore slowing for hills or slow increase of speed on downgrades).

Have found the effort worthwhile at 65+ mph and head wind of 20 mph or more though. The amount of mpg benefit seems to be enough to negate the mpg loss due to the head wind.
 

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My Observation

2014 Insight:
Interstate speed here in Texas generally seems to be 65 -85, so the 45-55 is pretty much out.
My experience with the Hybrid (seat of the pants and watching fuel dials,) would indicate the 2014 likes a little tailwind and speeds 80-85. It seems to have enough velocity to carry itself well through the valleys and up the hill. There are times I can back almost all way out of the throttle just over the peak and well into next hill. Wife does not like to drive the Insight as it "goes too fast" And prefers her little red Fit.

At 45-55 engine is always "loaded", albeit light, with a pull" up a hill.

Just a newbie here, first posting, first hybrid, but have owned the brand (think) almost continually since (new)86 dx hatchback 5 speed (that would flat fly.)
 

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My Observation

2014 Insight:
Interstate speed here in Texas generally seems to be 65 -85, so the 45-55 is pretty much out.
My experience with the Hybrid (seat of the pants and watching fuel dials,) would indicate the 2014 likes a little tailwind and speeds 80-85. It seems to have enough velocity to carry itself well through the valleys and up the hill. There are times I can back almost all way out of the throttle just over the peak and well into next hill. Wife does not like to drive the Insight as it "goes too fast" And prefers her little red Fit.

At 45-55 engine is always "loaded", albeit light, with a pull" up a hill.

Just a newbie here, first posting, first hybrid, but have owned the brand (think) almost continually since (new)86 dx hatchback 5 speed (that would flat fly.)
 

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I posted on another thread that I filled the tank yesterday. Low fuel light was on. Was not able to fill at the same pump (had a Bag over it) so I did use the one next to it. Incline was the same, and I filled to neck very carefully. My tank to tank was 58.8 mpg. My MID indicated a tad over 61 mpg.

I did intentionally drive back roads, 35 to 50 mph, but probably 45 mph most of the time. Drove 3 short segments on the Interstate... under constructions/repair so posted was 60. Also did some rush hour travel.

So far the "sweet" spot is tending to be 40-45 in most cases. Going to try to beat that 58.8 mpg with this tank. Learning how to get the most out of the Insight's efficiency.

I found some small convex stick on mirrors to help with the side view. They are about 1 inch tall and 2.5 inches wide, plus they adjust. They're great for extra field of vision.
 

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That 58.8 beats my best tank to tank (56.5). Congrats!!
 

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I have to set my MPG expectations at 42 because, in France, the highway I drive twice a week is very windy, full of hills and the average driver runs at around 135 km/h (83 mph). I know, it's insane and for safety's sake I have to keep up... So my "sweet spot" is around 110 km/h (68 mph) and I stress out every time I have to pass a semi. My Fuelly dashboard is depressing.
 

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Yes, driving conditions are what they are. My commute is all uncrowded back roads that don't require driving more than 35-45 mph for the most part. Easy driving.

Unfortunately some of us have to drive some pretty fast commutes. Not safe to slow up traffic. Just imagine what most other drivers in non Hybrid gasoline/petrol cars are getting for MPG under those same fast paced conditions.

Lots of money vapor out the tailpipe!!!
 
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