# [EVDL] Improving the Efficiency of a Geo Metro EV Conversion



## EVDL List (Jul 27, 2007)

My Geo 1994 Geo Metro EV was originally converted by BAT Intl. It retains the stock 3-speed automatic transmission bolted to an 8" ADC drive motor. Some slippage upon acceleration from dead stop would indicate the torque converter remains. I simply apply throttle carefully, shift the transmission manually as needed, and enjoy doing that.

I'd like to increase the operating efficiency though. What about removing the torque converter and directly coupling the motor output shaft to the transmission input shaft? I'm told its doable provided a suitable coupling is available, or one could be machined if necessary. 
Is it a practical approach to achieving greater efficiency and what are the pluses and minuses? 

Mark 















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## EVDL List (Jul 27, 2007)

Hello Mark,

Yes, this can be done. See the automatic transmission coupler at:

http://go-ev.net/pics/028.html

Click the images no. 29 and up to see this unit.

This unit is for a GM TH-400 transmission from tci.com . You will notice 
that this tube slides over the transmission input shaft just like a torque 
converter does.

The other end is a spline shaft that is allow to slide back and forth by 1/8 
to 3/16 of a inch. This is how much a flex plate would flex when using with 
a torque converter.

The spline flange coupler is furnish with the drive tube and has snap rings 
on it to adjust the amount of back and forth movement.

This company may or may not have this unit for your transmission, so some 
guys will take a torque converter and cut it open and weld it solid to the 
end plate that is then bolted to a flex plate which is then bolted to the 
motor coupler and you will maintain the amount of flex is needed.

You have to weld shut the end of the tube going to the back torque converter 
flange, to contain the transmission in the transmission.

If you use this type of method of hacking up a torque converter housing 
which will reduce a lot of weight, you will have to have it balance.

Another way to do this, is use the old torque converter tube and cut off the 
torque converter fins and extended the correct distance and weld it on to a 
round plate that the flex plate can bolt to if the end plate of the torque 
converter is too thin to do it this way.

You can use the old torque converter measurements to built the correct 
length tube.

Roland


----- Original Message ----- 
From: "Mark Freidberg" <[email protected]>
To: <[email protected]>
Sent: Thursday, February 26, 2009 3:35 PM
Subject: [EVDL] Improving the Efficiency of a Geo Metro EV Conversion


>
> My Geo 1994 Geo Metro EV was originally converted by BAT Intl. It retains 
> the stock 3-speed automatic transmission bolted to an 8" ADC drive motor. 
> Some slippage upon acceleration from dead stop would indicate the torque 
> converter remains. I simply apply throttle carefully, shift the 
> transmission manually as needed, and enjoy doing that.
>
> I'd like to increase the operating efficiency though. What about removing 
> the torque converter and directly coupling the motor output shaft to the 
> transmission input shaft? I'm told its doable provided a suitable coupling 
> is available, or one could be machined if necessary.
> Is it a practical approach to achieving greater efficiency and what are 
> the pluses and minuses?
>
> Mark
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> _______________________________________________
> General EVDL support: http://evdl.org/help/
> Usage guidelines: http://evdl.org/help/index.html#conv
> Archives: http://evdl.org/archive/
> Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev
>
> 

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## EVDL List (Jul 27, 2007)

Why not just buy a manual trans and shift linkage ?

Ray
----- Original Message ----- 
From: "Mark Freidberg" <[email protected]>
To: <[email protected]>
Sent: Thursday, February 26, 2009 6:35 PM
Subject: [EVDL] Improving the Efficiency of a Geo Metro EV Conversion


>
> My Geo 1994 Geo Metro EV was originally converted by BAT Intl. It retains 
> the stock 3-speed automatic transmission bolted to an 8" ADC drive motor. 
> Some slippage upon acceleration from dead stop would indicate the torque 
> converter remains. I simply apply throttle carefully, shift the 
> transmission manually as needed, and enjoy doing that.
>
> I'd like to increase the operating efficiency though. What about removing 
> the torque converter and directly coupling the motor output shaft to the 
> transmission input shaft? I'm told its doable provided a suitable coupling 
> is available, or one could be machined if necessary.
> Is it a practical approach to achieving greater efficiency and what are 
> the pluses and minuses?
>
> Mark
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> _______________________________________________
> General EVDL support: http://evdl.org/help/
> Usage guidelines: http://evdl.org/help/index.html#conv
> Archives: http://evdl.org/archive/
> Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev
>
> 


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## EVDL List (Jul 27, 2007)

> Mark Freidberg wrote:
> 
> > My Geo 1994 Geo Metro EV was originally converted by BAT
> > Intl. It retains the stock 3-speed automatic transmission
> ...


