I use a long stim thermometer and get my oil to 340 to 350 on a 13 to 15 lb. bird you cook for 3 1/2 min. per lb. of bird.
you have to watch the temp. and keep it at least 325 to 350 for the full time.it will turn out great.
I do inject my birds.I use the cajan butter, or garlic butter.I inject the legs,breast in several places,into the big part of the wing.
they are real crisp on the outside and moist and tender n the inside.the only way to cook a turkey.I love the wings ; they are real crisp.[8D]