3 Cyl Metro Pull Start?

[seifrob]

does it have injection or carburator? when I was a kid, my dad adapted his Skoda 100 for hand cranking, but it was old-fashioned carburated engine with spark distributor.
As far as I remember, it also kicked hard so he started the car by hand only when batttery was too weak to power the starter.

Beside that, hand cranking mod shoul be relatively easy. you just need socket (preferably ratchet type) bolted to a crankshaft, handle with two pins at the end and thats all...

[markweatherill]

Originally Posted by Shaneajanderson

eliminate the constant draw of a battery that can't be charged further, yet the alternator is trying to do so.

Once the battery's voltage is up to 'fully charged' the alternator will stop 'trying' to charge it

[Shaneajanderson]

Originally Posted by markweatherill

Once the battery's voltage is up to 'fully charged' the alternator will stop 'trying' to charge it

The problem is an auto battery only accepts ~12.5 volts, while the alternator is putting out 14.5 assuming it's healthy. The alternator is constantly working to make up this 2V difference, and it causes a significant load on the engine while doing so. People have seen I believe as much as 10% fuel economy increase by eliminating this load. That translates to another 4-5 MPG in my geo if it holds true.

[Kzelisko]

The battery isn't what causes the majority of the alternator load, it's everything else in the car. The alternator will run at 14volts with or without a battery connected, so the load will still be there running all the various electronics in the car.

Another important note, I strongly suggest not driving any car without some manner of battery or capacitor or something to smooth out voltage, the voltage will jump around enough to damage electronics without one.

[redpoint5]

The lead acid battery is extremely inefficient at accepting a charge when it's nearly full; perhaps as low as 50% or less. The thing is though, wasting 50% of almost nothing is still almost nothing.

I don't even think 1% gain in fuel economy is possible by replacing the lead acid battery.

[Shaneajanderson]

Originally Posted by redpoint5

The lead acid battery is extremely inefficient at accepting a charge when it's nearly full; perhaps as low as 50% or less. The thing is though, wasting 50% of almost nothing is still almost nothing.

I don't even think 1% gain in fuel economy is possible by replacing the lead acid battery.

Interesting. I thought people had seen good gains by doing this previously? Or do they ditch the alternator and just bank on their battery lasting long enough to get home?

[redpoint5]

The alternator is very inefficient, and ditching it has shown gains of around 5% depending on how efficient the vehicle is in the first place and the electrical demands. That requires more battery capacity and a means of charging from the grid.

I think there are gains to be had by replacing the lead acid battery with another chemistry or perhaps a supercap, but they would be very small and likely not measurable. One of my projects is to measure the difference in efficiency between a lead acid and lithium ion battery someday by discharging it some measured amount, and then measuring how much energy is required to charge it back to "full".

[Shaneajanderson]

Originally Posted by redpoint5

The alternator is very inefficient, and ditching it has shown gains of around 5% depending on how efficient the vehicle is in the first place and the electrical demands. That requires more battery capacity and a means of charging from the grid.

I think there are gains to be had by replacing the lead acid battery with another chemistry or perhaps a supercap, but they would be very small and likely not measurable. One of my projects is to measure the difference in efficiency between a lead acid and lithium ion battery someday by discharging it some measured amount, and then measuring how much energy is required to charge it back to "full".

Ok. This project will probably never get done on my car then. The old Metro is pretty fuel efficient as is, and a new O2 sensor will do far more than the maybe 1% you're predicting here.

Obviously my reading comprehension needs some help.