Nerd’s Eye View: Inside Fredric Aasbo/Papadakis Racing’s Amazing V8 eating 2AR Toyota Engine


The 2AR uses pretty conventional piston rings.The top compression ring is chrome faced and is low tension at 1.1mm wide, important for the high piston speeds this long stroke engine sees.  The second ring is ductile iron with a Napier contour which is good for controlling oil consumption.  The second ring is nitrided for long life.  The oil ring has two rails and a separator with a third support ring because the piston pin bore intrudes on the oil ring space.
The 2AR runs on E85 race fuel.  Look how clean the dome is after a season of Formula D abuse!
The mark of a well designed piston is the lack of scuffing on the skirt even after a lot of high boost and high RPM use.  This is pretty amazing considering how long this engine's stroke is, how high the piston speed is and how much boost pressure it runs.  All of this puts plenty of side load on the piston.
No trick taper wall lightweight tool steel piston pins here.  The 2AR uses conventional thick wall piston rings to stop bowing at high boost levels.  A taper wall pin would bend and spin the small end rod bushing out.  The pins are DLC coated for low friction.
With the E85 fuel burning cool, stock heat range 6 plugs can be used.  Look how clean they are after a half season of use!
The stock Toyota MLS steel head gasket is used and can take the pressure with proper block prep.


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