for those wanting a CAI, but dont want to spend over 100$....

[04sleeper]

Does that mean a new alternator??
Hope not. Have no more $$$$$$$$

A new alternator is a worth while investment on ANY fox body. The stock systems are barely adequate for just the factory stuff, let alone adding stereo systems and underdrive pulleys.

 

[RUNINAGT]

1 7/8 pulley? Ok do you know what size belt? Do ya have a Ford or Gates part #

 

[04sleeper]

1 7/8 pulley? Ok do you know what size belt? Do ya have a Ford or Gates part #

Yes the 1 7/8 pulley is OK. As far as the belt size...... Are you running all the factory acc?

It should only be a little shorter than the belt you have now if so.

A little tip when trying to find a belt size.

Look at the numbers in it. They tell the belt size in inches. Example 815K6= 81.5" belt with 6 ribs. Or 810K6= 81" with 6 ribs.

The best way is to measure with a peice of string inside one of the grooves on the pulleys. Then measure it in inches and go buy the right size one.

 

[RUNINAGT]

Yup she's got all the O.E. items. Just the pulley change. Now I just had these things installed last week. Last night was the 1st time I noticed the dimming light thing.

 

[04sleeper]

Well I would still switch out the alt pulley for now and look into upgrading to a 3G alt later.

 

[RUNINAGT]

04sleeper you mean put the stock pulley back on with a smaller belt?

 

[04sleeper]

04sleeper you mean put the stock pulley back on with a smaller belt?

Yes, at the very least.

OK = Put the stock alt pulley back on.
Good = Put an overdrive alt pulley on.
Better = Put a 3G altenator with factory pulley on.
Best = Put a 3G with an overdrive alt pulley on.

Hope this helps.

 

[Black1987Stang]

Damn seems like everyone was bashing him at first, i agree u dont need one for a stock mustang BUT I really doubt hes gonna keep it stock. I would keep the a/c it doesnt rob horespower unless its on obviously and for the wieght savings, i would keep it on personally

 

[RUNINAGT]

OK thanks 04sleeper I guess we will install the O.E. pulley back on.

 

[RUNINAGT]

Update. We installed the O.E. alternator pulley last night and the charging sytem got better. No more dimming of the lights as the Bass is pumping. So far.

 

[Synned]

Um, I bought pulleys from 50resto.com and my crank pulley is actually smaller. Now the waterpump pulley is pretty big and the alternator is bigger, but the crank was smaller.

 

[RUNINAGT]

Um, I bought pulleys from 50resto.com and my crank pulley is actually smaller. Now the waterpump pulley is pretty big and the alternator is bigger, but the crank was smaller.

That's how there supposed to be. Last night I installed the factory alternator pulley back on to cure the low charging sytem issue. Suprisenly we were able to keep the same belt.

 

[04sleeper]

Um, I bought pulleys from 50resto.com and my crank pulley is actually smaller. Now the waterpump pulley is pretty big and the alternator is bigger, but the crank was smaller.

The crank is what everything runs off of. It is what spins the rest of the acessories. So if it is smaller then less belt will travel across it when it turns one full revolution.

The acessories are dependant on how fast the crank is spinning them so they are opposite. The bigger pulley you put on them the slower that ascessory spins. The smaller the acessory pulley the faster that acessory spins.

You have to think of the circumference of the pulley, not the diameter. Just a little change in diameter makes a big difference in circumference.

Remember Math class.
If you measure the distance around a circle and divide it by the distance across the circle through the center, you will always come close to a particular value, depending upon the accuracy of your measurement. This value is approximately 3.14159265358979323846... We use the Greek letter (pronounced Pi) to represent this value. The number goes on forever. However, using computers, mathematicians have been able to calculate the value of to thousands of places. View attachment 493431

Pulley diameter VS circumference:

6 inch diameter pulley (stock) = 18.84955591 inches of belt travel.
4 inch diameter pulley (street underdrive) = 12.56637061 inches of belt travel.
3 inch diameter pulley (race underdrive) = 9.42477796 inches of belt travel.

So if you put a street pulley kit on your car the 4 inch crank pulley is slowing the alternator down already by approximately 33%. Then you add a bigger alternator pulley as well and it spins even slower. So you are really spinning the alternator down twice! Hence low charge.

That's how there supposed to be. Last night I installed the factory alternator pulley back on to cure the low charging sytem issue. Suprisenly we were able to keep the same belt.

