[motorhead6776]

im planning on buying an under drive pulley soon and i want to get as much out of it as i can so i wont be buying an overdrive for the alt. i have one 1100 watt 12" sub with an 1100 watt amp that draws up to 30 amps of current. would i be able to get away with buying a capacitor to go with my sub instead of buying an overdrive for the alt. if so what size capacitor?

[04DSGV6]

I know this isn't very helpful but I'd see if you can run the UD's without a problem before the cap. Im speaking out of my ass but I don't think that the UD set lowers your alternator that much for a simple not crazy audio set up. If it fails worst case you just buy a cap and we all learn a lesson on here.

[motorhead6776]

yeah, one of the other things i was worried about was over working the alt because ive heard of people who have ruined them with a high end audio setup. i think ill just buy a small capasitor anyway because it will stop my sub from cutting out at high volume anyways.

[Bullitt2445]

An amp with 30 amps of draw really isn't taxing much. Even at a loud volume, A/C on, headlights and such, you should be around 90 amps total for the alternator to keep up. The only reason you need an overdrive pully on the alternator is to keep it's speed up at idle. Your car's alternator puts out I belive 105 amps at 2000 RPM and 95 at idle, so I would try just the underdrives and see how it works. Most kits come with the correction pulley for the alternator and the water pump, so you may be OK.

[Trick Tuners]

Get a cap for sure! My friend has the 12W7 and 1000W amp in his truck with a 200A alternator and 1fd cap and it still blinks the headlights bad with the bass notes. It may draw 30A but the peak loads could be much higher especially if you have smaller than 4g wire. He just wired 0 gauge wire and added a 25Fd cap. I would upgrade the alternator and get a cap. The car draws tons of power for regular operation (fan, hvac, injectors, fuel pump, coils, etc). Headlights off i sometimes see a drop in voltage of about 1V on a 3rd gear pull just due to the increased load on the fuel and spark systems. (and the alternator is spinning faster while the voltage is dropping!) When i had my old speakers in my mustang i could datalog a 1V drop in battery power over about 10-15 seconds by turning the stereo up loud.

[wraitherx]

are your amps and subs 1100 watts max power or rms? If not what is the continous rms rating and at how many ohms?

[mxnate116]

Originally Posted by motorhead6776 yeah, one of the other things i was worried about was over working the alt because ive heard of people who have ruined them with a high end audio setup. i think ill just buy a small capasitor anyway because it will stop my sub from cutting out at high volume anyways.

if its cutting out at high volume i dont think its a power supply issue. your clipping the amp. which with kill your amo and sub if you keep it up. it sounds like your gains arent set right and your overdriving the amp.

i highly doubt your amp is pushing or your sub could handle 1100 watts. if it only pulls 30 amps its nowhere near that. my 400watt(RMS) class d amp pulls 35 amps.

also a capacitor is only a bandaid for the problem. it just manages power spikes. the alternator will work just as hard to recharge the cap as it would without one.

take the money you would spend on the cap and upgrade all the power and ground wires under the hood to at least 4 guage

[00redgt]

caps are useless.just get a optima battery

[fogged306]

Originally Posted by mxnate116 if its cutting out at high volume i dont think its a power supply issue. your clipping the amp. which with kill your amo and sub if you keep it up. it sounds like your gains arent set right and your overdriving the amp. i highly doubt your amp is pushing or your sub could handle 1100 watts. if it only pulls 30 amps its nowhere near that. my 400watt(RMS) class d amp pulls 35 amps. also a capacitor is only a bandaid for the problem. it just manages power spikes. the alternator will work just as hard to recharge the cap as it would without one. take the money you would spend on the cap and upgrade all the power and ground wires under the hood to at least 4 guage

+100000