Dreaming...lean burn manual taller transmission Civic sedan...or get an Insight

[Ecky]

Originally Posted by mpg_numbers_guy

That's good to know. Maybe I won't remove the IMA after all. I'm assuming a degraded IMA still charges the 12V enough so I wouldn't have to wire up that DC-DC thingy to avoid the 12V only charging between 1400 and 3500 RPMs?

A degraded IMA still charges the 12v system until it's at its very end. With it disconnected, you still get some charging at idle, but the lights are dimmer. Charging cutoff is at 4k, but it immediately comes back on below 4k.

Originally Posted by mpg_numbers_guy

Speaking of the buttons, if the buttons are broken they can be replaced with 3D printed ones from IC, right?

The big FCD button never breaks. The smaller ones on the cluster get hard to push on some cars. The fix isn't 3d printed, but replacements from Mouser cost less than $5. There's also a service on IC to replace all of them for $20 if you don't want to do the soldering yourself.

[Ecky]

As promised, I recorded a video of driving my Insight. Video was driving home from getting some groceries. Speed limit was ~35 most of the trip, traffic was low and I caught all of the lights. I live by the lake, which is around 200ft lower elevation, so the mileage you're seeing is partly from going downhill during the last ~1.5 miles. Outside temp was also 53F which has a small but measureable negative impact on economy.

http://www.youtube.com/watch?v=9w-Oa...ature=youtu.be

It occurs to me it would be a much better video if I narrated, might do another with that, but you'll see soon enough if you get one.

[mpg_numbers_guy]

Originally Posted by Ecky

A degraded IMA still charges the 12v system until it's at its very end. With it disconnected, you still get some charging at idle, but the lights are dimmer. Charging cutoff is at 4k, but it immediately comes back on below 4k.

So unless the battery is actually dead it's better to leave it hooked up?

Originally Posted by Ecky

The big FCD button never breaks. The smaller ones on the cluster get hard to push on some cars. The fix isn't 3d printed, but replacements from Mouser cost less than $5. There's also a service on IC to replace all of them for $20 if you don't want to do the soldering yourself.

Awesome, I'll have to look into that in case the Insight I end up getting has bad buttons.

Originally Posted by Ecky

As promised, I recorded a video of driving my Insight. Video was driving home from getting some groceries. Speed limit was ~35 most of the trip, traffic was low and I caught all of the lights. I live by the lake, which is around 200ft lower elevation, so the mileage you're seeing is partly from going downhill during the last ~1.5 miles. Outside temp was also 53F which has a small but measureable negative impact on economy.

It occurs to me it would be a much better video if I narrated, might do another with that, but you'll see soon enough if you get one.

Oh. My. Word. That is just crazy amazing. Thank you so much for sharing!!

Out of curiosity, when climbing a slight grade, is it better to "floor" it in 5th gear or downshift into 4th and maintain lean burn?


I return home for winter break the 2nd week of December. Then I drive my Civic doing pizza delivery...in winter weather...where despite mods breaking over 40 MPG will be a challenge...until 2nd week of January when I sell it and return to college. Then when I return home for spring break I'll be on the hunt for an Insight. Oh why does it have to be this long of a wait!!

[hayden55]

You know it honestly has gotten to such a great point to start upgrading hybrid batteries that I'm surprised people are still disabling the ima batteries on these cars.
Does anybody know what depth of discharge the OEM battery is designed to stay within on the bms? From the specs on Honda's website its 144V 6.5Ah battery. That's really only 80 18650 battery cells and you could do a couple packs of 40 cells to get whatever Ah pack you want. Similar to what Tesla does with 3350mAh 18650 cells. The cool part is that 80 cells weighs less than 8 pounds for the cells themselves and you could configure this pack to have so many cycles of capacity depeneding on dod that it would pretty last indefinitely (if configured to stay between 30-70% discharge the panasonic cells in the model 3 have a 40,000 cycle life). I don't know much about the oem pack. Does it have a battery fan, battery warmer?

[Ecky]

Originally Posted by hayden55

You know it honestly has gotten to such a great point to start upgrading hybrid batteries that I'm surprised people are still disabling the ima batteries on these cars.
Does anybody know what depth of discharge the OEM battery is designed to stay within on the bms? From the specs on Honda's website its 144V 6.5Ah battery. That's really only 80 18650 battery cells and you could do a couple packs of 40 cells to get whatever Ah pack you want. Similar to what Tesla does with 3350mAh 18650 cells. The cool part is that 80 cells weighs less than 8 pounds for the cells themselves and you could configure this pack to have so many cycles of capacity depeneding on dod that it would pretty last indefinitely (if configured to stay between 30-70% discharge the panasonic cells in the model 3 have a 40,000 cycle life). I don't know much about the oem pack. Does it have a battery fan, battery warmer?

