[jameskb]

Hey Insighters;

I have about a 10 mile stretch of road where I drive 35-50mph with lots of little hills and a 35mph zone to slow down in.

I find that when I stay in 4th gear, don't go to 5th gear (at 35-50mph speeds) and ignore the "upshift diamond", that I can achieve better mpg on the bargraph and better overall car response. That is, I drive the stretch of road never going to 5th gear "as instructed" by the car, and I can do way better on mileage at 35-50mph, often reaching up into the 80-100mpg range for that stretch of road.

On a downward incline, I can still hit 150mpg if I upshift into 5th gear, but that works only for a long, gradual incline, and if I'm not up to a reasonable road speed (and have cars behind me) it's a bad move because you can't accelerate at all in 5th gear from down around 35-40mph. But if I stay in 4th, I can get to 100mpg or better and still be able to accelerate if I need to.

Just thought I would float the idea of denying the diamond. I don't recall seeing this discussion anywhere. I was a little surprised by this, because I've always trusted the diamond to get me best gas mileage, but here I am finding out otherwise. Anyone else seeing this?

Thanks;
JKB

 

[Insightful Trekker]

Its buried somewhere in one of the old Yahoo Insight groups.

One of the finer points of maximum MPG Insight driving.

Welcome to the over 70 MPG club <g>

John K. Bullock
Knoxville, TN

aka. Insightful Trekker

 

[Tim Maddux]

I find the upshift arrows to be helpful for newbies but quickly learned that they weren't helpful at all for really good mileage (the kind that beats the EPA ratings). In particular, I accelerate hard, and upshifting when the car requests would defeat that.

These tips are much more useful:

http://www.insightcentral.net/KB/faq-efficiency.html

 

[jameskb]

Diamonds Aren't Forever

I find the upshift arrows to be helpful for newbies but quickly learned that they weren't helpful at all for really good mileage (the kind that beats the EPA ratings). In particular, I accelerate hard, and upshifting when the car requests would defeat that.

These tips are much more useful:

http://www.insightcentral.net/KB/faq-efficiency.html

Tim;

The FAQ is not relevant to my query. Note that the terrain I'm talking about (a windy, hilly country road with some low speed limit zones) is key to the question and is a specialization not addressed in the fuel efficiency techniques section.

I'm asking for those with experience in this type of terrain to please reflect back to me on your experiences. I found it surprising that cruising in 4th gear could give better mileage at lower speeds. This does actually contradict the FAQ at one point. Hence my question to the group: I am seeking feedback from others' experience.

I challenge you and the rest of the group to try it and provide experience-based feedback. It's possible we might be able to add to the FAQ based on what people turn up.

JKB

 

[Willie Williford]

Deny The Diamond.

I've ignored the "diamond" since day one. I very seldom get below 2,000 rpm after getting up to speed and have a lmpg of 59.6 for 68,000 miles. I have to run it hard in the mountains of southern Calif. Preferred rpm to me is around 3,000. Still get good mileage and right at the point for good power for passing those slow suv's......HA HA.

 

[jameskb]

Re: Deny The Diamond.

I've ignored the "diamond" since day one. I very seldom get below 2,000 rpm after getting up to speed and have a lmpg of 59.6 for 68,000 miles. I have to run it hard in the mountains of southern Calif. Preferred rpm to me is around 3,000. Still get good mileage and right at the point for good power for passing those slow suv's......HA HA.

Willie;

Sweet. I'm glad to hear it. Sounds like the diamond gets used less and less by the experienced drivers, and running at minimum engine rpm's may not always be the way to hi miles.

JKB

 

[Tim Maddux]

Ok... I had only skimmed your first post... more specifically...

5th gear is often not the best choice at low speeds / low RPM because the car will start lugging, and won't have the power to maintain your speed while still in lean-burn mode. It's been my experience that a lower gear often will.

I do my 5-mile daily commute at about 30mph in 3rd gear, occasionally but rarely hitting 4th if I take a slightly different route, almost never 5th. I can routinely beat 70mpg on daily 10-mile trips when the weather isn't bad.

On the downhills you can probably do better by upshifting to 5th and letting fuel cutoff mode (regen) engage, then downshifting when you need boost again. 5th gear regen/cutoff won't put as much drag or slow you down as much as lower gears. Or put it in neutral if you want more speed, depending upon the particular hill.

 

[jameskb]

Ok... I had only skimmed your first post... more specifically...
...
I do my 5-mile daily commute at about 30mph in 3rd gear, occasionally but rarely hitting 4th if I take a slightly different route, almost never 5th. I can routinely beat 70mpg on daily 10-mile trips when the weather isn't bad.

