2006 Honda Insight MT Build Thread

[Ecky]

Mating the GM engine and Honda transmission together would be... difficult.


And yes, warmup seems to be the key to it, everything else is just details if it's running cold.

[Ecky]

Originally Posted by 19bonestock88

The guy said there was a pretty big step between 1st and 2nd gear...

There is. And the difference between 2nd and 3rd is also huge. 3-4-5 are pretty close together.

There are quite a few areas where I live where I just can't climb a hill in 3rd gear, but 2nd would be revving at 4-5000rpm because the drop in RPM is close to 50% between the two. More linear gearing would be ideal, but the car is still very drivable with the weird gear spacing Honda chose.

[mpg_numbers_guy]

Originally Posted by 19bonestock88

You said your IMA could be fixed just by fixing ground straps? Hell yeah!

That and replacing the 12V battery, but I'm hoping so! Got my fingers crossed there

Originally Posted by Ecky

Mating the GM engine and Honda transmission together would be... difficult.

Quit killing my enthusiasm!

Originally Posted by 19bonestock88

The guy said there was a pretty big step between 1st and 2nd gear...

Originally Posted by Ecky

There is. And the difference between 2nd and 3rd is also huge. 3-4-5 are pretty close together.

There are quite a few areas where I live where I just can't climb a hill in 3rd gear, but 2nd would be revving at 4-5000rpm because the drop in RPM is close to 50% between the two. More linear gearing would be ideal, but the car is still very drivable with the weird gear spacing Honda chose.

There is, but I haven't had a problem with it. There seems to be plenty of power in 2nd gear - I've shifted from 1st to 2nd where 2nd starts off at 1000 RPMs and have been fine, even on an incline. I haven't driven on any super steep hills yet with the Insight, but I know some hills are steep enough where higher RPMs are necessary regardless of gearing, but such hills aren't common enough to necessitate an entire transmission change. The stock Honda gearing seems to be optimized to accelerate acceptably while using as little fuel as possible. By 2nd gear I'm basically guaranteed 25 MPG no matter how hard I accelerate, which is 2-3 times as efficient as the Civic ever was, and even better in higher gears.

We have a few steep-ish hills, but not THAT steep...I generally have the gas pedal depressed enough in 5th not to lose more than 5-10 MPH. "Worst" that's happened is I've gone from 51 MPH to 37 MPH with it floored, getting 50 MPG. Usually hills are 50-70 MPG. I've downshifted to 4th once while climbing a hill. Losing speed and gaining it on the flat or downhill is much more efficient than downshifting (4th gear floored is only 35 MPG I think?). I'm sure our hills are different though; I haven't been to Vermont but I know areas of New York can get pretty hilly.

I just need to get my cruising MPG up. Right now the stars have to align to get above 85 MPG cruising speed for more than a mile if it's flat.

[Gasoline Fumes]

Originally Posted by Ecky

So I was thinking, I lose lean burn when I plug in an Arduino which tells the computer the hybrid battery is empty. One way to solve this is to tell the car the battery is not in fact empty, as long as I'm moving at more than ~22mph (otherwise I'd get auto-stop with no IMA, which is very bad when driving around town), and to have it switch over to saying the battery is empty when I get below a certain speed so as to prevent auto-stop. I tried this for a while and while it works, it doesn't work all that well.

However, the IMA system also disables auto-stop under two other conditions: when outside air is below 40F, and when the climate control is set to "auto". I'm thinking I might feed the computer a 50% battery signal all the time and disable auto-stop by either telling the computer it's cold outside, or by figuring out what signal the climate control sends to keep auto-stop off. I suspect it's actually just going to require cutting a wire.

I was thinking about that too. Maybe cutting the BRN/YEL Heater standby signal (HTRS) wire?
https://www.insightcentral.net/forums/125971-post6.html

[Ecky]

Originally Posted by Gasoline Fumes

I was thinking about that too. Maybe cutting the BRN/YEL Heater standby signal (HTRS) wire?
https://www.insightcentral.net/forums/125971-post6.html

I was thinking of measuring the ENGRDY wire to see if that was the one, but this is a great lead. Thanks!

I may not have to do anything though. Hopefully I'll have a different engine before it's warm enough to get auto-stop again.

[mpg_numbers_guy]

Gasoline Fumes, are you bypassing the IMA on your Insight?

[Ecky]

So I notice that with my arduino bypass plugged in, the engine "feels" different with the check engine light off. Idle is a hair lower and there seems to be less torque at low RPM. I suspect the engine map is different when the check engine light is on. Logic would suggest that it may be partly responsible for lower fuel economy.

[mpg_numbers_guy]

What was your idle before and after compared to with the IMA? Idle for me is around 900 RPM both with the IMA working and with the IMA light on/BCM unplugged. Is the idle smoother at all without the CEL? I remember people mentioning that the Insight idled a little rough without the IMA.

Do you mean lower fuel economy with the CEL on, or with the bypass that prevents the CEL?

[Ecky]

My idle with the CEL is 900-1000. Without, it's more like 800-900 - or around one bar lower. I haven't done enough side-by-side testing but I speculate fuel economy is better when there's no CEL.

The normal IMA bypass tells the computer the battery is empty, which also results in a higher, smoother idle of 1100-1200 as the computer expects the extra load of charging an empty battery to be dragging on the car. My current bypass is instead telling it the battery is half full right now, which means if the weather were warmer I'd be getting unwanted auto-stop. The engine is running a map expecting normal regen and assist, which stands to reason to be the most efficient one.

[Ecky]

Datapoint for you:

Got a fresh 100% grille block installed yesterday (upper and lower), in addition to the WAI. Drive home today was around 11 miles, all stop and go traffic. Outside temperature ~34F, snowing lightly. Running the heater at a low setting the car was barely shy of fully up to temperature. Air intake hit around 80F toward the end. Fuel economy ~60mpg.

Best image I have, I get home after dark every day: