hinson

As we all know, to determine whether a reaction of substitution is Sn1 or Sn2 is by following the reaction rates of different reaction mixtures containing controlled amount of reactants to find out the type of rate law such that if the rate law is first order, the reaction is Sn1 and if that is second order, the reaction is Sn2. My question is, how could we follow the reaction rate that involve intramolecular substitution? I think we can't do this by simply changing the reactant concentration as both the substrate and the nucleophile now are in the same molecule. How can we know whether that substitution is Sn1 or Sn2? e.g. epioxidation of CH3(Br)CHCH(OH)CH3