Hello all. I've got an 02 MCS which I believe has a 105 amp alternator. I love the car, but currently the audio system is in sad shape (front speakers are blown). I would like to add 4 new speakers plus a 10" subwoofer, all with 90db efficiency. I've got an alpine pdx5 amplifier that I'm planning to use to power the whole system, but I'm a bit concerned about two things:

1.)Will my stock alternator keep up with this amp without dimming headlights? I believe the amp puts out 600 w RMS and has 60 amp fuse protection, (gotta love class d efficiency!)

2.)The sub is 30 lb MB Quart Premium monster from my old car, the box is custom made from 5/8" MDF. I plan to mount the amp, the crossovers for the speakers and the capacitor all in the boot under a false floor, but that weight is quickly adding up and I certainly don't want the suspension to sag. I only plan to run the stereo when the car is on, so I was thinking I might be able to get by with an 15 lb ODYSSEY PC680 battery, or maybe the bigger brother PC925? As I understand it, it is the alternator alone than runs the electrics of the car when it is motion. Would the lightweight battery be a smart idea?

3.)I hear the stock wiring for the speakers is pretty stout. Is it stout enough to handle 75W RMS? I'm concerned because the front speakers were infinity kappas 60.5cs and I'm not entirely sure what made them blow (possibly running them off the stock headunit).

Thank you audio gurus!

 

LiquidYellow -

Here are some answers; other posters may have more:

I would be surprised if you NEED more alternator power. The stock mini electrical system a fairly strong, and you're not talking about running a great deal of power. I would not sweat it. If, after you have installed the system, you notice electric shortage issues, especially when running a lot of accessories (e.g., headlighs, AC, etc.) it's not that difficult to add a capacitor after the fact - 1 farad should be plenty.

I say NEED only because, as a general rule, a system with extra capacitance will sound better, especially with bass-heavy material. Thus, while it may not be necessary, you should might want to consider it. If you haven't purchased a wire kit yet, look into the versions that include a capacity (such as kits by Stinger).

I cannot advise you as to your battery question, except to say that any battery comparable or better than stock should be fine, unless you run your stereo with the engine off for long periods of time. Others may disagree.

The stock wiring will probably be fine. It certainly had nothing to do with blowing your stock speakers. Your instinct is likely correct. Your stock radio has limited output capability. When you push it hard, it produces excessive distortion due to lack of headroom. What probably happened was you ran the HU to the point of distortion, which in turn blew the drivers. Could be other things, but that seems like the most likely culprit. I wouldn't look to the wiring as the problem.

Good luck.

 

I appreciate the advice chilisport! Yeah I forgot to say the car is new to me, the front speakers were blown when I bought it (but I do have signal!) Oh and the speaker grills were missing too and they looked like they were kicked in a few times (maybe that's why they didn't work.) I did pickup a tsunami wire kit with 1.2 farad capacitor so I'll definitely be installing it. I've never owned a capacitor before, but I'm sure it will only help and it doesn't weigh all that much.

My main reason for charging concern is because my last car, a 95 3000gt, had a modest audio upgrade from stock: two 10" subs with a kenwood mono amp running 500 w RMS and the alternator died on me on my way to work. It left me stranded on an off ramp of a very busy highway during rush hour. Oh yeah, did I mention it was a blind curve? What can I say, after that mess, I'm a little gun shy about overtaxing the charging system, especially when there isn't a stock voltage guage on my car...

 

That Tsunami cap should work perfectly. Also, if it's the model with a volt meter built in (some caps do), you can check out how the electrical system handles the extra current strain in real time. If the cap is not so equipped, standalone volt gauges are not terribly expensive or difficult to install.

Given your experience, I can understand why you're "gun shy" about overdoing it. My guess is that your 3000gt alt gave out due to age. Also, it may be that the stock alt wasn't selected by Mitsubishi to have much clearance above the car's normal power demands. These days, manufacturers tend to use alts beefy enough to handle additional items, in recognition of the fact that so many mods are being made to cars. The best way to tell if the electrical system is up to the task is to install the system, crank it hard, and run extra accessories. If you notice the lights dimming, you may need extra capacitance.

With what you've got now, however, you should be in great shape.

 

I have an alpine 4 x 75 watt amp with stock wires, Alpine 9887, Polk Momo's 6.5's components in front, Polk DB 690's in back and a 10" subwoofer wth a 300 watt amp in back with no problems.

However, I ran my stereo for 2-3 hours the other day with the car off and I had to jump it. First time I had any problem with it.

My car is a little over 2 years old.