The tensioners are hydraulically loaded by the engine's oil pressure, in addition to the spring--without the engine running they do allow a bit more slack...
- 2003 GT, UPR X, FRPP 24lb/h, Magnaflow, PP 70mm TB & plenum,
Delta Force tuned, Steeda UDPs, Ralco flywheel,
RAM HDX clutch, 3.73s, 262 rwHP/305 lb-ft.
New ride (7/1/2013) 1998 Mercedes SL500-5.0L 32V VVT 326/347 HP/tq
Engineering is, at its base, making what you want from what you have.
At its extreme it is making what you want from what you can get.