Actually depending on how short your belt was the tensioner will take up an inch or so of belt.

I hope this helps.

 

[RUNINAGT]

Remember Math class.
If you measure the distance around a circle and divide it by the distance across the circle through the center, you will always come close to a particular value, depending upon the accuracy of your measurement. This value is approximately 3.14159265358979323846... We use the Greek letter (pronounced Pi) to represent this value. The number goes on forever. However, using computers, mathematicians have been able to calculate the value of to thousands of places. View attachment 493420

Pulley diameter VS circumference:

6 inch diameter pulley (stock) = 18.84955591 inches of belt travel.
4 inch diameter pulley (street underdrive) = 12.56637061 inches of belt travel.
3 inch diameter pulley (race underdrive) = 9.42477796 inches of belt travel.

So if you put a street pulley kit on your car the 4 inch crank pulley is slowing the alternator down already by approximately 33%. Then you add a bigger alternator pulley as well and it spins even slower. So you are really spinning the alternator down twice! Hence low charge.



Actually depending on how short your belt was the tensioner will take up an inch or so of belt.

I hope this helps.

YEA what he said Yea I know the tensioner takes up some. just thought we were going to have to use a smaller belt, bu O'well

 

[Synned]

The crank is what everything runs off of. It is what spins the rest of the acessories. So if it is smaller then less belt will travel across it when it turns one full revolution.

The acessories are dependant on how fast the crank is spinning them so they are opposite. The bigger pulley you put on them the slower that ascessory spins. The smaller the acessory pulley the faster that acessory spins.

You have to think of the circumference of the pulley, not the diameter. Just a little change in diameter makes a big difference in circumference.

Remember Math class.
If you measure the distance around a circle and divide it by the distance across the circle through the center, you will always come close to a particular value, depending upon the accuracy of your measurement. This value is approximately 3.14159265358979323846... We use the Greek letter (pronounced Pi) to represent this value. The number goes on forever. However, using computers, mathematicians have been able to calculate the value of to thousands of places. View attachment 493415

Pulley diameter VS circumference:

6 inch diameter pulley (stock) = 18.84955591 inches of belt travel.
4 inch diameter pulley (street underdrive) = 12.56637061 inches of belt travel.
3 inch diameter pulley (race underdrive) = 9.42477796 inches of belt travel.

So if you put a street pulley kit on your car the 4 inch crank pulley is slowing the alternator down already by approximately 33%. Then you add a bigger alternator pulley as well and it spins even slower. So you are really spinning the alternator down twice! Hence low charge.



Actually depending on how short your belt was the tensioner will take up an inch or so of belt.

I hope this helps.

Thanks for the info! I never really thought about it.

 

[04sleeper]

Glad I could help.

 

[40th 2004Stang]

I've read the tech articles too that say the stock air box with the silencer removed and a K&N works just as well if not better. We did this experiment on the 04 GT. Went to the track, ran the car with the stock air box, K&N, silencer removed. The car went 14.30, 14.32, and 14.31 in stock form. Then we put the $40 CAI from ebay on it, with the blue filter that came with it. The car went 14.009, and 14.002 back to back. Did it pick up? I'd say it did, and well worth the $40.

 

[Euphoric306]

for anyone who cares, which nobody probably does


....the one billionth digit of Pi is a 9

 

[RUNINAGT]

I've read the tech articles too that say the stock air box with the silencer removed and a K&N works just as well if not better. We did this experiment on the 04 GT. Went to the track, ran the car with the stock air box, K&N, silencer removed. The car went 14.30, 14.32, and 14.31 in stock form. Then we put the $40 CAI from ebay on it, with the blue filter that came with it. The car went 14.009, and 14.002 back to back. Did it pick up? I'd say it did, and well worth the $40.

HMM :Track: I guess that's enough to say whether you lose or not.

 

[Maryland Stang]

I've read the tech articles too that say the stock air box with the silencer removed and a K&N works just as well if not better. We did this experiment on the 04 GT. Went to the track, ran the car with the stock air box, K&N, silencer removed. The car went 14.30, 14.32, and 14.31 in stock form. Then we put the $40 CAI from ebay on it, with the blue filter that came with it. The car went 14.009, and 14.002 back to back. Did it pick up? I'd say it did, and well worth the $40.

An '04 is not the same as a Fox.