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Try a NAPA 25-060650 belt. I use it to make sure I cant throw one off from the slack the motor will put in a stock length belt. You have to put your idler all the way down and slide the belt over the power steering pump pulley to get it on. That is with an under driven/size alt. pulley like you have.

I have never lost that belt on its own without the blower belt getting into it. You are not going to throw the belt on that setup.
 

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Discussion Starter · #3 · (Edited)
Ok well see my problem is Im wondering if the dayco belt i found, that fits real tight basically only goes on with idler full down and it stays there once on, is making a strange noise happen...this noise is almost like a grinding noise while the car is idling and will go away with turning A/C on but with A/C off its pretty darn loud... and noise seems to be coming from A/C compressor area

Im wondering if this belt is TOO tight and the change in angle from having the alternator pulley smaller is putting excess tension on the A/C compressor or maybe its just the clutch of the compressor chattering into the compressor when not engaged or some debris is in between the clutch of the compressor and the compressor itself and causing the noise when the A/C is off aka clutch disengaged?
 

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You do want a little movement in the tension or something like you are saying could happen. I have ran my setup for some time now and no issues with the AC compressor or anything else making noise.
 

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Discussion Starter · #5 ·
Ok so I did some research it seems our stock belt (just using dayco part# for reference) is: dayco 5060643 64.25" effective length

the belt I had just gotten to fit real tight previously after changing alternators is:
dayco 5060630 63" effective length (1.25" less effective length than stock belt)

Now I measured the difference in pulley diameter and found my current alternator to have a 0.21" smaller pulley diameter so I would think taking half of that is the effective decrease in belt length of about 0.105" and so the closest dayco belt I could find for that change would be:
dayco 5060640 64" effective length (0.25" less effective length then stock belt)
or dayco 5060635 63.5" effective length (0.50" less effective length then stock belt)

anyone wanna chime in on which belt I oughta go with? because while the dayco 5060630 with 63" effective length I have on there fits there isnt much play in the tensioner but there is some (as in with belt on and socket on the tensioner I can rotate the tensioner from 1 o'clock to about 2 o'clock and thats as much as it goes)...I just don't want to prematurely wear out belts or kill my gas mileage with TOO tight of a belt if that makes sense?
 
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