Is this for real? I see it the newest vendor annoucement.
Anyone know anything about this?

 

I just found it on Alta site.. Link


When using plus sized crank pulleys it is recommended to reduce the speed of the alternator. By installing our 5% ALTA-Nator pulley the speed is reduced further increases HP by reducing parasitic drag.

Hey ...Psst..Randy can you look into this new pulley :-D

 

HaHa!!!!

ALTA-nator

But seriously, I don't think I can keep up w/ all these pulleys. I guess I'll wait till things are proven.

 

again im not educated.. i'd wait for the mechanically known guys to chime in on the subject.. otherwise i guess i found a companion for my 2% crank pulley!

 

My only question is WTF is with this pulley being so much cheaper than everything else?

It would logically take the same amount of R&D as the other pulleys, plus I'm guessing the market for it is smaller, thus increasing price as demand goes down, right?

I think they should all be this price, there is no reason a pulley should be $119-149

 

Hmmm .... It looks NICE

 

Looks like you'll need to lift the motor to get to this part

 

you're right; it probably cost Alta $30 to make that piece. by the time they market it figure $40, so the 2x markup is typical.

Surely you are aware that the SC pulley is two parts, stainless steel, larger diameter and has a bolt hole pattern, threads, slots and tapered bores? so you don't think this should be the same $, right?

 

Soooo im planning on gettin a +2% Crank pulley this wkend at the Chi-town pully party....should I be concerned?

Has anyone w/ a + % crank pulley had any issues w "overdriving" the alternator?...Im so confused

 

Things like the have been used all over the place. Here, you watch to make sure that you get enough current at idle.....

Matt

 

2%? I have that but I don't think 2% will be harmful as long as I keep it under stock rev limit. The guys who have bumped their limit to 7500-8000rpm might have something to worry about

 

Using that logic then, wouldn't the crank pulley be less than that for the SC, since it's only 1 piece?


The SC pulley, ok that is fine at the $109 or whatever JSC sells it for now, but 149 is too much, don't you agree?

 

When u run larger pullys you do have to slow down the "Alta-nator" . I have a 1940 ford with a 383ci SB with a Procharger on it. The kit came with the oversized crank pully and a smaller Altenator Pully to slow it down so that it did not over spin it and burn it up. Just kind of a smart thing to do if your really holding high RPM's. My 383 see's all of 7500 to 8k goin down the 1/4 mile. So its all on how u drive and what kind of setup u have for it to work proper i guess? Im sure someone else could chime in and add to what ive said.

 

CNC parts are costed based on the number of operations, fixturing required and cycle time as well as material. The outer 2-1/2" SC pulleys can be made from bar stock passed through the headstock andif done in a live tool lathe, all the operations can be done on it with the one set-up. (there is the same sort of process for the hub.) The crank pulley has to start from a 5" blank, It is too large to use a bar feeder, so each piece has to be indivdually chucked and then it may have to be re-checked to face the other side. Additional work is needed to machine out the area between spokes. the price seems right to me.

 

Anymore information about the Alta-nata? Why do I feel like Arnold Swartznager

 

I can certainly see where Alta is coming from with this part, but let's say I add a +2% crank pulley and then one of this baby, will this actually reduce the performance of the alternator?

 

With either a 5% or 3% reduction in alternator speed, it's like dropping idle less than 50 RPMs. No big deal. What you'll find is that it won't be spinning any faster than stock (a bit less even) at redline. If you have a REAL BIG pully on the crank, it is possible that you can spin the accessories too fast, creating premature failure. But a 5% change to anything isn't really too much to worry over.
Also, remember that alternators can produce variable current output. That's what it does.... Otherwise it would overcharge batteries etc. So you're alternator will work fine, it just will spin a bit slower, and your wallet will be a bit lighter!


Matt

 

Is this Alta-nata unecessary?

 

On your electrical load, the RPM range you drive, the pully size that you put on the crank and on and on. If you go to a higher redline and/or an overdrive crank pully, maybe it's agood idea. There is no absolute answer.

But I think that this is different than underdriving a water pump for example, where the work into the accessory is dependant on just RPM. For an alternator, if you spin it slower, it may up the current per revolution, so as to meet the electrical demand of the car. so it does some of it's own load balencing. I don't know what percentage of an alternator load is friction based vs electrically based. The firctional losses will surely drop with decreased RPM, but they spin pretty freely when not energized....

Matt

 

check http://www.eurosporthighperformance.com they've had this item available for over a year now. with a stock size version i believe though

 

This newest pulley we added is a very good one and fits with our other pulleys. Yes we have a bunch of them now, but they all cater to a certain customer. Some one with JCW car would by one of the larger crank pulleys (that is who the parts were originally designed for), and when doing that they will increase the speed of all things driven by it. The AC, alternator and of course supercharger all all driven by it. The AC pulley is a special pulley and isn't something we will make. Also it is just an idler when the AC isn't on. So no power drain.

The alternator has weight to it, and is being over driven from the larger crank pulley, no naturally bringing the Alternator back to normal speeds willl free up some more HP.

We choose 5% because a slight amount of under driving is ok, without going to far and causing charging issues. We have found with others car that anything more than 10% starts to cut into the charging ability.

Is is necessary? Well, is a fun fast car necessary, not really but i sure want one! Is is necessary because of a danger with over spinning the Alternator? No. This is because the alternator is only spinning 2-4% faster than normal. If you look at the actual RPM the ALT is spinning we are only adding a few hundered RPM to it at redline with a 4% crank pulley.

Hope that answers most of the questions and concerns.

 

Guys... this isn't a new concept.

Underdrive pulleys have existed in two basic varients for years.

1) smaller crank pulley
2) smaller accessory pullies

The goal is the same, to reduce the amount of energy put into driving the accessories. There's no risk with this product, it's not something that has to be proven. I will probably buy one to use with my stock-size Alta crank pulley (which I've yet to buy). The only person I wouldn't sell one to is the guy with the big stereo system who spends most of his time sitting at stop lights.

 

Jeff, how hard is this to install? I haven't look down there but will it require special tools and motor lift?

Thanks,
Sid

PS...the diverter should be at your desk any moment

 

Installation is a bit tricky. Just because of the space availible. A long wrench and socket, belt and vise grips, and the good ole motor lift trick, will get the job done. The pulley is just slid onto the ALT so that part is somewhat easy.

 

back from the dead: while searching for oversized alternator pulley came up with this thread
i'm surprised no one noticed: overdrive crank pulley will make alternator spin faster and smaller alternator pulley will only add rotation speed
anyway ...back to searching