[simpsonsman (OP)]

I just want to know about when you add sulphur to thermite, does it make it hotter, and if it does, how much hotter?

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I just want to know about when you add sulfer to thermite, does it make it hotter if it does, how much hotter

I suppose it could be hotter, since the Fe produced reacts exothermically with sulfur to form FeS; but you should also consider the melting and boiling heat of sulfur. Furthermore, adding not just a small amount of it would result in a deflagration, because it absorbs heat transforming into gas, so I wouldn't advise it to do it.
If, instead, you use gypsum, then sulfur is released in the reduction and reacts with Fe at the same time, so it's different.
How much hotter could it be = which temperature, is very difficult to establish theorically. To measure the temperature, you cannot certainly use a thermometre, so you should youse a pyrometer for example (but I don't have).