What do I need to do to run without it? Also will I gain that much by getting rid of it?
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What do I need to do to run without it? Also will I gain that much by getting rid of it?
If you wish to eliminate your alternator, you can buy a relatively cheap 12VDC-to-16VDC converter to power your ignition system. Your gauges & tach may still be run directly off the 12VDC battery. Then simply charge the battery between every practice session, heat races, and before the Main event. Will you gain much by eliminating the alternator? The short answer is 'no'. Consider the power formula P(watts)=I(amps)xE(voltage). And we know that 746 watts = 1 HP @ 100% efficiency. So..... if you were continually drawing 30 amps from your 14.2 VDC alternator output, not likely, that would be 426 watts. Then 426/746 = .57HP required for the power draw from the alternator. The belt-drive for the alternator might cost you an additional .25HP. Grand total? .82HP required to draw a continuous 30 amps from the alternator. Bottom line? Using an alternator on your race car costs little, if any, in terms of lost performance. -Dave-
So you gain very little by not running an alternator. Now we should talk about what is gained by running alternator. My engine builder states the loss of HP by running one outweighs the amount lost when the voltage in your battery drops. Keeping constant voltage actually will help you by not having any drop through out the race. This is especially true for those extended length races.
True. The loss, if any, experienced by running an alternator is far outweighed by the constant, higher voltage out of an alternator/battery combination to the ignition system. Many moons ago, we had a dual sidedraft Weber 2.0L SOHC Ford on an engine dyno in Columbus, OH. Initially powered by a full- charged 12.5VDC battery. We pulled the engine a couple of times & jetted the carbs/set the timing for best fuel-curve & TQ/HP output. The ignition system contained a Pertronix module in the distributor & a Pertronix coil, all with new ignition wires/cap/rotor. Then we suddenly got a bright idea. We did nothing more than attach a 14.4VDC battery charger to the previous-pulls 12.5VDC battery. The HP of the engine increased by 4.5 HP! Proof positive that most ignition systems will yield more TQ/HP if operated with a good alternator/battery combination at a higher voltage. And you make a good point that the system DC voltage is relatively constant throughout race day when using an alternator. With no battery charging required between races. And the age we now live within, a 30-40 amp alternator can be purchased that, size-wise, is not much larger in diameter than a clenched fist! -Dave-
And that may well be the deciding factor, a mini alternator with a light weight mount will probably take off 5-10# of front weight versus the early stock mustang/ pinto alt and stock mount.
I have tried with and without a alternator and everytime without one I lost on my lap times. I would say this is more from the loss of ignition power than anything else. But when you see a 1-3 tenth difference from what you normally run then it is not worth not having one. 1st time was with a stopwatch and the second time was with the transponder system.
Thank you for your knowledgeable responses! This is actually for a Wissota Mod 4. I'd say every other driver in the class runs without an alternator and I was told I should as well. I think I'll keep mine on and perhaps look into a mini alt and lightweight bracket. Thanks again!
Dont get sucked into the what everybody else does mindset... 1/2 of that may be true and 1/2 to keep you that much slower than them.