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## EVDL List (Jul 27, 2007)

Hi Roger,

Shifting to '1' and depressing throttle just enough to spin the motor doesn't generate pull against the parking brake. Dashboard digital ammeter reading held steady at 12 amps. Nominal pack voltage is 96v. Geo has been parked in ambient air temperatures in high 30s to 40s F.

Longer term I've noticed that air temps over 70 F result in less slippage then colder air masses. So does driving a few miles in colder temps once transmission warms up. In general, '1' has less slippage then '2' or 'D' when accelerating from dead stop (car and motor motionless.

Does that info. help determine what BAT did?


Ray,

I haven't ruled out the option you mentioned although some have remarked about the difficulty of replacing an AT with a MT.


Roland,

The Tci.com link didn't work. What is the company name?



Mark





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## EVDL List (Jul 27, 2007)

I have a drag racing friend who is a very experienced automatic transmission 
modifier and I discussed some options with him about a year ago.

My idea was to eliminate the torque converter and use an electric powered 
aux pump like the ones used for power steering. I would use this pump to 
pressurize the trans when at rest and at very low speeds. Once the tranny's 
internal pump came up to pressure a pressure switch would cut the power to 
the electric pump. Some clever use of one-way valves would be required in 
the plumbing.

The first gear clutch in an auto tranny is normally not designed to be 
engaged while under load. The higher gears use accumulators to slow the 
engagement of the clutches to cushion the shift.

The tranny he suggested didn't use a vacuum modulator to control any 
functions of the tranny, it used a cable hooked to the throttle linkage.

Good luck


----- Original Message ----- 
From: "Mark Freidberg" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Friday, February 27, 2009 3:36 AM
Subject: Re: [EVDL] Improving the Efficiency of a Geo Metro EV Conversion


>
> Hi Roger,
>
> Shifting to '1' and depressing throttle just enough to spin the motor 
> doesn't generate pull against the parking brake. Dashboard digital ammeter 
> reading held steady at 12 amps. Nominal pack voltage is 96v. Geo has been 
> parked in ambient air temperatures in high 30s to 40s F.
>
> Longer term I've noticed that air temps over 70 F result in less slippage 
> then colder air masses. So does driving a few miles in colder temps once 
> transmission warms up. In general, '1' has less slippage then '2' or 'D' 
> when accelerating from dead stop (car and motor motionless.
>
> Does that info. help determine what BAT did?
>
>
> Ray,
>
> I haven't ruled out the option you mentioned although some have remarked 
> about the difficulty of replacing an AT with a MT.
>
>
> Roland,
>
> The Tci.com link didn't work. What is the company name?
>
>
>
> Mark
>
>
>
>
>
> _______________________________________________
> General EVDL support: http://evdl.org/help/
> Usage guidelines: http://evdl.org/help/index.html#conv
> Archives: http://evdl.org/archive/
> Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev
>
> 


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## EVDL List (Jul 27, 2007)

Hello Mark and Ray,

The TCI web site is www.tci.com or you can get to it by just typing 
tci.com. T in TCI is in lower syntax.

I use a standard transmission pump from jegs.com that is normally use in the 
cooling lines and is rated for 50 psi. I went to my transmission shop, to 
see which side of the pump cover is the suction side of the pump. Pick up 
some pump cover gaskets and remove the pump cover and drill and tap it with 
a 1/4 inch pipe tap.

Install a Aeroquip 90 degree fitting and connected a Aeroquip hose which is 
rated for 600 psi. The oil pressure in my transmission on the high side is 
175 to 200 psi when the motor is turning it at 325 rpm.

On this TH-400, you cannot keep the oil pressure that high for too long or 
you will blow the pump seals. In drag racing, they keep that pressure or 
even higher for the run, and than lower the pressure by turning off the 
external pump. Normally they may replace the seals and gaskets after each 
run.

