I'm obviously biased, but I'd say trust the tool. It's specifically designed and tested to produce factory-correct tension.Richey wrote: Sat May 09, 2026 4:56 am If I understand the video on a new belt I should hit 7ft/lbs at the N mark (installing a new belt). I used a digital torque wrench set to 7ft/lbs and adjusted the tension to where it hits 7ft/lbs at the N mark.
But.... Every video I watch says I should be able to barely move the water pump pulley. At 7ft/lbs I can't, at around 5ft/lbs I can.
What should I do in this case? Set it at 7ft/lbs then slowly a back off until I can rotate the water pump pulley or leave it like it is?
The whole point of the 3D printed tool is to inject an objective, repeatable measurement into the process instead of relying on subjective tests like twisting the belt or seeing whether the pump pulley slips. I'm a broken record on this, but the fact that people often get away with those methods only proves these cars can tolerate out-of-spec tension fairly well -- even if not optimal for the long-term health of all the affected parts. It doesn't mean those methods reliably produce the correct factory tension in my experience -- they can be hit or miss with too many uncontrollable variables in play.
With the tool, if the "N" mark lines up with the rail using the specified 7 ft-lbs, then based on actual testing and measurable force, the belt is within or very close to Porsche's spec for a new belt.
Also, thinking about it, do the "twist the pulley" methods even distinguish between new and used belt specs? Porsche does. The used-belt spec is substantially looser. As an experiment, set the belt to where you can just twist the pulley, then check it with the tool at 7 ft-lbs. I wouldn't be surprised if it lands much closer to the "U" (used belt) range than the "N" range for a properly tensioned new belt.
