Upgrade alternator??

I have a 1991 supra impulse with a 351 in I'm looking to add an amp and subwoofer to my stereo system, I was told to get a 100 amp alternator to keep up with the stereo draining the battery, having trouble trying to figure all this out,
Any help or input would be great....Thanks on advance.

Jeff

I put in a pretty hefty size amp (5ch) to run 8 speakers and a sub in my 92 conbrio/impulse. Didn't upgrade alternator and have had no problems, but have noticed that my volt gauge sets lower than it did prior. I will be upgrading mine over the winter, as I also plan to add another amp and 2nd battery dedicated to the stereo.

DB electrical has the best prices I have seen so far on upgrades.

Thanks for the reply that's what I was thinking I'm going to be running 2 tower speakers and the sub off of the amp.....

Alternator is probably secondary to adding another battery. I'm a fan of the blue-sea add-a-battery kit, but there are other options. You want to make sure you can crank your stereo for a while and not worry about killing your starting battery. An isolator will take care of that for you.

I'd also add an on-board charger/maintainer (but I got sick of being stranded or having battery problems a LONG time ago.)

Jeff,

Simply adding "an amp" is far from needing to upgrade the alternator in order to keep pace. Let me ask a few questions:

Whats the makeup of the existing audio system
What amp are you adding
does the boat have 1 or 2 battery banks?
Do you use an onboard charger or other shore charging used
Do you spend a lot of time at anchor playing the system

Current system is head unit and 6 speakers, speakers are run right off the head unit. 2 tower 8"speakers and 4 internal 6.5", I'm adding a 4 channel 1600 watt amp and a 12" 250watt rms sub.
Boat currently has a singal battery, mostly listen to the stereo while riding but will listen to it on the beach also at times.........charge battery as needed when boat is on the trailer....

Do you by chance know the amp model? 1600W (which is in in AC) is a marketing number and means little when calculating what the average DC current draw will be. I presume you will be leaving the 4 in-boats on the head-unit and relocating the 2 tower speakers to the new 4 chnl amp along with the sub?

I would put my money into a Blue Sea battery switch, a group-24 deep-cycle battery rather then an upgraded alternator.

Amp is a BOSS 1600.4, yes I will be putting the 4speakers in the boat on the head unit and the 2 tower speakers and sub on the amp, I will also be putting a group 27 deep cycle in.....

Realistically, I dont think that amp is going to draw more than 25A DC. Id say about 200W rms to the woofer bridged and about 50W rms for each tower speaker.

Good to get a second opinion, I appreciate it, I think I'll try as is and see what happens...Thanks again!!