freddyvette

Hello all.

I recently ran my 08 C6 Z06 on the track. After a few laps, I hit 230 Oil 240 Water temps. All is good with pressure.

However, once the fans come on, I start losing voltage immediately. The voltages drop rapidly from 14 to 11.5 and I get a charging system warning.

I checked the connections and they were fine, no melting or burned smell. There is a good ground from the harness side pigtail.

To drive home from the track I unplugged the connections to the fan and I experienced the most stable voltages I have ever seen with this car. Normally the DIC reads 13.3-13.9 and fluctuates wildly. With the fans disconnected I had a consistent 14.1 volts all the way home, 192 coolant temp in 70 degree weather at night. I only saw the coolant get up to 212 when I got stuck in traffic for 2 or 3 minutes.

Has anyone had this happen before?

Apocolipse

Yes - the stock alt sucks BIG TIME and is the #1 main issue with electrical grems in this car. When its hot it is even worse.

Save up for a mechman / billetech and your issues will go away.

ratomicZ06

And/Or battery, esp if its older and not kept on maintenance charger.

freddyvette

Right thanks but neither of those are the problem.

Apocolipse

How is the alt not a problem when the exact issue is electrical load related lol

The alt is under sized, the fans go to 90% load at high temps, the alt gives less voltag and less amps when hot...directly related to your problem.

This is also why C6 are so bad on batteries...the stock alt doesnt provide high enough voltage to fully charge.

G8Pumpkin

saccitycorvette.com has a charging system wiring upgrade that may help solve your problem.

freddyvette

Ive never had a problem with either my battery discharging nor heat related issues.

MTPZ06

freddyvette

Alternator tested fine

FNBADAZ06

If I remember correctly, the stock fan can pull a max of 24 amps at full speed (I think the factory tune limits max speed to 90% ?). I believe the stock OEM alternator puts out a maximum of 145 A. My math says that's 16% of the total output.
Don't know if it's a direct correlation, but a 16% of 14.1 volts is........ 11.8 volts.

Apocolipse

Magic math. And it is not 145 at idle. Let me see if I can find a printout for a basic aftermarket replacement alt...this will prove my point.

freddyvette

That's ridiculous plus it puts the system into alarm mode and triggers a service charging system warning

Patriot Six

If the stock fan motor is going, it could put more strain on your electrical system than normal trying to keep up with rising temps. My stock fan actually burnt up my fuse box. Replaced the fan with Prospeed dual setup and no more issues. Alternator was replaced with a Mechman, but only to keep up with the increased draw from the dual fans.

freddyvette

Do you think this is bad?

Bluewheelz

Very typical. I had the same problem. Replace it with the Mechman alternator and a big *** cable from the alternator to the fuse block. Contact Bret (Blownbluez06) here on the forum. He's going to PRI this week but he will take great care of you. Read the reviews.

I now have 14.5+ volts at idle with two 40a Spal fans, two stereo amplifiers at full volume, etc.

Bluewheelz

Battery won't fix the problem. Many of us have tried that. The alternator/cable combo is the fix.

Bluewheelz

Your fan most likely failed due to a low voltage problem.

freddyvette

Seeing as my alternator is brand new and under warranty, if I swap it out it wouldn't be to an aftermarket one just yet. Can you shed some light on the cable to the fuse block routing and terminals/locations?

Apocolipse

Stock replacement have the same problem unfortunately. The only fix is the redesign.

Patriot Six

The cable is a 1/0 cable that goes directly from the alternator to the post near the fuse block in the engine bay. It's merely routed behind the engine.