apart from the starter, why does a sierra need a battery to run. ive always wondered.

im assuming something to do with the distributer. I didn't think they had a computer and it was all mechanically run.

Many racing cars don't have a battery,
hence push start vehicles,
and rolling starts.

Are you sure about that Chris? Do you have any examples?

Rolling starts were used to save driveline components from the shock of a standing start.

Push starting has more to do with no starter motor IMHO.

Steve.

Some Sprint car, mini modified and other cicle track classes dont allow electrical systems http://www.centuryperformance.com/mallo ... pg-76.html

http://en.wikipedia.org/wiki/Sprint_car_racing

The World of Outlaws (WoO) is a division of winged sprint cars that run all over the United States and have a few events in Canada. The cars have 15-inch (380 mm) wide right rear tire and a 410 cubic inch engine with mechanical fuel injection. These sprint cars have no battery or a starter in them, necessitating a push start by a quad or truck. They also do not have flywheels, clutches or transmissions, but the direct drive system can be engaged or disengaged from the cockpit. This is done both for weight reasons and tradition

Alternators need a field current to get started.

Mechanical injection cool but what about the ignition side of things?

Magneto, same as a lawn mower

It depends on the alternator - some are self exiciting, single wire, and most of those which require a field connection will also "self excite" due to residual magnetism.

on a old carb engine you should be able to run it without a battery

ever had a stuffed battery? you can dive around for as long as you want.
but if you stop... you best get out and push

and on the same note. if you have ever had a stuffed alternator. the electric fuel pump stopping is what will get ya. unless you have a manual fuel pump.

think of lawn mowers and dirt bikes.

SO i reckon that as long as you dont demagnetise/depolarise it with a AC electromagnet ,,, and that you can push start or hand crank it.. then no, no need for a battery is my vote.

Every car, and Zook i have owned, would stop running as soon as the battery was disconnected, my first 1L Sierra did it, my 1.3L Sierra did it, my 89 Vit did it.... havnt been game to try it on the GV, to much electronicals that might get damaged... but if the battery is still connected, even if it is not holding a charge, will still run...

some1's going to have to try it, and video it, to settle this.

OR.. does ne1 know the phone number for mythbusters?

ive disconnected the battery while its running before too, we know cars run without a battery but what we want to know is will it START without a battery?