4 hole pistons

[lovechild]

Just looking at Jorns set up from saturday and noticed hes using 4 hole 1.3 mm pistons, with 650wt durango oil at the front. What oil roughly will that translate to with 6 hole 1.2 mm pistons? is it simply a direct comparison? ie 1.3 x pi x 4 vs 1.2 x 6 x pi? if so for an equivalent 1.2mm 6 hole piston, I would need an oil far in excess of 650 wt correct? or not?

Thanks

[Legacy555]

4 x 1.3mm and 650cSt oil
is roughly the same as
6 x 1.2mm and 800 cSt oil
becuase this is worked out using hole area to piston area ratio, times the oil viscosity it doesn't take into account the losses around each hole. But is good for a rough guide.

Might be a good idea to drill and tap two holes in a set of 6x1.3mm pistons and glue some grub screws in.