Question on power of an engine

I have a formula for power output of an engine

P=2.pie.N.T

I am slightly confused on the N value, it is rotational speed.

I have a set of data for speed in r.p.m should i convert this to r.p.s and then use this?

My main objective is to calculate brake specific fuel consumption, BSFC, in Kg/KWh

So need to have the Power value in SI units, but is r.p.s the SI unit?

Any help much appreciated !

In general, P = T * ω, where ω is the rotational speed in Radian/s.
ω = 2 * π * r.p.m/60
Since, your torque units in Nm then you should change the r.p.m to r.p.s in your own formula.

What does the T stand for? Is it time? Seconds or hours???