Honda insight, doing research, interesting trends

[NoCO2]

So, I'm doing some research into getting a more fuel efficient car. Right now, the most appealing thing is a Honda insight. However, doing some research showed an interesting trend in their fuel efficiency. It appears to change between years. The results are as follows using the new EPA estimates, formatted in city/highway/combined. (source: www.fueleconomy.gov)

2000 - 49/61/53
2001 - 48/60/53
2002 - 48/59/53
2003 - 48/59/53
2004 - 48/58/52
2005 - 48/58/52
2006 - 48/58/52

All these were using the base model with the 5spd-manual transmission. It seems that the efficiency has gone down, however slightly, in the last 6 years...what could have attributed to this? I'm not very familiar with how the EPA estimates their gas millage, but I think I have an idea, which is that it's based on a national average speed for city and highway driving, taking into account stop and go. So does this mean that the average speed went up over the course of 6 years or did Honda change something that slightly effected the fuel efficiency of their car?

I'm just wondering because I'm looking to getting one and I want to make sure I start with the one that gets the best millage if there is a significant difference or change in a particular year model that I should know about before purchasing any one year.

[Daox]

The EPA testing did not change over the 6 years. Something must have been changed with the car.

[cfg83]

NoCO2 -

I would guess that the emissions compliance would be getting more stringent every year. Since the Insight uses lean-burn technology (right?!?!), it would have a tougher and tougher time meeting NOx limits.

This is just a guess, though.

CarloSW2

[NoCO2]

why would lean burn kill the emissions? I thought the idea of lean burn was to just use less fuel...wouldn't this make it's emissions score better?

Sorry, maybe I just don't understand this lean burn thing well enough.

[Daox]

Lean burn is great for fuel economy. But, it has the tendancy to produce Nox...

[cfg83]

NoCO2 -

Originally Posted by NoCO2

why would lean burn kill the emissions? I thought the idea of lean burn was to just use less fuel...wouldn't this make it's emissions score better?

Sorry, maybe I just don't understand this lean burn thing well enough.

From what I have read, classical lean-burn lowers HO and CO but increases NOx. Up until recently, this has been the big bug-a-boo with diesel in the USA (along with soot). When people talk about clean-diesel, they are usually talking about NOx traps and stuff.

For example, the Honda Civic VX hatchback from the early 1990's came in two versions, one for California and one for the rest of the USA. The California version got worse MPG because it couldn't invoke it's lean-burn technology (as aggressively?!?!?) without violating California emissions standards.

CarloSW2

[budomove]

2 things are possible.

They updated the battery condition monitor and motor control module in 2002 to increase battery life, but some say the change hurt mpg. dunno why the epa rating changed twice though.

They added a 3rd o2 sensor in '02, downstream of the 2nd cat.
Its purpose was to differentiate b/w failure of the 1st cat, and that of the 2nd.
On 00-01 models, the o2 sensor downstream of the 1st cat was the only indicator of cat failure, and you must still buy both cats when this happens, because there is no way to know whether one or both have gone bad. I don't know if the 3rd o2 sensor somehow has an effect on mpg.

prolly the bcm/mcm upgrade, and potentially the ecm upgrade they did had some effect, although it was designed to fix the faulty cat failure codes that resulted in many unneccesary cat replacements, that have since been reimbursed.

frank

[Ryland]

I know that one of the changes was in the spark plugs, the first year or two of the insight had copper tipped spark plugs that had to be changed every 15,000 miles or so, then they switched to iridiem tipped, or platium tipped or something like that, and altho they last 75,000-100,000 miles, they don't give as good of gas mileage, and being indexed spark plugs, alot of people didn't understand them.
I was thinking that later one they added something like side impact air bags, or something simaler to that, because the weight of the car went up by about 150lb's too I think.
There was something else differnt as well but I forget what it was, I think it was something that I read in the shop manual, one of those chiltons that covers all the cars over a few year span... am I the only one who reads those?

[NoCO2]

Ok, well that's a lot of info guys, thanks a lot.

I found a few '00 model insights for around $5k - $6k and I'm talking to my dad this weekend about possibly trading in my Camry for one since the Camry has been having a lot of maintenance issues just due to it's age and I am trying to convince him that the increase in fuel efficiency is worth it for both myself and him since if it benefits him he's more likely to go for it. We will see how it goes, but again, thanks for the info, I want to be as informed about this going into it as I can so I can present a good bit of info for him.

[budomove]

I have a 2000, and all years had the specially indexed iridium plugs. There are 4 types: A, B, C, and D. All 3 cylinders are B on my engine, but during production they tested each cylinder for required indexing (dependent upon manufacturing variation) Mine just so happened to all be the same.

And unfortunately, as much as I wished it did, the insight never had any airbags other than the two front airbags. I never heard that the insight gained weight, huh.

Anyone else have any ideas?