2006 Honda Insight MT Build Thread

[mpg_numbers_guy]

Originally Posted by Ecky

Lower grille block, warm air intake, ran a 120v outlet through the firewall so she can pre-warm her cabin, checked tire pressure, swapped out one more bulb for an LED. She gets pretty phenomenal economy - I think mid 40's when the weather is good. Haven't kept track lately.

Do you just have your WAIs pointed at the cat, touching the cat, or what? My setup was stuck at 60 F; I disconnected it today (still hooked up, just not pointed anywhere in particular) and it peaked at 76 F. Kinda baffled on how to get it to the 110 F necessary for better fuel economy.

Does she hypermile the Fit at all?

[Ecky]

I have use small ducting that fits the intake perfectly, and run it to just below the cat, very close. In summer I've seen intake temperatures as high as 160F, at which point I had to back off the ducting. I'm taking it directly from the intake box and wrapping it backward, under where my 12v battery would have been.

She short shifts her Fit and drives slowly. No EoC or pulse and glide, just keeps it at or under 55 and is in 5th gear as quickly as possible. That, and ~45psi in the tires. It's a nice little car, not looking forward to the day salt eats it.

[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.

[mpg_numbers_guy]

Originally Posted by Ecky

I have use small ducting that fits the intake perfectly, and run it to just below the cat, very close. In summer I've seen intake temperatures as high as 160F, at which point I had to back off the ducting. I'm taking it directly from the intake box and wrapping it backward, under where my 12v battery would have been.

She short shifts her Fit and drives slowly. No EoC or pulse and glide, just keeps it at or under 55 and is in 5th gear as quickly as possible. That, and ~45psi in the tires. It's a nice little car, not looking forward to the day salt eats it.

I was looking at doing that, and just clamping or retrofitting the 3" aluminum ducting that I have, but there's a drain-off or something connected to the OEM intake tubing that I wouldn't have connected if I did that; would that be an issue?

Mine was pointed at the passenger side of the cat. Maybe it's just my missing belly pan that's keeping it from warming up. What kind of intake temperatures are you experiencing with it in winter weather?

Nice going in the Fit. They're definitely good cars. Was one of my considerations when I was shopping for my Civic, but all the ones within a reasonable driving distance were too expensive.

[mpg_numbers_guy]

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.

Can't you use the arduino to change the MPH cutoff for Autostop to something like -1 MPH, so Autostop never occurs? If I remember correctly you said it was possible to change the "SOC" to where you could get Autostop whenever you put it into neutral, maybe something using that?

Also, where is the ambient temperature sensor located on the Insight? I want to move mine so Autostop isn't disabled under 32F..

[Ecky]

Originally Posted by mpg_numbers_guy

I was looking at doing that, and just clamping or retrofitting the 3" aluminum ducting that I have, but there's a drain-off or something connected to the OEM intake tubing that I wouldn't have connected if I did that; would that be an issue?

Mine was pointed at the passenger side of the cat. Maybe it's just my missing belly pan that's keeping it from warming up. What kind of intake temperatures are you experiencing with it in winter weather?

Nice going in the Fit. They're definitely good cars. Was one of my considerations when I was shopping for my Civic, but all the ones within a reasonable driving distance were too expensive.

That drain off is (if I remember correctly) a resonator - the flexible rubber tube that runs down under the headlight goes to a plastic box which has no other openings. Its function is suspected to be either to smooth out intake air pulses and level out torque (maybe subtracting some at 2000rpm and adding some at 1600rpm), or possibly to reduce intake noise. It's safe to delete, I haven't been able to tell a difference with or without it.

I'll get back to you with a picture of it. Hoping to get at least 100F when the car is warmed up, but I might not see much improvement at all with my short commute. That's what's primarily killing my economy compared to previous years - the car is hardly warmed up by the time I pull in to work.

