This may be a dumb question but why isn’t there a guide for Sirloin Steak?
I don’t think I’ve seen a guide for every cut of meat on any animal. Sirloin falls into the tender cuts, and can be treated as any other steak or tender cut.
Stephan, there are guides.
You might find it useful to narrow your search to something less generic. Examples are; Top Sirloin, Wing Steak, NY Strip Steak, Delmonico Steak, Bottom Sirloin Steak, - all being sirloin steaks.
Or perhaps better, learn to create your personal SV cooking guide by selecting your preferred degree of doneness and its respective cooking temperature. Those generally accepted temperatures for steak are as follows:
Rare 125ᴼF or 50ᴼC
Medium Rare 130ᴼF or 55ᴼC
Medium 140ᴼF or 60ᴼC
Next decide the duration of the cook according to meat’s thickness and your desired tenderness. Let Dr. Baldwin inform you as to time.
If you don’t use Metric measurements consider 25 mm to be the equivalent of an inch. Tender and well aged steaks are done when temperature equilibrium has been reached, For added tenderness cook for as long as 4 hours.
Keep detailed records of every cook so you can replicate all your successes.