Rennmeister

Twenty-five years after the original Type RA rolled off the production lines in Japan the US market is finally getting it’s own. Apart from the monster 6-piston monobloc brakes and carbon fiber roof, the USDM Type RA comes with “upgraded pistons” and “more aggressive” ECU mapping. This lead to many Subaru enthusiasts speculating on just how upgraded the pistons really are. So Jeff Sponaugle took it upon himself to order a fresh, new Type RA shortblock from Subaru to find out. This is what he found.

What is Detonation? Detonation is when the air : fuel mixture burns at an extremely fast rate due to combustion chamber conditions resulting in a sharp rise in cylinder pressure and temperature. Detonation can vary in intensity from light, moderate, to severe depending on several factors.