Hello. I have a 2014 Z51 and I'm swapping out the alternator for a 320A high output alternator with a smaller pulley. Does anyone know what size the new belt needs to be?

 

Why swap, if I may ask? I don't recall anyone discussing having an output problem.

 

I'm upgrading my stereo. I'm pushing 1500 watts right now, but it's increasing to 4000 soon. I just want to make sure the electrical will support it.

 

Sorry, I cannot help with the belt size. Just a quick question, have you checked to make sure the Corvette electrical system can handle a high output alternator? The BCM can be very finicky if the amperage or voltage isn’t within specific parameters. You might start throwing codes with the new alternator, just my .02. Let us know how it turns out.

 

^^^
Good post.

 

4000 watts! ?

 

4000 watts!??? My ears are bleeding just reading that!

 

With that power and an appropriate converter you could power your house in an outage

 

Likely a long shot but curious if you swapped alternators and how that went?

I swapped my OEM for a Mechman 250amp and have a pesky P0621-00 code along with intermittent random codes and odd behaviors.

The Mechman retains the same pulley size. I bought an OEM belt and belt tensioner that got lost in shipping and arrived after the alternator. Since my drive belt looked great and I was pressed for time, I reused the belt. Charging System warning displayed on the dash when Ignition on Engine off but zero warnings or lights when driving. I put 150 miles on the car so I chalked it up to ECM needing to relearn. Not long after, I got a slew of codes and Service Rear Axle and Stabilitrak warnings.

Belt slip was a possibility, but I saw no signs of belt residue. I installed the new belt and tensioner anyways. The original tensioner was super mucky. Testing after the install was brutal. The Z06 made a 2 second attempt to crank and stopped with Charging System and Reduced Engine Power warnings. A second attempt had no action. Checked codes...let it sit....tried next day. With engine on, the idle was terrible and chugged off. 2 more attempts with crappy results. Put the battery charger on. That night, attempt 1 was like earlier. Attempt 2, I gave it plenty of gas and idle cleaned up after but a minute later, chugged off. Repeated and it seemed to self correct.I'm about to try a test run but the P0621-00 code remains. Most of the other codes are gone minus HVAC and Human Tele-something modules lost communication.

 

On C5's the alternator needed to be a match to the car, so most had the oem rebuilt. Not sure if the C7 is like that also.

 

That is a lot of power from the stereo system.

 

True!

 

Too early to tell but last night, I disassembled the 2 wire connector to the alternator to see if I had a wiring problem. I re-seated the wires and started the car. No battery light, no warnings for Charging System, Rear Axle, Engine Power Reduced, nothing period. I drove it 3 miles and no issues. Makes perfect sense:

1. The Mechman 250amp alternator was charging the battery during the 150 intermittent miles.
2. Ignition on Engine Off showed a Charging System Problem warning. Car clearly can't charge with Engine off.
3. A faulty signal wire to the ECM triggers warnings and the ECM makes incorrect adjustments to drivability like idle and rear differential.

I changed my alternator for audio reasons like Dave. His 4k watts blow me away but after I changed doors to 3 way components, swapped rear speakers for Kickers, added American Bass HD10" sub, and CT Sounds 1k and 1.5k watt amps, my Battery Voltage reading looked like it had ADHD. My amps would cut out after 20 minutes and the battery as tested by a multimeter would be < 12amps. Got a new battery and that didn't help.