Alternator going out? "check charging system"

[05moneypit]

I was just thinking you have a big OD damper right? If so that alternator is getting whipped! That may explain the spikes. A OD alternator pulley wouldn't be a bad idea.

Thought the same thing earlier this year. Made a 3.5" pulley for the alternator to slow it down. Max RPM I believe the alternator is seeing now is 14K-15K.


That data log is with the engine at idle.

 

[Department Of Boost]

Battery in trunk. Grounded to welded in roll cage.......

That should be fine.

But I also at one time ran a seperate (1/0) ground cable direct from the battery to the engine block...... Made no change.

I've done the same test, no change.

Battery feeds directly to the BEC on the fuse block.

So the pos battery cable goes to the fuse block? The alternator cable goes to the fuse block? And the starter hot cable goes to the fuse block?

We have three cars set up like this. Works good.

Alternator is in stock location.

Had a powder coated alternator once but have the new OEM on it now.

It shouldn't have a ground issue then. You can test if it does real quick though. Just run some 2-4ga cable from the alternator case directly to a chassis ground and see if things get better. This is a long shot though, I wouldn't put money on it.

Thought the same thing earlier this year. Made a 3.5" pulley for the alternator to slow it down. Max RPM I believe the alternator is seeing now is 14K-15K.

To quote my buddy who own the alternator company when I asked him how fast a 6G could be spun:

"If it is spinning at all it's spinning too fast".

Obviously an exaggeration, but it does show what he thinks of the 6G design.

In theory you aren't spinning your alternator very fast. That said I have seen them come apart in just a few miles. They are time bombs. You may have gotten two junk ones in a row. My neighbor has a stone stock (well at least until last week) 08' GT and it has had 5 alternators put on under warranty.

That data log is with the engine at idle.

Now that is interesting. I'm going to need to think about that/ask some questions of my friend.

Have you done the voltage test at the alternator/battery that I outlined above? I would be interested in the exact numbers you are getting.

I'm sending you a PM right now.

 

[BruceH]

Jason,

When is your replacement alternator going to come out?

 

[Department Of Boost]

Jason,

When is your replacement alternator going to come out?

Technically its out. We have a whole bunch of cars with them.

We're planning on doing a "Grand Opening" for DOB in about 45-60 days. Sponsoring forums, magazine advertising, releasing everything we have been working on, etc. When we "open" we will have 200A GT, GT500 and GT Supercar alternators (we've been testing all of them).

We're trying to figure out how to put 135A Denzo alternators on 05-09 cars too (there is some trickery involved) so we have a better option but without the 200A alternators price.

 

[fdjizm]

Good to hear, I'd be interested in the 135a!

 

[Timmbo]

Technically its out. We have a whole bunch of cars with them.

We're planning on doing a "Grand Opening" for DOB in about 45-60 days. Sponsoring forums, magazine advertising, releasing everything we have been working on, etc. When we "open" we will have 200A GT, GT500 and GT Supercar alternators (we've been testing all of them).

We're trying to figure out how to put 135A Denzo alternators on 05-09 cars too (there is some trickery involved) so we have a better option but without the 200A alternators price.

And.......you will have a 3.4L Whipple DOB R spec manifold kit waiting for me soon right??? I'd like to at least be towards the top of the wait list please lol.

 

[irishpwr46]

I have one of our 200A alternators. It is making good power, right at 14.4v where it should be. But I was seeing voltage as low as 12.7v at idle while sitting at lights. End up my battery which was “good” just couldn’t get the job done. I put one of the new Interstate billy bad @$$ batteries in and things got a LOT better. But not perfect. It stopped freaking my gauges/shift lights out and stopped throwing codes. But if all the fans were running, which they are most of the time sitting at lights it would pull the whole system down 1-1.2v. We ended up putting a slightly smaller custom clutched pulley on the alternator and bumping the idle to 1000rpm to spin the alternator faster at idle.

And this is a system with “double ought” battery cable and 2ga alternator/ground cables!

Obviously my blue car is running a lot more electronics than most. But the above is a good demonstration of how hard these cars are to charge. I’m beating the snot out of a 200A alternator. A 135A alternator (stock) wouldn’t stand a chance. 135A alternators aren’t real happy running the electrics on your basic FI setup. Let alone a weak 135A alternator/battery which is the case a lot of the time.

have you ever considered a capacitor? would that help at all?

 

[Department Of Boost]

have you ever considered a capacitor? would that help at all?

If I understand how a capacitor works (I may not) I don’t think so. The electrical loads are constant (for the most part) so there would be no time for it to “charge up”.

 

[Sky Render]

have you ever considered a capacitor? would that help at all?

No, capcitors "smooth out" brief voltage dips. GMitch's electrical loads are mostly constant, as he said. Capacitors are only used in very-high draw sound systems to prevent dips during "hits" of bass.

The electrical engineer in me would like to point out that everything GMitch has said about electrical systems in this thread is 100% correct.

Sent from my toilet using Tapatalk

 

[05moneypit]

I was wondering if one of you guys could do a data log like the one I have below with "generator duty cycle" and desired alternator voltage. I would be interested in seeing what your duty cycle is at idle.

My log below is with the car at idle and no lights or anything extra electrical running. From what I can see in my logs the "CHECK CHARGING SYSTEM" message comes on when the duty cycle spikes.

Thanks!
Lee

 

[fdjizm]

Swapped the alternator took about an hour.
Had to remove my TB and water pump pulley. I have the steed UDP's and it gets in the way of pulling out the bottom mount on the alternator.

So far so good! Should I get the OEM one rebuilt just to have a good spare?
Autozone would give ma back $10 core charge which doesn't mean shit to me lol.

 

[tomkay]

I have a 2008 and my alternator is labeled rebuilt. Just last week I was taking my daughter to work and I hear a weird snap and smells like something burning. Next loud whining like a bad power steering pump and I think great my s/c bearing is going again. Make it back home and pop the hood to see where noise is coming from but couldn't tell for sure. As I'm looking I see 2 bolts hanging out the back of my alternator. I remove it and sure enough 2 of the 3 bolts that hold the alternator halves together are broken, only 1 bolt was holding it from falling apart completely. I run to Lowes and pick up new bolts, line it up and bolt it back together, so far it's quiet and working but still not sure why the bolts would break.

fdjizm, I saw rebuild kits for around $35-40 online which included new brushes, bearings, regulator, etc.