Shell Helix 10W/60 full synthetic

It was intended to be use only in severe duty, not normal operation.

 

This

 

10W-60 oil is for engines with finger followers and high RPMs.
F355s have direct actuated hydraulic bucket tappets (not finger followers.)

F355s driven even at aggressive back road performance levels need nothing more than xxW-40 oils, with an operating viscosity of 12-14 cSt.

F355s drivin on race tracks with oil temperatures below 275ºF, need an oil with an HTHS greater than 4.2 CP.

F355s driven on race tracks in real races where one would rather win than slow down when the oil gets over 275ºF need xxW-50 oil with an HTHS number over 5.0 CP.

Notice that the two later use scenarios do not use the grade-weight of the oil to determine suitability of the oil for the application. A different part of an oil specification is needed, and this one is the HTHS viscosity. HTHS is measured at 305ºF under high shear conditions (high RPMs). The original SHell Helix 10W-40 oil Ferrari specified had and HTHS viscosity of 4.2 cP, and Ferrari set the oil red line at 305ºF.

I, myself, like to keep one grade-weight away from the oil redline--which is a point where wear starts to increase greatly. It just so happens that one grade-weight higher in viscosity xxW-40 -> xxW-50 give 30ºF of margin. That is an xxW-40 oil at 275ºF will have the same viscosity as an xxW-50 oil at 305ºF. One can interpret this 2 ways: 1) if the oil gets too hot, use a heavier oil, 2) if the oil gets too hot, get a bigger oil cooler and stay with the same oil viscosity.

 

Ferrari specifically suggested Helix 10-60 for severe use.