The low side is about 50 psi which can start to move the vehicle, which I am 
at about 1 mph at is about 250 rpm. This is with a overall gear ratio over 
20:1 in reversed and still be over 1 mph in 1st gear. I normally back out 
of the garage faster then that.

This line from the pump face goes through a grommet hole in the bell housing 
and makes a 90 degree into a HD brass electric value that is normally use on 
the A/C systems on a semi which I pick up from the Freightliner parts 
counter.

I install the electric value with the flow arrow point to the transmission 
internal transmission pump so now it will act like a check value and prevent 
the high pressure oil from the internal pump to back flow through these 
lines.

>From this electric value it then goes into the standard transmission pump, 
then to a in line oil filter from jegs.com that is good for over 300 psi. 
Then from the oil filter it pulls the oil from a deep cast aluminum 
transmission oil pan.

This oil pan has a boss that is about 3/8 inch thick for a pipe tap. The 
entry point is just above the transmission oil filter. The side of this 
transmission has a tap boss for a electric oil pressure sender to a gage on 
the dash.

I just use a switch on the dash, console and just behind the steering wheel 
to turn control the external pump. I thought I could use a tap off my 
electric steering pump from Can.EV or is it EV.Can. But the pressure is too 
high at 777 psi. It would have to be regulated and the power steer fluid 
would have to be isolated from the transmission fluid.

I'am using the standard vacuum modulator that plugs into the transmission. 
When the vacuum is high 15 to 22 in.hg. the transmission oil pressure 
becomes lower and when the vacuum is low from 0 to 15 in.hg. the pump 
pressure is higher.

Normally a engine vacuum will drop under load and acceleration which 
increases the transmission oil pressure and decreases it when the vacuum 
raises. To control this operation with a EV or in a diesel engine, I use a 
GMC diesel modulator control that is connected to the the accelerator 
linkage. There is also some aftermarket units that are computer electrical 
control, if you have the latter transmission for it.

I do not have this unit that fits the GE-11 motor in the EV at this time. 
The GE-11 is in full maintenance overhaul while the Warp 9 motor with a 
manual nightmare transmission is in the EV.

To replace this transmission with a glass smooth bevel gears and closer 
ratios from jegs.com will cost 3 times more than the automatic. So I will 
try the automatic and see what's happens.

Roland


----- Original Message ----- 
From: "Ray Brooks" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Friday, February 27, 2009 5:39 AM
Subject: Re: [EVDL] Improving the Efficiency of a Geo Metro EV Conversion


> I have a drag racing friend who is a very experienced automatic 
> transmission
> modifier and I discussed some options with him about a year ago.
>
> My idea was to eliminate the torque converter and use an electric powered
> aux pump like the ones used for power steering. I would use this pump to
> pressurize the trans when at rest and at very low speeds. Once the 
> tranny's
> internal pump came up to pressure a pressure switch would cut the power to
> the electric pump. Some clever use of one-way valves would be required in
> the plumbing.
>
> The first gear clutch in an auto tranny is normally not designed to be
> engaged while under load. The higher gears use accumulators to slow the
> engagement of the clutches to cushion the shift.
>
> The tranny he suggested didn't use a vacuum modulator to control any
> functions of the tranny, it used a cable hooked to the throttle linkage.
>
> Good luck
>
>
> ----- Original Message ----- 
> From: "Mark Freidberg" <[email protected]>
> To: "Electric Vehicle Discussion List" <[email protected]>
> Sent: Friday, February 27, 2009 3:36 AM
> Subject: Re: [EVDL] Improving the Efficiency of a Geo Metro EV Conversion
>
>
> >
> > Hi Roger,
> >
> > Shifting to '1' and depressing throttle just enough to spin the motor
> > doesn't generate pull against the parking brake. Dashboard digital 
> > ammeter
> > reading held steady at 12 amps. Nominal pack voltage is 96v. Geo has 
> > been
> > parked in ambient air temperatures in high 30s to 40s F.
> >
> > Longer term I've noticed that air temps over 70 F result in less 
> > slippage
> > then colder air masses. So does driving a few miles in colder temps once
> > transmission warms up. In general, '1' has less slippage then '2' or 'D'
> > when accelerating from dead stop (car and motor motionless.
> >
> > Does that info. help determine what BAT did?
> >
> >
> > Ray,
> >
> > I haven't ruled out the option you mentioned although some have remarked
> > about the difficulty of replacing an AT with a MT.
> >
> >
> > Roland,
> >
> > The Tci.com link didn't work. What is the company name?
> >
> >
> >
> > Mark