On the downhills you can probably do better by upshifting to 5th and letting fuel cutoff mode (regen) engage, then downshifting when you need boost again. 5th gear regen/cutoff won't put as much drag or slow you down as much as lower gears. Or put it in neutral if you want more speed, depending upon the particular hill.

AWEsome stuff there Tim, and exactly the kind of thing I was looking for. Would I be able to tell if I'm in fuel cutoff mode if I switched the FCD to L/100km?

JKB

 

[Tim Maddux]

Would I be able to tell if I'm in fuel cutoff mode if I switched the FCD to L/100km?

Yes... in MPG you won't see anything greater than 150 mpg. In fuel-cutoff mode you don't burn any gas and the indicator will display 0 L/100km if you switch to metric, which is infinite mpg.

 

[Rick Reece]

Hills

I drive on rolling Hills for a good portion of my drive and I do not downshift. One of the nice things about the Insight is that the engine will get an electric assist on a incline if it needs the extra hp to maintain the cruise control speed. This allows the engine to stay in its top gear ratio even when it doesn't have the power to maintain speed without the electric assist
On very hilly terrain I let the speed increase on the downgrade and and let the momentum carry me up the hill. If done right you can stay in lean burn all the way up the incline. Have fun, Rick

 

[Guest]

Hi All:

___I denied the diamond a few times this afternoon and my results were very positive … Although I can use assist in 5th when climbing hills and maintain lean burn, I have to have my speed up (45 mph + or thereabouts) or I will drop out unexpectedly. I am a brand new Insighter so I am just trying to hone a technique that works for me.

___As an example, there is a shortcut I take through the Gurnee Mills mall in Gurnee, IL. I stayed in 3rd with a speed of ~ 30 mph through this malls outer drive and still had an instantaneous showing 80 - 85 mpg while the diamond wanted me to upshift. I did the same through my subdivision and saw the same effect at 25 - 30 mph speeds in lean burn w/ > 80 mpg on the game gauge. I could not have achieved this result in 5th.

___With that, I am almost wondering if the 1-2-5 shift pattern from a stop is the best way to accelerate given lean burn capability is available in 3rd and can be achieved faster? Does anyone want to add to this or have done something similar w/ good results?

___Another question to go along with 3rd gear lean burn capability. If VTEC kicks in at 2500 RPM, wouldn’t it be better to keep your RPM’s on initial acceleration below that area if possible? I know it provides power but I am wondering if it doesn’t also take away from total fuel economy? If it does, a 1-2-3-5 with RPM’s < 2500 RPM on initial acceleration might provide better overall fuel economy and possibly faster acceleration to hwy speeds as well? That is if you don’t jump on the 1L at 5K + between shifts? I just can’t put my foot to the floor as generally practiced yet still receive > 70 mpg in a segment at less then 2 miles from the start of my trip with a cold engine. The assist gauge only shows 1/3 to ½ the bars lit when I accelerate in this manner …

___Good Luck and Thanks in advance.

___Wayne R. Gerdes
___Hunt Club Farms Landscaping Ltd.
___[email:3gf6pvcs][email protected][/email:3gf6pvcs]

 

[windmill]

Km/h to Mph

I have read this post for a little while but.....:
Is there a way to built in the "miles switch", I do only have km/h mode only in my car, no switch there!!!

Greetz Windmill :? :?

 

[The Citrus Smoothie]

Windmill - You have the same problem as me, except I believe my Insight was 'chipped' when imported to show MPH and meet regulations. My dashboard Km/H symbol has had to be covered up. I doubt we could easily have the MPH/KmH switch installed; but aren't your national measurements in Km anyway?

 

[windmill]

Diamonds are forever....

The Silver Striker has a point here! I am gonna look in the schematics how everything is wired up.

Greetz Windmill :wink:

 

[figgy]

You are describing my observations!

I've only been driving a short time, but it felt exactly like what you are describing - that upshifting following the diamond was always making the engine lug and never giving me very efficient acceleration. To me, that seemed like a recipe for low mpg, and your comments seem to prove that to be the case.

My general thought was that if I just drove it like I would a regular stick, i would end up with better mpg than obsessing on the diamond. Only the driver knows the road ahead, and the car is just guessing based on its instantaneous data with no ability to predict an upslope, downslope, or anything else about to be encountered.

I started a thread in MPG Issues specifically about this, so if anyone has more experience to add, please post to that thread.

It seems like a tremendously important issue, but not really discussed as thoroughly as other issues.