10 rib "overdrive" alternator pulley

[Angrey]

Looking for smaller (overdrive) 10 rib pulley for Ford style alternator.

I had what I thought was electrical issues (turned out to be a fused starter drain). Replaced the battery and the stats/sensor readings for the alternator were solid.

Decided with my build to upgrade from the 175A OEM unit. Didn't occur to me that the higher amp alternators are a bit of a gimmick (same case sizing and internals, just a smaller pulley). I dunno, maybe they reconfig the internals so that it's made to spin harder to yield 300 amps. Figured with additional draw from a return style system, the intercooler pump, maybe an audio amp down the road I'd like the additional juice.

Well, new alternator comes with an advisory sticker that basically says...don't swap out the small pulley for the regular one or it may not generate enough current at low rpm/idle conditions.

Whipple 10 Rib setup features a pulley diameter (alternator) same size as OEM (2.75").

I specifically went 10 rib and OEM diameter balancer to NOT overspin and create additional wear/tear (especially on the alternator).

So now I've pickled myself between either A) Finding a smaller/overdrive pulley for the alternator in 10 rib (which isn't easy) B) Running the 175A OE alternator, C) Running the 300A alternator with the larger pulley and hoping it doesn't give charging issues or deep battery cycles with idle conditions or D) Bite the bullet and get an oversized crank balancer ($$$) and adjust the blower pulley ($$).

Sponsored

 

[gcadorette13]

I’m way late to this party but what did you end up doing?

 

[Angrey]

I ended up going with the stock pulley size (whipple 10 rib). With all the added draw/load, I have indeed been having E-issues.

 

[horsepower addiction]

You can get the pulley from a 3.8 supercharged v6 like from the 80s thunderbird. Bolts right on. If you overdrive the belt system you can get the alternator pulley from a newer cobra jet

 

[Angrey]

You can get the pulley from a 3.8 supercharged v6 like from the 80s thunderbird. Bolts right on. If you overdrive the belt system you can get the alternator pulley from a newer cobra jet

Those look to be 8 rib. And I'm looking for smaller than stock diameter (smaller than 2.75")

 

[Angrey]

I may have found a solution, although it might be an expensive one.

I spoke with "Power Bastards" and their alternators are engineered and built to provide higher output without the gimmick of the smaller diameter pulley. So I bit my lip and ordered one ($633 with taxes and no sales codes).

It's rated at 320 amps at 1200 rpm, so HOPEFULLY I can run all my additional loads on the car now (which are substantial) without deep cycling the battery. Hell, if it works well enough, I might even be able to go back to the Antigravity setup.

More to follow, but I should be able to swap the 10 rib whipple pulley and see a marked improvement on charging state at lower rpms.

 

[Whitedevil95]

I may have found a solution, although it might be an expensive one.

I spoke with "Power Bastards" and their alternators are engineered and built to provide higher output without the gimmick of the smaller diameter pulley. So I bit my lip and ordered one ($633 with taxes and no sales codes).

It's rated at 320 amps at 1200 rpm, so HOPEFULLY I can run all my additional loads on the car now (which are substantial) without deep cycling the battery. Hell, if it works well enough, I might even be able to go back to the Antigravity setup.

More to follow, but I should be able to swap the 10 rib whipple pulley and see a marked improvement on charging state at lower rpms.

This is interesting, I came from the Terminator world before the coyote and Alternators were always an achilles heel for them. I went through several big dollar aftermarket alternators on them. I was wondering where the threshold for charging was with the stock coyote alternators was. What other types of draws do you have over factory? Mine I think is just the twin pump return fuel system.

 

[Angrey]

This is interesting, I came from the Terminator world before the coyote and Alternators were always an achilles heel for them. I went through several big dollar aftermarket alternators on them. I was wondering where the threshold for charging was with the stock coyote alternators was. What other types of draws do you have over factory? Mine I think is just the twin pump return fuel system.

I have gauges, digital mirror (now) and some other minor things.

Major items are the primary fuel pumps (which are about the same as factory) the intercooler pump (which is the biggest culprit at 36 amps continuous), an aftermarket stereo amp and secondary fuel pumps (which transfer from the passenger side to the driver's side so they don't always run).

Not sure what the amp draws, it's not wild, I think it's max 300 watts spread among the speakers. In any case, the system seems to draw down the battery and it's fine at elevated rpm, but as soon I stop at a light, after a long drive, the system struggles. That tells me that the alternator isn't keeping up to keep the battery from deep cycling and it's REALLY not keeping up at low rpms after the battery is down.

The biggest thing that kills alternators is heat and high sustained rpms. The higher output units are made with better cooling channels to battle the heat and crafted to output more at lower rpms. None of them will survive long term abuse. It's pretty much a wear item. I'm fine not fine with it, but I understand it, I just want the system to be supplied properly when the alternator is actually working.

We'll see if this solves the issue. I had to order special tools to change the pulley. The newer units have an OAD/OAP pulley which reduces loss of spin during shifts. According to this channel, apparently swapping them out for a solid pulley is bad, but it would be the first I'm hearing of the issue since every whipple 10 rib setup is a solid alternator pulley and no one has complained yet. Maybe it is causing issues and no one recognizes it.



in any case, my car was pre OAD/OAP so shouldn't add any further complications.

Sponsored