[FinalHeven]

I'm not an owner, but a young enthusiast. I'd like to buy an insight when I'm out of college. I just had a couple questions. When accelerating on the highway, does the 1-2-5 shift method apply, or should all the gears be used? For all cars, what do you think the most efficient speed is? 50? 55? 60? Go ahead and give me some values you've found for the Insight as well. Thanks! I'm looking forward to the replys.

-Mike Hinton

 

[Rick]

I've tried the 1-2-5 method and decided it was way too much load on everything. On the highway I usually don't bother with 4th, use 3rd for passing, it's good till 113mph. 2nd occasionally for very aggressive passing at sub 64mph speeds. As far as most efficient speed thats really, in general, the speed in which you enter your top gear. For the Insight that is about 35 mph where you can hold about 125mpg instantaneous. Realistically 55 is probably the most ideal for not being ran off the road too badly. I cruise at about 60 and can get numbers in the upper 70's lower 80's. The thing to do is just find a pedal position that will hold about 60mph on level road and keep your foot there and let your speed varry on hills and such. Anything faster than about 65 in the Insight and wind drag out powers what the engine can put out in lean burn mode so you have to burn more fuel to keep the speed. But still, even at 80mph you can still get 55mpg.

 

[Insightful Trekker]

The 1-2-5 method has the potential for maximum MPG but at a price. For my driving I go into a forced recharge too often. My topography and commute dosen't lend itself to enough regenerative braking for this upshift pattern.

There is an official HONDA publication, maybe the Service News, that specifically addresses this issue. The synchro mesh rings of MT transmissions act as mini clutches to bring the gear set in sync with the shaft speed as the gear is engaged. This eliminates gear raking when up shifting / down shifting. Skipping gears requires much more work from these parts and premature wear is predicted.

John K. Bullock
aka. Insightful Trekker

 

[Willie Williford]

fuel efficiency questions

Shame on you Rick, 113mph in 3rd? Don't think so. 4th gear at 113mph for sure, as I have done that, but not 3rd. I've pulled 113 in 5th @4000 rpm. The Turbo pulls strong at that point, but the speed limiter is kicking in. Don't think I want to go any faster, .......Willie

 

[Tim Maddux]

Most people who have reported reaching the max. speed of the Insight have done it in 3rd gear, not 4th or 5th... check the Yahoo! honda-hybrid and honda-insight forums.

I shift 1-2-3-5.

In any car driving at speeds where wind resistance is important, the drag coefficient is constant and so the drag on the car goes up as velocity squared. If you double your speed, you quadruple the force on the car. That in turn means you have to burn more gas to stay at the same speed. So slower is more efficient, until you get to a point where the engine RPMs are too low and it starts to lug.

With the Insight in particular you will have a sharp dropoff at higher speeds when the car cannot maintain lean-burn mode to keep the car moving. Also, rather than driving at a steady speed most Insight drivers who get high MPGs choose to drive either at a constant throttle setting, or at a constant (or nearly so) instantaneous MPG, allowing the car to slow a little going up and accelerate back down. The car is much more sensitive to even slight grades that you wouldn't even notice in other cars, and by trying to maintain speed up a hill you can wind up losing lean-burn mode. Average MPG is nonlinear, so if you lose lean-burn up the hill it's hard to make it up on the way back down.

Hope this helps! Try reading the mileage tips in the knowledge base.

 

[Will M]

The 1-2-5 method has the potential for maximum MPG but at a price...
There is an official HONDA publication, maybe the Service News, that specifically addresses this issue. The synchro mesh rings of MT transmissions act as mini clutches to bring the gear set in sync with the shaft speed as the gear is engaged. This eliminates gear raking when up shifting / down shifting. Skipping gears requires much more work from these parts and premature wear is predicted...

I use 1,2,5 a lot, just because it is fun. I did it in my 1992 Civic years before I got the Insight. 210,000 miles later, the synchro mesh rings are still working, so I think Honda underestimates the ruggedness of their engineering.

Case in point: My Honda dealer offered me an orientation with a Honda-trained mechanic when I bought the Civic. He told me I should never let the gas guage get below a quarter tank because the fuel pump has to work harder when it doesn't have the weight of a fuller tank to back it up. Ignoring this would require premature replacement of the fuel pump.

I always figured that gasoline has weight, and likely, my best gas mileage occurs while the gas tank is nearly empty, so I've made an art of driving until the guage is burried so deeply at E that it won't move on curves. I'm always a little disappointed in myself if I fill up with less than 10 gallons. Again, 210,000 miles and the fuel pump is still doing its job.

I always figured that my fun, excessive accelleration happens rarely enough that my fixation on the MPG guage the rest of the time makes up for it. Engines like varied driving. Enjoy blowing out the carbon now and then, and spend the rest of your time letting the MPG meter teach you how to drive to save gas.

The two worst MPG sins are:

1. Excessive top speeds. Most of your miles are spent at top speeds, so the accumulated effect is big.

2. Ignoring tire pressure. This effects every mile you drive.

Beyond that, the car will teach you the rest. A few miles of fun now and then won't do much damage to your LMPG, and much of MPG is out of your control: wind, temperature, driving surface, traffic, stop lights, hills, fuel quality, distance to destinations, rain, snow, weight of passenger, etc..

 

[gomarlins3]

I have noticed that I get much better milage as the fule level drops. I never thought the weight of the fuel would ever have that much effect, but it does.

 

[The Citrus Smoothie]

Re: fuel efficiency questions

I've pulled 113 in 5th @4000 rpm. The Turbo pulls strong at that point, but the speed limiter is kicking in. Don't think I want to go any faster

I understand that it was hard work installing the only turbo on an Insight, for which I give you congratulations. However, I hope you have removed the speed limiter at least once, to show yourself (& the rest of the world!) what the new top speed of your Insight is?

 

[The Citrus Smoothie]

Re: fuel efficiency questions

I've pulled 113 in 5th @4000 rpm. The Turbo pulls strong at that point, but the speed limiter is kicking in. Don't think I want to go any faster

I understand that it was hard work installing the only turbo on an Insight, for which I give you congratulations. However, I hope you have removed the speed limiter at least once, to show yourself (& the rest of the world!) what the new top speed of your Insight is?

 

[ncnightowl]

I have noticed that I get much better milage as the fule level drops. I never thought the weight of the fuel would ever have that much effect, but it does.

I get max mpg on a FULL tank.. 1st 30 miles or so instantaneous meter will read higher than usual with corresponding increase in mpg.

 

[Rick]

Re: fuel efficiency questions

Shame on you Rick, 113mph in 3rd? Don't think so. 4th gear at 113mph for sure, as I have done that, but not 3rd. I've pulled 113 in 5th @4000 rpm. The Turbo pulls strong at that point, but the speed limiter is kicking in. Don't think I want to go any faster, .......Willie

What? The rev limiter in 3rd gear is at 113mph. It actually holds it there quite gently. The car says screw you after that, it won't go any faster. Tried it in 5th too, it just pulls to 113 and then just quits pulling. Well, actually if you have a 2000 or 2001 with a non replaced ecu it will, a speed limiter was just one little added feature they provide you with when you get the updated ecu.

 

[Will M]

Speed limiters have been with Honda for a long time. My 1992 Civic toggles the ignition once you hit red-line, holding the engine at that speed. There's no tachometer, but then you don't need one, since you can't drive past red-line.