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## EVDL List (Jul 27, 2007)

> I have a drag racing friend who is a very experienced automatic 
> transmission modifier and I discussed some options with him about a 
> year ago.
>
> My idea was to eliminate the torque converter and use an electric 
> powered aux pump like the ones used for power steering. I would use 
> this pump to pressurize the trans when at rest and at very low speeds. 
> Once the tranny's internal pump came up to pressure a pressure switch 
> would cut the power to the electric pump. Some clever use of one-way 
> valves would be required in the plumbing.
>
> The first gear clutch in an auto tranny is normally not designed to be 
> engaged while under load. The higher gears use accumulators to slow 
> the engagement of the clutches to cushion the shift.
>
> The tranny he suggested didn't use a vacuum modulator to control any 
> functions of the tranny, it used a cable hooked to the throttle linkage.
>
> Good luck

Here is the question I would ask him. I always wanted to know if this 
was possible.
What about tossing the tranny and just using a torque converter.
I guess we'd still need a pump and probably a cooler But don't they 
start at about 4:1 and approach 1:1 just before lockup(if they are locking)


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## EVDL List (Jul 27, 2007)

A torque converter is a heat generating device that just happens to also 
work as a coupling between an engine and a transmission 

In addition to the torque convertor, you will need a pump to circulate and 
pressurize the trans fluid; a housing for the pump to align it with the 
motor and also to house the input / output shaft and this housing will also 
need to allow you to hook the output shaft to the propellor shaft AND this 
housing will need to keep all the fluid from squirting out everywhere AND 
AND this will be a custom casting or else whittle it out of a big billet [ 
either is big dollars]; you will need a cooler; a reservoir for the fluid; 
hoses; etc.

What we really need is a lightweight 2 speed rearend.

Now here is my idea for motor coupling: One way roller clutch or sprag so 
that when you let off the throttle the motor quits turning but the tranny 
keeps freewheeling. Then when you reapply the throttle the roller clutch 
locks back up and the power flows as normal.

Ray
----- Original Message ----- 
From: "Jeff Shanab" <[email protected]>
To: <[email protected]>
Sent: Friday, February 27, 2009 10:29 PM
Subject: Re: [EVDL] Improving the Efficiency of a Geo Metro EV Conversion


>> I have a drag racing friend who is a very experienced automatic
>> transmission modifier and I discussed some options with him about a
>> year ago.
>>
>> My idea was to eliminate the torque converter and use an electric
>> powered aux pump like the ones used for power steering. I would use
>> this pump to pressurize the trans when at rest and at very low speeds.
>> Once the tranny's internal pump came up to pressure a pressure switch
>> would cut the power to the electric pump. Some clever use of one-way
>> valves would be required in the plumbing.
>>
>> The first gear clutch in an auto tranny is normally not designed to be
>> engaged while under load. The higher gears use accumulators to slow
>> the engagement of the clutches to cushion the shift.
>>
>> The tranny he suggested didn't use a vacuum modulator to control any
>> functions of the tranny, it used a cable hooked to the throttle linkage.
>>
>> Good luck
>
> Here is the question I would ask him. I always wanted to know if this
> was possible.
> What about tossing the tranny and just using a torque converter.
> I guess we'd still need a pump and probably a cooler But don't they
> start at about 4:1 and approach 1:1 just before lockup(if they are 
> locking)
>
>
> _______________________________________________
> General EVDL support: http://evdl.org/help/
> Usage guidelines: http://evdl.org/help/index.html#conv
> Archives: http://evdl.org/archive/
> Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev
>
> 


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## EVDL List (Jul 27, 2007)

> Jeff Shanab wrote:
> >> I have a drag racing friend who is a very experienced automatic
> >> transmission modifier and I discussed some options with him about a
> >> year ago.
> ...


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## EVDL List (Jul 27, 2007)

> Mark Freidberg wrote:
> 
> > Hi Roger,
> >
> ...


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