How do you determine accessory belt tension?

Doing an accessory belt change is pretty straight forward. The hardest part is removing the rear under tray and the trim and access cover behind the seats. Use a the frequencies from the CS manual, the frequencies on the regular 360 manual are incorrect and have been updated by Ferrari to the CS specs.

I know this for sure, because the first belt change I did, I set the belt tensions to the specs in the paper 360 shop manual and the P/S belt squealed like a pig. It was no fun taking the car apart for free to reset the belt tensions.

The reason that the P/S belt frequency is so high, is because it has such a short run. Think of the belt like a guitar string. Compare two belts: One belt with a very long run at the same tension as a belt with a very short run. Like moving up the frets on the same string at the same tension on your guitar. The long belt will have a much lower frequency than the short belt even though the tension is the same in both belts.

 

Yes. Checking the frequency is pointless, as the hydraulic tensioner sets tension, no matter what you measure.
I set my tension until the pins slide in and out easily. I then turn the engine over 1-3 times and recheck.
Be sure you allow ample time in between adjustments, as the tensioner takes time to adjust. Like a full minute, or so.