And yeah, the Fit was expensive. $4,000 and it has 200,000 miles. They're outrageously reliable too though, and don't seem to have as many "quirks" as the Insight, which I think makes it a good car for her.

Originally Posted by mpg_numbers_guy

Can't you use the arduino to change the MPH cutoff for Autostop to something like -1 MPH, so Autostop never occurs? If I remember correctly you said it was possible to change the "SOC" to where you could get Autostop whenever you put it into neutral, maybe something using that?

Also, where is the ambient temperature sensor located on the Insight? I want to move mine so Autostop isn't disabled under 32F..

SOC = state of charge

So you can't actually change the computer's programming, it just spoofs signals, and in this case the most important one is the charge level of the battery. The standard Arduino bypass sends the ECU a "ready" signal from the IMA, but also tells the ECU that the IMA battery is completely empty. The ECU therefore doesn't request any assist and thinks the IMA system is taking care of charging the battery back up, so it never finds out it isn't present.

One nasty issue with getting unwanted auto-stop when the IMA isn't actually present, is that the 12v starter is completely disabled until you key off and back on. Ask me how I found out. So, if you get it in the middle of an intersection and it kills the engine, you have a good 5-6 seconds minimum before you can restart the car. I could see it being useful with Natalya's forced auto-stop at high speeds, but it's absolutely not a good thing to get below highway speeds without the IMA in place.

As for the ambient temperature sensor, you can see it if you peer down into that gap between the radiator/A/C condenser and the front bumper cover. It's a small grey cylinder with a green and red wire (I think?) going to it, attached to the inside of the front bumper cover. The sensor is a variable resistor that changes values based on temperature and most who want to continue getting auto-stop below freezing will replace the sensor with a fixed resistor. So, you just need to find a resistance value that equates to a temperature above freezing. I want to say 3.3k or lower will get you auto-stop - that's something like 50F? HOWEVER the climate control also uses this value to calculate how to mix the air, so you'll get some funky results when it's super cold, like nothing but cold air from your vents until you spin it to 90.

[mpg_numbers_guy]

Thanks! I removed my modified air intake and got better fuel economy, confirming that my "warm" air intake was actually a cold air intake. Didn't notice a power change, just a fuel economy drop from it. Makes me hopeful of a fuel economy increase when I get an actual warm air intake installed.

I LOVE driving without the battery so much more than with the battery. Fuel economy is almost the same without the battery as with the battery (just slightly worse/longer acceleration) and I don't have to worry about a battery. 59.5 MPG over a 5.5 mile trip on a cold engine, and 67.6 MPG on the way back after sitting for half an hour. Warming up is key to economy - I may run a full grille block for those short trips, and remove it for longer trips. Breaking over 70 MPG is easy on longer trips. Haven't had a trip long enough to break over 75 MPG, although I know it easily could. Right now, as is, I suspect my peak fuel economy for a trip is 79 MPG - and I haven't experienced the good-MPG-some-days-bad-MPG-other-days that people say happens in the Insight. Maybe because 70+ MPG isn't THAT good in an Insight anyway.

Sent Scott a message on his site about the aluminum belly pan.

Civic is pending sale too, and should be sold by Tuesday.

[19bonestock88]

I seen this the other day and thought of you...

SaturnFans.com Forums

He found that the gear spacing on the HCH1 is better than the Insight, but as we all know the final drive is shorter... nonetheless it made his gas only Insight a little easier to live with... just a thought

[mpg_numbers_guy]

IMA will still work (hopefully) once I replace the ground straps. The plan is to run the clutch switch most the time but keep Autostop. I haven't had any trouble with the Insight's gearing as gas only. The transmission swap seems unnecessary, at least to me, unless one isn't a hypermiler, which in that case I'm not sure why one would own a Gen 1 Insight anyway.

What about a HCH1 transmission or final drive in your Saturn? Isn't the Saturn geared shorter than ideal?

[19bonestock88]

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

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