Hey guys w 94/5 gt's w under drive pulleys did y'all experience an amp loss w them- dim lights etc? My 90 came w em and I had to add a higher amp alternator to compensate. With the stock 130 amp on the sn's is there an issue?
SN95 U/d Pulleys And Amp Issues?
- Thread starter 90lxwhite
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You don't need a higher amp alternator. At best, you are probably using maybe 100A tops at full load.
The issue is pulley RPM. The alternator does have a minimum RpM required to output 12v. The underdrives have slowed the accessories down. You need to spin the alt slightly faster to compensate.
Stock Sn95 pulley is about 2.75". ASP makes ford alt pulleys in 1 7/8", 2", and 2.5" diameters for about $20. You can also use a 2" fox mustang alt pulley. Keep in mind with these pulleys you may need a 5/8" ID washer as a spacer to keep the pulley from hitting the alt case.
The issue is pulley RPM. The alternator does have a minimum RpM required to output 12v. The underdrives have slowed the accessories down. You need to spin the alt slightly faster to compensate.
Stock Sn95 pulley is about 2.75". ASP makes ford alt pulleys in 1 7/8", 2", and 2.5" diameters for about $20. You can also use a 2" fox mustang alt pulley. Keep in mind with these pulleys you may need a 5/8" ID washer as a spacer to keep the pulley from hitting the alt case.
Thanks. Prob won't do pulleys on the 95 but was just curious. I don't think they're worth messing with.
They came on my 90, so I can't give a before and after. All I know is its slow w dim lights.., well not so dim since 90 amp alt but u get the gist
mikestang63
SN Certified Technician
If your alternator is not producing good voltage at idle with under drive pulleys, I've found the fix. Put big heads and a giant ass cam on a stroker engine that has to idle at 1000 rpms anyway, and it all sorts itself out.
Kurt
Kurt
