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1997 Corolla Aftermarket Stereo Problem

By Guest daemorok, October 9, 2010 in Pre-1997 Toyota Corolla and Geo Prizm

Guest daemorok

Having a slightly odd issue with my stereo. Basically all the speakers which are amped (1 10" sub 2 and 6.5" coax on the back deck) cut out or get quiet in certain situations.

The more accessories I have going (wipers, AC, lights, etc) the more often it happens, it usually occurs when i hit the breaks.

Here are the specs for the system:

Pioneer head unit (older model 4x65watt output)

Dedicated sub amp, bridged to 300watt RMS running a JL 10w3v3

Dedicated Rear amp, 2x65watt RMS going to blapunkt 6.5" coax on the rear deck, also 65watt RMS

2 Farad Cap inline before the splitter that goes to the amps.

Wiring from the battery the cap to the splitter to the amps is 8g

Wiring from the sub amp to the subs is 8g

Wiring from the rear amp to the speakers is 12g

My thinking so far is that the alternator (70amp) can't handle everything.

So two part question:

Am I on the right track with thinking its the alternator

Is there a more powerful alternator available for my car.


Very possible that the alternator cannot keep up. Have you tried monitoring the voltage when this happens? You can get a cheap inline voltmeter, and see if the voltage drops too low. The sign that it is likely the charging system, is when you come to a stop. Amount of power from the alternator is directly proportional to the engine speed - at highway speeds is when the battery gets charged up the most.

Options for a Corolla are limited - you can run a higher capacity battery (larger battery, run two smaller batteries in parallel, or run a deep cycle). That will help keep the voltage level up in periods that the car is idling. As for a high output alternator - not much, unless you get your OEM one rewound (keeps everything in the stock location), or run an aftermarket alternator and fabricate a different bracket/v-belt for the system. In any case, still would need to run a beefier battery, as these high output alternators put out close to stock or even less power than OEM alternators at idle - they only start pushing more juice at higher RPMs.

Wiring is plenty thick enough - I'd double check that the connections are still clean/tight - no corrosion. Also double check that the wiring to the amps themselves are in good shape, no nicks or cuts in the wiring.

What is the normal output for a 8th gen corolla alternator? Volts and amps?

Specs have the alternator at 80A

Unloaded voltage @ 2000 RPM should be between 13.5V - 15V

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