elimination of alternator for race car

[Guest egmar]

I would like to try to save some weight and on my 240z race car and eliminate the alternator. the ignition and fuel pump will easily run on a fully charged battery. anybody out there having done this before? I will try to find the right size belt to run the waterpump without tensioner.

egmar

[Z-Gad]

I have seen racers pull the alternator belt on old muscle cars to eliminate one drive belt at the drag strip and such. You could run an electric pump and then eliminate any belt driven accessories. There is one made for the L-motor now, thanks to Jeff P

[dr_hunt]

You won't save anything and you won't run any faster without it unless you run a magneto. Bottom line is that the coil takes the primary voltage and multiplies it by the number of turns in the coil. If you have fuel pump and distributor drawing amps, then the voltage across the battery drops and so does the coil output and thus the fire to the plugs.

 

Simple example math, 12 volts primary voltage, generates 50,000 volts at the plug (HP coil). That translates to a factor of 4166, increase. So, say your running without an alternator and your voltage across the battery drops to say 11 volts, that means that you now have 45,833 volts at the plug instead of 50,000. But in reality when you run an alternator you have about 14 volts in the system and without one you will never have more than 12.5 volts and that is with a fully charged battery.

 

So if your running a magneto, fine, if not, then keep the alternator, you'll be faster and more consistent.

[Guest egmar]

thank you very much for your quick reply. I have already tried and tested to run without the alternator charging the system. I manged to run the same lap times. It seems like my little MSD box runs happily with the 13lbs battery firing it. Eliminating the alternator seems to have 2 advantages. One is having less drag and the other is reducing weight. The drag factor and the resulting loss in power was explained to me by a friend, who had his touring car rigged, so that the alternator would only charge under braking. he said that a gain of 1.5 hp could be achieved. I am only involved in SCCA club racing, but I am having fun listening to the professionals.

egmar