I maybe in the position to replace a alternator on my 98 Coupe. I read about a High Output version on the forum, but WHAT advantage does a 240/275 Amp provide a stock C5 car. Company talks about amps at idle and the lack of power to Stero/A/C/Electrical sytem/and the power to the onboard computers that control our vehicles.

 

I've heard of problems with the PCM not communicating to regulate the alternator, if an exact replacement alternator is not used. I'd be very cautious about installing anything else.

 

IMO the stocker is just fine, it's pretty high output already. Unless you have a HUGE stereo system and super high output ignition, you'd be wasting your money, and also the PCM could get angry as stated above.

 

A properly operating C5 and or C6 OEM Alternator is perfectly capable of providing all the power you need to run the vehicle with EVERYTHING OEM ON. Like Blown427conv stated, if you start adding power robbers or significantly reduce the drive belt speed with a under drive pulley, you may have power issues other wise you should be fine.

The problems comes when the system starts to break down and reduce alternator output or current/voltage in the electrical system thru high resistance connections.

Here are a few areas that significantly reduce the voltage and current available from your alternator or electrical system:

- Poor condition and or corroded battery terminal connections at the battery.

- Bad crimp connections at the battery cable to screw on terminal joint (Under the RED and BLACK terminal rubber boots

- Bad electrical connections at the starter solenoid. The alternator charges the battery THRU the connections on the alternator.

- Poor connection on the BATT terninal on the back of the alternator

- Loose batery terminals. 1997-2003 need 11 ft/lbs TQ for proper connections. 2004+ need 89 inch/lbs

- Ignition switch failure. The contacts inside the electrical portion of the ignition switch carbon up and when you turn on the ignition, the output of the switch is far less than battery voltage. Ive see as little as 8 vdc.

Poor grounds. The MAIN grounds for the chassie and engine are G-104 (on top of the frame next to the battery, and G-106 passengers side of the engine block above the starter. They MUST be in 100% condition or the rest of the electrical system will not work properly. The rest of the grounds are just as important for the circuits that they support.

BC

 

I actually installed a high output alternator in my 03 C5 and had major issues. My car kept getting "HIGH VOLTAGE" warning and it eventually blew my ABS unit.