A lot of reasons. The computers don’t like when you change battery chemistries. The BMS freaks out. And, normal off the shelf 18650’s don’t handle 100 amp charging rates very well. You end up needing a battery with 5x the capacity with high current rated cells so they don’t pop when you hit the brakes.

OEM pack doesn’t have a warmer, it just overcharges the batteries until they warm up, which would destroy lithium cells. There’s a fan, at least.

People are working on it, but it’s not remotely simple.

[Ecky]

Originally Posted by mpg_numbers_guy

So unless the battery is actually dead it's better to leave it hooked up?

I'd say that's usually the case. When it gets very near the absolute end, it can start causing the car to regenerate a lot more to keep the battery up, which won't hold a charge anymore, but often it still saves fuel at this point just from auto-stop.

Originally Posted by mpg_numbers_guy

Oh. My. Word. That is just crazy amazing. Thank you so much for sharing!!

Out of curiosity, when climbing a slight grade, is it better to "floor" it in 5th gear or downshift into 4th and maintain lean burn?

You'll find contention about this. I don't think there are any BSFC charts for lean burn. There are some who believe BSFC is better, period, when in lean burn, and will do things like run 3rd gear in learn burn rather than 5th gear at times. There are others who suspect lean burn just improves BSFC at part throttle, but that ultimately it's better to run the engine at lower RPM when you can - after all, vacuum is the same, but friction is lower and all of the accessories are spinning lower so you have fewer parasitic losses.

I personally know of one person who averages 130+ mpg without lean burn at all, FWIW, but he's crazy. My testing has shown that it was worth at least 10mpg on my old commute, but I lean toward the 2nd camp.

Originally Posted by mpg_numbers_guy

I return home for winter break the 2nd week of December. Then I drive my Civic doing pizza delivery...in winter weather...where despite mods breaking over 40 MPG will be a challenge...until 2nd week of January when I sell it and return to college. Then when I return home for spring break I'll be on the hunt for an Insight. Oh why does it have to be this long of a wait!!

Good luck and happy hunting! It's important to remember that even as reliable as these are, they're still nearing 20 years old. There may be a lot of small "tune-up" items you'll want to do to maximize economy, even on a very clean one. Things like greasing the brake calipers (reduces brake drag), cleaning the EGR passages, coolant, fresh transmission fluid, the sort of stuff that really should be done on any car but is neglected on most.

[mpg_numbers_guy]

Originally Posted by Ecky

I'd say that's usually the case. When it gets very near the absolute end, it can start causing the car to regenerate a lot more to keep the battery up, which won't hold a charge anymore, but often it still saves fuel at this point just from auto-stop.

Couldn't you install a switch to disable the hybrid system to prevent forced regen while driving, and enable it for when you wanted to autostop?

Originally Posted by Ecky

You'll find contention about this. I don't think there are any BSFC charts for lean burn. There are some who believe BSFC is better, period, when in lean burn, and will do things like run 3rd gear in learn burn rather than 5th gear at times. There are others who suspect lean burn just improves BSFC at part throttle, but that ultimately it's better to run the engine at lower RPM when you can - after all, vacuum is the same, but friction is lower and all of the accessories are spinning lower so you have fewer parasitic losses.

Does lean burn reduce HP output? I was thinking in regards to climbing a hill, because if downshifting to 4th or even 3rd but maintaining speed and lean burn would be more efficient than lugging it up in 5th and having to re-accelerate at the top of the hill.

Originally Posted by Ecky

I personally know of one person who averages 130+ mpg without lean burn at all, FWIW, but he's crazy. My testing has shown that it was worth at least 10mpg on my old commute, but I lean toward the 2nd camp.

Are you talking about the guy from IC who runs 120 PSI in his tires?

Originally Posted by Ecky

Good luck and happy hunting! It's important to remember that even as reliable as these are, they're still nearing 20 years old. There may be a lot of small "tune-up" items you'll want to do to maximize economy, even on a very clean one. Things like greasing the brake calipers (reduces brake drag), cleaning the EGR passages, coolant, fresh transmission fluid, the sort of stuff that really should be done on any car but is neglected on most.

