alternator?

[DARK270]

well i had the radio and everything else professionally installed...it was recommended that i not get a cap. because of the cost...it was same baout 400$ for a decent cap. and it wouldn't do that much because the alt. and battery have to charge that too....make sense....it just adds to the thinking that now you have one more thing to charge....so increasing the available power would be best by alt. or battery...or both.....the hids i was looking at say 75w....plus they(pros) say that the new alt..will decrease resistance..etc....i dont know much about that...but it does make sense..even if i lose 4-5hp it would be worth it..also i plan on doing an underdrive pulley change soon...that would boost it 20hp is most cases.....

[MichaelDay]

dark, changing to an underdrive pulley will exacerbate your charging problems. You have multiple problems. First, if the lights are dimming when the bass hits indicates that the peak power demands of your system require a cap. The capacitor is designed specifically for that problem by providing the extra power needed during those milliseconds of bass peaks. Secondly, if you use the stereo much while the engine is off or idling, the starting battery isn't good for extended high current demand without the engine running at a high enough speed to let the alternator provide the required energy to keep up with the load. A deep cycle battery will survive being drawn down and recharged MUCH better than typical starting batteries. Third, your alternator may not be up to the job you are asking it to do and certainly adding an underdrive pulley is the WRONG direction as it will reduce alternator output at lower engine speeds. Fourth, your grounding and or wiring may not be adequate to support the power demands being placed on them even if they were professionally installed.

To answer your original question, your engine develops a fixed amount of power. You can use this power to EITHER move the vehicle faster or to generate more charging current to drive HID's or high powered stereo or any additional electrical loads.

[DARK270]

well i cancelled the order today..not because i dont need it..but because he asked for 150$ more..for install....i think 650$ is STUPId..i'm not paying that....anyhow i'm not sold on the idea of a capacitor....but is they anything else i can do???? also i read about the under drive pulleys...and they are actually three pulleys one of them is for the alternator...so it will charge correctly....amybe this is a better route then i would see horsepower gain....

[CHROMEDCRUISER]

Dark, take a look at your wiring, and definately take a look at investing in a capacitor. Go on over to hi-fi buys or circuit city and see what a capacitor will run you, with installation. If you get the capacitor installed and it doesn't do what you want it to, you can always take it back. Since you had your system installed professionally, do you know what gauge wiring you have? Do you know where the amp is grounded? Like everyone who's responded so far has said, all of these things have to be taken into account, not just the alternator. The 'pros' that you're talking about may be leading you in the wrong direction, it never hurts to go get a second opinion at another audio shop.