What are the common modifications made to an EA81 to boost its power ?
By : Nigel Field The stock EA-81 is a nice solid little engine with great potential for an aircraft if modified. In stock configuration it will make about 75 HP at 4800 rpm and probably never wear out. At 3600 it is down the lower rpm is probably only making about 60 HP or less. By contrast, the iron block Honda Prelude also 1.8 litre, will make 125 HP at 5400 rpm. So, what do we do to get power up on the Subaru. There is no one answer. A number of things need to be done which all contribute their share of power. The first thing to do is to improve the mass airflow through the engine, which is after all just an air pump. This requires first that the cam shaft be reprofiled to allow the engine the “capability” to breath and scavenge better. I sent mine to formula power to be done but I think Stratus also will do this for about $120.00. This alone won’t improve it much unless the rest of the induction system is modified. The intake manifold is replaced with a custom one with larger diame
