You guys seem to be figuring ratio according to diameter.

I was calculating circumference and then doing the ratio calculations.

Of course, I was plugging in 6-1/16" as the crank-pulley diameter.



I see you are also using 2.7"-diameter for the pulley.

I thought the original stock Dodge/ND pulley diameter was 2.3"

I have found a source that has either 2.37" or 2.76" pulleys; which should I get ??



Thanks.

 

well I wonder since the IC and the non-IC have different crank pulley diameters if one should use the 2.76" on the non-IC(smaller crank pulley) and the 2.37" on the IC(larger crank pulley)

Do you have a part number handy for that 2.37" pulley?

 

I ?think? you have the crank-pulley theory backwards (I could be wrong), would not the larger crank-pulley spin the alternator FASTER ??


I don't know it to be fact that the stock pulley is 2.37, as I have not removed a belt and actually measured.

I do know that the rim-diameter of the one on my non-I/C is right at 2-3/4", so no way is the belt-surface going to be 2.76.

Where I got the 2.37 is from several E-Bay-etc. sources having "2.37-O.D. alternator pulleys---O.E.M. replacement for Dodge/Cummins".

Given my rim-diameter of 2.75+or-, the 2.37-O.D. looks about right.

I don't have a part-number for either size just yet, as I am awaiting a response from the source.

Thanks.

 

Yes it appears that I do,

6.5/2.37=2.74

8/2.7=2.96

to keep the ratio's closer.

 

Not to nitpic; but, shouldn't it be :

6.5/2.37 = 2.74

8/2.7 = 2.96


But then, I could be wrong.


You swapping figures around has went and flipped my brain bottom side upwards.

 

ah shoot, I think I was sleeping this morning I fixed it up there also

 

Anyways, I'll wait for you guys to figure out the pulley stuff....

In the meantime, I've looked high and low all around here everywhere I can think of and cannot find the fuse. Does this look like it will fit the bill for a good fuse in this application, Jim?

http://www.defender.com/product.jsp?...3927&id=178109

 

This may be better :


http://www.delcity.net/store/High-Am...s/p_795291.a_1

I have had good dealings with these people before.


Look around their site, as they also have the holders for the fuses :

http://www.delcity.net/store/MEGA®-F...r/p_795652.a_1

: and lots of other affordable goodies.

 

Looks like same fuse for half the price....

 

yeah I think i'm still confused on the pulleys.

the Leece neville pulley that Jim and I got is 2.7" right?

So if thats the case then to get the same rpms on the non IC a IC truck would need a pulley in the 3.3" diameter range. I'll just try to make it even more confusing.

Also the fuse holder I got, came from NAPA, it holds the big AMG(??) fuses. Just look through their bussman catalog, they had to bring it in from their warehouse, but that was like half a day.

 

Ok guys here goes, Thank God for a calculator.
I think on an IC truck you would be ok using a 3.00" Diameter pulley if you could find one.

Non-Intercooled
6.50/2.70=2.41:1 x 800RPM=1925.925925 Idle RPM
6.50/2.70=2.41:1 x 3200 RPM=7703.703702 Maximum RPM

Intercooled
8.0/2.70=2.962962962:1 x 800=2370.370369 Idle RPM
8.0/2.70=2.962962962:1 x 3200=9481.481478 Maximum RPM

8.0/3.0=2.666666666:1 x 800=2133.333332 Idle RPM
8.0/3.0=2.666666666:1 x 3200=8533.333331 Maximum RPM

8.0/3.25=2.461538461:1 x 800= 1969.230768 Idle RPM
8.0/3.25=2.461538461:1 x 3200=7876.923075 Maximum RPM

The alternator is rated for 8000-RPM Continuous so depending on if your truck is an Automatic or a Manual and then factoring in your final gear ratio.

I calculated the maximum speed of 3200 RPM assuming you have upgraded the governor spring.

You would have to look at your driving habits and ask if you wind out the engine against the governor between gears.

I could not find any data as to what the maximum RPM of the alternator would be but I am sure it should be able to handle up to 10,000 RPM’s in burst as you shift.

I think I would choose the size to have it close to 2000 RPM’s for a good Idle Speed charge (if you really need this much power at an idle) and to have it somewhere in the middle to upper part of the power band while cruising.

Also remember that I called 800 RPM as a Fast Idle where the actual idle speeds will be somewhat lower reducing the low idle output only by about 20-amps.

I really do not want to make this too complicated, unless you drag race your truck just pick small pulley for a non-intercooled and a larger pulley if it is intercooled and call it good.

Please correct me if you think some of my figures are incorrect.

Jim

 

I think I need a bigger pulley...

Would you have a part number, or a catalog to look it up?

 

After the lawn-mower deck fell on my head a while ago, I can't think straight enough to cipher proper; warped a good mower deck, too.

Considering I don't drive like a race truck, and I am non-I/C, should I get the 2.76 or the 2.37 ??


Maybe I should get them all 2.76, as one of the trucks is I/C, yet I would like to keep all of the alternators as much the same as possible.


55-MPH = 1600-RPM in my personal truck.

What do you guys think ??

Thanks.

 

Go to E-Bay and type in "8-groove alternator pulley" and a whole bunch of them will come up.


This place costs more, but has a large selection :


http://store.alternatorparts.com/par...ovepulley.aspx

 

You can send me the difference.