Information

Why ABS?  Why PLA?

ABS is used on the larger plug due to the plug being in the engine bay.  ABS has better heat and UV resistance than PLA.  The glass transition temperature of ABS is roughly 221F while PLA is only 140F.  The glass transition temperature is when the part begins to change from rigid plastic to softening rubber.  This application is not overly critical as the rubber hose insulates the plug as well as the plug being basically pulled in to place by the engine vacuum.  If this was a boost application or structural bracket where rigidity is vital, then the glass transition (Tg) becomes critically important.

The melting point of PLA is around 330F and for ABS it is north of 450F, although quite as sharp of a point like PLA largely due to the structure of ABS.