Thread: Tuff Stuff 1 Wire Alternators

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Are any of you running one of these? If so, how does it charge at low rpm's? I've got to buy a new alternator since mine isn't charging enough and never has charged worth a crap at idle. I'm looking at the one linked below. Any input is appreciated.

Tuff Stuff Performance 7127NDP - Tuff Stuff One-Wire Alternators - Overview - SummitRacing.com

I'm not quite sure why these large GM style alternators get used, they are very ugly and can be awkward to mount, I much prefer the small Toyota/Denso type, they are much smaller, have high output and more reliable. You must have lots of them in the wrecking yards by now ???

I know you're asking about a alt.Are you reading 14 while at a idle??.What is the current output of your alt??.What size cable are you using for the battery to ground,engine to ground,charging wire??. The min's for grounds is 0/1,and the charging wire should be a number two wire.Could it be that your current wires are two small??.Just if I can trying to help you save some money.

Steve - which Toyota ones work best? It looks like every Toy has a different version. I've one of the GM's with the offset clocked mount on my car and I can assure you that it is beyond a PITA plus way too big. I also want to do a low mount and that's almost impossible with what I have.

Heck - what's another winter car project

I run a one wire on all the cars I build never had trouble mounting ....but then I use chevy engines....EXCEPT on my ford 8N which I changed to 12V neg. ground and that has a GM style one wire on it also. just what your used to I guess

Originally Posted by tidefan66

Are any of you running one of these? If so, how does it charge at low rpm's? I've got to buy a new alternator since mine isn't charging enough and never has charged worth a crap at idle. I'm looking at the one linked below. Any input is appreciated.

I run one in mine. No complaints with it so far! I'd do it again if I needed too.

Originally Posted by 1gary

I know you're asking about a alt.Are you reading 14 while at a idle??.What is the current output of your alt??.What size cable are you using for the battery to ground,engine to ground,charging wire??. The min's for grounds is 0/1,and the charging wire should be a number two wire.Could it be that your current wires are two small??.Just if I can trying to help you save some money.

Checking the voltage at the alternator, not the battery. At idle it only puts out about 12.3 to 12.5 volts. Raise the rpm's a little, say 1000 and it will get up to 14.1 or 14.2 volts and that is with nothing on. Start turning stuff on and it drops especially when the fan kicks in. At idle with the electric fan running it only puts out 11.6 volts which is bad. It's never shown to be charging much if any at idle but going down the road it's fine. It's supposed to be a 100 or 110 amp, I can't remember for sure. The Tuff Stuff looks to be the best one for the money and I would get a 1 wire if it charges good at idle but if not, I'll go with the standard 3 wire.

Are you running relays on the fan??.

The alternator sounds like it's working ok,
there are 2 possible solutions,
1. screw the idle speed up a bit
2. fit a smaller diameter pulley on your existing alternator (about 75% of the current diameter)

I still want to know your taking care of the grounds and charging wire in terms are they big enough.You would be very surprised how limiting a poor ground/charging wire can be.

One from the battery to a good ground to the chassis

One from the engine to the chassis.In both cases to the frame

If the low voltage causes you concern, then change the alternator pulley. Alternator voltages aren't usually measured at idle. Power Master sends a sheet with their alternators that shows what voltage it was delivering and at what RPM. They also give you an intended RPM range to work in. Over speeding an alternator happens when mixing and matching parts, and no one remembers to verify alternator rpm. Sounds like you need to figure out what's the rpm range you motor spends most of it's time and then dial in the alternator speed to meet your needs.

As an example, consider that the pulley size on the alternator may be 1/2 the size of the pulley on the crank. So the potential exists to spin the alternator twice as fast as the motor is turning. When your spinning the motor at 5 grand, you could be spinning the alternator at 10 grand! They won't last long at that speed!

Street Rodder did a great write-up on this a few years back. In any event, figure out what rpm your alternator is running at (at idle) and if you have a local rebuilder available, check with them to see if a bigger or smaller pulley is on hand, make the change, then verify if your getting the intended results.

I've been running one a long time with no problems. Once you rev to
2000 rpm it will continue to charge until you shut it down. You just have
to excite it a little. Also put on on my tractor with no problems.

Convert it back to a three-wire alternator and you won't have any problems. Read this:

Catalog

I will never use a one-wire alternator again given the problems they have and from I experienced. Since I converted mine back to a three-wire, all my problems went away.