It depends where you put the probe . It should be in the exhaust manifold for best results .Some companies put them after the turbo . If it's in the manifold it should max at 1250 degrees . After turbo is kind of not so acurate . Closer to the turbo the hotter in may be .The farther down the pipe the cooler it is . And it cools off quick farther away . If it is after turbo , I would say 1050-1150 max depending on how close to turbo it is .