11 replies to this topic

[850drag]

Hey guys, i was wondering if anyone has tried building an alternator cut off switch into there system, any recommendation?? I am probably going to do this but before i started i just wanted to see if anyone has any experience?

Thanks


Aaron

[jross]

Why would you want to do that?

[prasamin]

i'm a little curious about that also...what benefits do you get from turning off the alternator?...i don't quite understand what you are doing here...no sarcasm, just sheer curiosity.

[jross]

Yea.. I mean, the alternator kind of runs the car, ya'know? Seems like a bad idea to shut that off...

[850drag]

your alternator eats up horsepower, anywhere from 5 to 10 hp and that is hp that i could use, you cut the alternators power off when racing and flip it back on once done, my I did some research and came accross this and my teacher at school also said alot of dragsters do this, you see your alternator runs off of the engine which in turn eats your hp.

[prasamin]

so if you cut off the alternator, wouldn't you drain the battery or something?

i could see it robbing you of horsepower, but maybe you should look into this a little more...maybe on drag racers cars they have custom wired things to bypass the alternator...i'm sure there is alot more tied into the alternator on a Volvo than just the battery and engine! i don't know much about this though!

[The Poi]

eh, your car may already do this, it probably does it with the AC conmpressor to, but im not entirely certain.. if it doesnt, just put a microswitch on top of the pedel. Wire it into two Bosch relays that intercept the cont wires going to the AC clutch and the exciter wire on teh alt. have the switch disconnect both when the throttle is past a certain distance. Make sure you have a good battery, witht eh alt gone theres gonna be a good reliance on the battery. No loud music.....

edit:// i drove my car for a week, maybe a total of 10 miles, with the alternator "off". With the stereo on (no amps). Killed the previosuly fresh Costco battery. That was hilarious.

Edited by The Poi, 26 October 2004 - 05:18 AM.

[850drag]

so if you cut off the alternator, wouldn't you drain the battery or something?

i could see it robbing you of horsepower, but maybe you should look into this a little more...maybe on drag racers cars they have custom wired things to bypass the alternator...i'm sure there is alot more tied into the alternator on a Volvo than just the battery and engine!  i don't know much about this though!

here are the power robing accessories:
A water pump takes 10hp to drive, an oil pump takes 10hp and the alternator can take up as much as 35hp. Use a low drag water pump or electric drive and put a switch on the field of your alternator to turn off the drag during the run.

I will look into this further but if anyone has better knowledge on this please let me know, thanks

and yes you would drain the battery but this is why you would put a switch in, to turn it right back on after the race, of course all your accessories will be turned off too, like listed above.

[jross]

Yeaaa... you might want to rethink that, bro. No offense, but I see serious potential problems in what you're suggesting. I mean, for one, it's going to kill your battery, so you'd need two, but to run it properly you'd essentially need two electrical systems, and it would get really complicated...

[ROB @ VMS]

Sounds like a bad idea, system voltage is just as important when making hp. Your ignition system would not like this very well at all. Bad idea, 10hp isnt even worth the risk for something like that.

[The Poi]

Yeaaa... you might want to rethink that, bro. No offense, but I see serious potential problems in what you're suggesting. I mean, for one, it's going to kill your battery, so you'd need two, but to run it properly you'd essentially need two electrical systems, and it would get really complicated...

its not hard or damaging if you keep an eye on whatcha doing. You shut the alt off just by cutting out the exciter wire. one tiny wire, real simple. and as long as you dont overwhelm the current capacity of the battery you'll be fine. Just need to keep the battery charged, hence you limit it

[850drag]

thanks for all your responses, they are very helpful, after looking at a wiring dia of my car it looks more complicated then I thought, it looked so easy on my teachers car, oh well, i still might do something of this nature, i will have to see.

Edited by mcevoy, 26 October 2004 - 11:21 AM.