David's 1996 Civic LX EV

[TheSGC]

Ok, so I might as well start my own EV thread! I have a 1996 Civic LX that I converted to an EV this past year.

Website: Civic Electric Car Conversion

And some specs:
1996 Honda Civic LX
4 Speed Automatic Transmission
ADC K99-4007 6.7" Motor
96 Volts
Eight Walmart Everstart MAXX29 12 volt 125 Ah, 210 minute reserve
Kelly KDH09401 96 Volt 400 AMP controller
PakTrakr battery monitor, gauge

The EV is legal, past inspection this month, but it is not complete. I still have to finish building an insulated battery box, install a blower cooler for the motor and completely rebuild the front compartment. I need a stronger motor mount, splash shield and a solid control tray.

I don't have any decent EV-in-action videos yet, but hopefully they will happen soon.

[Daox]

Very nice build. I was browsing your blog the other day. Will probably continue reading it today.

Have you calculated the losses from using the automatic transmission vs a manual?

[TheSGC]

Originally Posted by Daox

Very nice build. I was browsing your blog the other day. Will probably continue reading it today.

Have you calculated the losses from using the automatic transmission vs a manual?

Yes I did. Assuming a manual transmission is 91% efficient, I found my Automatic Transmission to be 87% efficient. And if I manage to override the Locking Torque Converter to activate in 2nd gear, it would be 89% efficient.

I am working on a way to adjust the shift points on the transmission. Right now I have been placing the car in Drive and when it hits 2nd gear, I shift to D2 and I stay there from 11 to 40 MPH. I am working on changing the shift points from 1700 RPMs to 4500 RPMs.

[Intrigued]

AWRIGHT!!!

Good to see the thread started, SGC! Thanks for adding to the knowledge we are all trying to glean from each other.

I went over to your website, too. I've been there at some time in the past: I think when Ben was trying to come up with a vacuum pump for his car. I remember seeing some of the older stuff.

All of this is great to know, since (not a dream) some day I will be doing a car of my own.

[Christ]

If you want to change the shift points in your Honda-matic (yeah, it's stupid, I know) transmission, you can just shift it manually. It won't hurt the transmission at all, especially now that you're effectively putting less power to the transmission than the original motor was.

You can also play with the transmission itself to create manual valve body, if you wanted to. Also, you can change the stall speed of the torque convertor, but that will affect your TC lockup as well. *You won't have it anymore*.

I'm not sure if you can modify the signals to or from the TCU to change the actual shift points of the transmission, but you can usually just change the sizing of the oil passages in the valve body so that the fluid doesn't build as much pressure as fast, which means that it won't shift at the same RPM. (Shifting is normally controlled by fluid pressure.)

[PaleMelanesian]

How did you handle all the extra weight? Did you put any heavier springs in the rear? I've found it doesn't take much weight to get the back end sagging - it's built to be a light car.

[TheSGC]

Originally Posted by Christ

If you want to change the shift points in your Honda-matic (yeah, it's stupid, I know) transmission, you can just shift it manually. It won't hurt the transmission at all, especially now that you're effectively putting less power to the transmission than the original motor was.

You can also play with the transmission itself to create manual valve body, if you wanted to. Also, you can change the stall speed of the torque convertor, but that will affect your TC lockup as well. *You won't have it anymore*.

I'm not sure if you can modify the signals to or from the TCU to change the actual shift points of the transmission, but you can usually just change the sizing of the oil passages in the valve body so that the fluid doesn't build as much pressure as fast, which means that it won't shift at the same RPM. (Shifting is normally controlled by fluid pressure.)

Any kind of mechanical shifting (besides the shifter, which I do, force it into 2nd) is out of the question because of the electronically controlled tranny. I thought of changing valves, but after going through the factory guide, that was out of the question.

BUT I do have a plan. At this point the only sensor the PCM gets is the VSS, so my idea is to skew it. I have a PIC processor that I am programming to read the VSS and then spit half the pulses (or less) to the PCM and it will think I am driving slower than I really am. Then it will stay in gear longer, and I won't have to do anything but shove it into D and drive off.

[TheSGC]

Originally Posted by PaleMelanesian

How did you handle all the extra weight? Did you put any heavier springs in the rear? I've found it doesn't take much weight to get the back end sagging - it's built to be a light car.

I am looking for beefier rear springs, but haven't found any yet that won't break the bank. I have 520 lbs of batteries in the trunk, and yes it is low. All the springs I have found are for lowering the suspension, it's got to be an EV conspiracy.

[Christ]

Get a set of adjustable coilovers from eBay. The springs are generic cuts, rated just past the OEM rating for spring rates, and you can adjust them up so that even though they're shorter, they will be at standard ride height. They're also less than $60 and the fronts will fit the rears if they wear out.

[Intrigued]

Originally Posted by TheSGC

I have a PIC processor that I am programming to read the VSS and then spit half the pulses (or less) to the PCM and it will think I am driving slower than I really am. Then it will stay in gear longer, and I won't have to do anything but shove it into D and drive off.

Ooooh, I like it! When you get it figured out, give us a hint, so that the slushbox guys can be cool too!

Do the OEM signals split for the speedomoter, or will you have to re-adjust the signal somehow to know how fast you're going???