alternator cutoff switch?

the98stang

Active Member
Aug 12, 2005
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Clovis, CA
Ok this might be a gay idea, but has anyone every made a switch that cuts off the alternator power so the engine doesn't have to work as hard, therefore making more power? Would this work? I did a search and apparently no one has done anything like this before. I thought it would be a very simple mod to make some extra ponies. Any thoughts or ideas? Thanks guys..

Tanner
 
BAD idea. Your battery is ONLY for starting, and as a power filter. Your alternator is responsible for powering everything in your car, computer to COPs. There is no drag with the alternator, unless it's going bad. It should spin as free as an idler pulley. If you want to reduce some of the parasitic loss in the belt system, get an electric water pump, ditch the A/C and power steering and go manual rack, and get an underdrive pulley set.
 
Shiroelex said:
BAD idea. Your battery is ONLY for starting, and as a power filter. Your alternator is responsible for powering everything in your car, computer to COPs. There is no drag with the alternator, unless it's going bad. It should spin as free as an idler pulley. If you want to reduce some of the parasitic loss in the belt system, get an electric water pump, ditch the A/C and power steering and go manual rack, and get an underdrive pulley set.

So you think the battery would drain even if the switch was used for only a minute or less? Or are you saying the ECU/COPS/PATS would get screwed up?

This was just an idea lol...I wanted to know if it would work affectively.
 
I'm not sure how long our cars could go without the alternator, but the 440 in an old Dodge Ram I have only lasted like 3 minutes without, and it ran like butt. I'm sure any high RPM activity would quickly kill off your battery.
 
the98stang said:
So you think the battery would drain even if the switch was used for only a minute or less? Or are you saying the ECU/COPS/PATS would get screwed up?

This was just an idea lol...I wanted to know if it would work affectively.
You'll be able to drive around town without the alternator for a good bit. Expect the in-dash battery light to go off on you at the upper rpm.

But I agree with Shiroelex on this one. Bad idea.
 
The only way to do this would be with a deep cycle (marine) battery and have a clutch installed on the alt pulley, like what is on the AC.

If you just 'turned it off' with a switch, the alt will still be dragging on the engine because its connected physically to resistance..

Anyway, this wouldn't be worth much HP at all. Maybe 1.