Throttle Body Sizing

In Formula Student application our engine is mandated to breath through a 20mm restrictor, this also modifies the inlet track from an Individual Throttle body to a Single Throttle Body. My team are making use of a natural aspirated motor bike engine Honda CBR 600 RR (producing a stock horsepower of 118.1bhp) with an engine capacity of 599cm^3 (0.599 litres) . We don't have a Dyno to carry out these tests for the optimal throttle body size. Putting all this into perspective please what size of throttle body would you recommend for our application that would give us the minimum airflow restriction and good torque modulation?

Most of the FSAE engines that I have seem have used a throttle in the 32mm to 44mm range, such as these Bosch Motorsport units.

Thank You. Also I would like to inquire if there were additional calculations or design considerations that were implemented to arrive at that throttle body size for FSAE engines.

That's a heck of a range - one nearly half/double the other.

The smaller would be better for control, with the latter being better for outright power, but it may be marginal?

Ese, I can't make any specific recommendation, but I would suggest using a plenum between the restrictor and the TB, if allowed, as it will give a more even, and higher, mass flow into the engine. I'd also look at feeding it cold air and try and minimise any heat sources that could heat the air and any induction components, as you want to keep the air mass cold for best efficiency. Keep the induction path smooth with flowing turns and avoid sudden changes in cross-section area.

Thank You, I really appreciate.