Thank you, and yes, definitely keeping that in mind. I see it as a learning opportunity whereby I can have some things repaired, and repair other things myself. Obviously I won't be buying an Insight where the repairs make it not worthwhile; my goal is to come out as close to $1000 ahead on this after selling my Civic, repairs and up front maintenance included. Battery quality isn't really important to me so I should be able to get one fairly cheap, based on the prices I'm seeing.

My dad works at a Honda dealership, so what we did when I bought my current car was when we had the timing belt replaced (original one was on at 150K miles) they flushed out and changed all the fluids. Thanks to you though I now have a list specific to Insights of what to be looking out for, which will be extremely helpful.

I can't wait to get this done and show it off to my coworkers. They already laughed at my car barely having over 100 HP and next year I'll be upgrading to something like 60-70 HP.

[Ecky]

Originally Posted by mpg_numbers_guy

Couldn't you install a switch to disable the hybrid system to prevent forced regen while driving, and enable it for when you wanted to autostop?

All of the car's computers need to reboot, and then you need to clear the CEL. It wouldn't be a simple switch, but rather a process that takes several minutes and is multi-step. Anyhow, once the battery is that bad, the regen is necessary to have the energy for auto-stop. We're talking the final weeks of a battery's life before it does nothing, not months or years.

Originally Posted by mpg_numbers_guy

Does lean burn reduce HP output? I was thinking in regards to climbing a hill, because if downshifting to 4th or even 3rd but maintaining speed and lean burn would be more efficient than lugging it up in 5th and having to re-accelerate at the top of the hill.

Yeah, if you lean out by 33% (14:1 to 21:1), you also lose 33% of your power. You're burning 33% less fuel, after all. It's not free fuel saved. It's only useful if you are only running part throttle in a given gear, leaning out let's you run a wider throttle opening and save a small amount by making less vacuum. It might also affect BSFC, but measuring that would be very difficult.

Lean burn would be nearly pointless on a Prius, for instance, because it has effectively infinite gearing. You just slow the engine down more, or toggle it on and off.

There are a few other subtleties where it's useful, like allowing an engine to actually run at a higher rpm at WOT and make the same power - sometimes this is useful, but it's not really low hanging fruit.

Originally Posted by mpg_numbers_guy

Are you talking about the guy from IC who runs 120 PSI in his tires?

Yep, he had no lean burn for a long time.

[mpg_numbers_guy]

Originally Posted by Ecky

All of the car's computers need to reboot, and then you need to clear the CEL. It wouldn't be a simple switch, but rather a process that takes several minutes and is multi-step. Anyhow, once the battery is that bad, the regen is necessary to have the energy for auto-stop. We're talking the final weeks of a battery's life before it does nothing, not months or years.

But didn't you used to have a calpod switch that controlled the IMA being on and off? Or maybe that was Natalya.

Originally Posted by Ecky

Yeah, if you lean out by 33% (14:1 to 21:1), you also lose 33% of your power. You're burning 33% less fuel, after all. It's not free fuel saved. It's only useful if you are only running part throttle in a given gear, leaning out let's you run a wider throttle opening and save a small amount by making less vacuum. It might also affect BSFC, but measuring that would be very difficult.

Lean burn would be nearly pointless on a Prius, for instance, because it has effectively infinite gearing. You just slow the engine down more, or toggle it on and off.

There are a few other subtleties where it's useful, like allowing an engine to actually run at a higher rpm at WOT and make the same power - sometimes this is useful, but it's not really low hanging fruit.

Ah, makes sense about less power.

About the Prius comparison though, are you saying that the Insight's ECU controls how lean it runs based on engine load?

Originally Posted by Ecky

Yep, he had no lean burn for a long time.

Not going to run 120 PSI in my tires for that though...60 PSI is good enough.

[Ecky]

Originally Posted by mpg_numbers_guy

But didn't you used to have a calpod switch that controlled the IMA being on and off? Or maybe that was Natalya.

Yeah but that one is much simpler. The IMA system doesn't assist or regen when the clutch is pressed, so you just add a clutch switch toggle. It's not physically turning anything off.

Originally Posted by mpg_numbers_guy

Ah, makes sense about less power.

About the Prius comparison though, are you saying that the Insight's ECU controls how lean it runs based on engine load?

It would be ideal if it did, but that would probably be a tuning nightmare. There's just a lean and a normal map, and it switches between the two.