6G Alternator what I have found

no164ford

Registered User
A few things I have learned about my 6G alternators. I have no proof to back these results but this is what happened to me.

1st one I put on was from a 2001 Mustang V6 factory Motorcraft with stock 2"ish SC pulley on it worked great 14v at Idle on the dyno up to 6000 rpms lowest was 12.8ish. First time I road tested took the car up to 6650 rpm 2 times alternator fried. I figured no surprise it was a u-pull special

So I ordered a new upgraded one 130A NEW not rebuilt.

2nd one Put it on the car stock SC 2"ish pulley took it for a test run car going way lean 13.2's AFR at 5800 did a data log found that at 5200 rpms my voltage dropped from 13.5ish to 11.25 by 5400 rpms the car quit charging and my maf voltage started to drop from 4.12 down to 4.06 making the car go lean. As soon as the rpms came back down the car would start charging, I data logged this 5-6 times to verify.

After talking to Dave Dalke about China made voltage regulators (in the new alt) and possibly over driving the 6G alternator I went back to the u-pull picked up 2 more 6G alternators from 2000 and a 2001 v6 Mustang both factory Motorcraft.

3rd one I installed, one of the u-pull alternators but instead of using the SC pulley I used the larger 2 1/2"ish Mustang 6 rib pulley to slow down the rpms took the car for a test data logged 3-4 pulls up to 6600 rpms voltage held at 13.0ish and 14.0ish at idle, This is great because I have tried at leased 6 stock SC alternators and never could get more then 11.7 volts after 6000 rpms.

Like I said I have no proof but I wanted to post my results so someone don't destroy there motor because they changed there alternator.
 
My alternator repair guy told me the same thing about the 6g. I have taken a few 3g alternators to him for a full rebuild and I've never had a problem. The first two were 135 amp and I just decided to have the last two rewired to 200 amp. He said the Mitsubishi alternators that come stock on our cars are a much better unit than the 6g. Fwiw I never see voltage drops below 13 at wot period.
 
I might try having the 3g upgraded if I have any more problems. But I never had luck with them in the higher rpms 11.7 volts all the time. Do you run under drive?

My alternator repair guy told me the same thing about the 6g. I have taken a few 3g alternators to him for a full rebuild and I've never had a problem. The first two were 135 amp and I just decided to have the last two rewired to 200 amp. He said the Mitsubishi alternators that come stock on our cars are a much better unit than the 6g. Fwiw I never see voltage drops below 13 at wot period.
 
No under drives for me. My guy sends the stator to Texas to have them rewired and upgraded. I've never had a voltage issue.
 
Yes but Dave you have only driven your car about 60 miles so that doesn't count.


:D
Eh I've got about 5500 on it now lol. I just listen to my alternator starter repair guy like I do you on my motor and everything else. I talked to him about the 6g and he said why would you do that lol.
 
I originally had the under drive pulley set on my 91 SC with a 6.00" diameter crank and 3.00" alternator pulley. On the stock alternator with this configuration, I wasn't getting enough voltage at idle (low 13s cold and about 12 volts hot idle) and peak voltage was dropping to about 11.5 volts at 6500-6600 rpm. Switching to a custom 2-5/8" helped to increase idle voltage to high 13s cold, but at WOT on the top end of the track I was still seeing voltage drop to around 11.5 volts.

After trying a couple of stock SC alternators without an improvement, I switched to a new 6G alternator a few years ago and it made better voltage at idle and WOT. First one I bought was an Ebay unit with something like 110 amps, then I later swapped it out for a 170 amp unit I bought from Corey's alternator guy. It worked only slightly better than the Ebay unit, that I'm now keeping as a spare. This thread details some of my experiences with the 6G.

http://www.sccoa.com/forums/showthread.php?107109-6G-alternator/page4&highlight=6G+alternator

David
 
So is there a consensus on how best to proceed? Dave...?? You haven't said much about this.
 
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