Ordered new parts:
Injen cold air intake
Borla headers
Random Technology high flow cat
Borla headers
Random Technology high flow cat
Injen cold air intake
I also removed the hood vents (quite some time ago) to bring more cool air into the engine.
Completed pictures
after i installed the full aftermarket exhaust and intake i noticed a big increase in power at higher rpms but the lower ones seemed to lack the same amount of torque that the stock system had. this is due to the loss of backpressure from the free flowing exhuast and intake. after a lot of research it turns out that installing these aftermarket parts can do some damages to the engine mainly because of the new air/fuel ratio that is "all wrong" for the engine, now i say that because like i said at higher rpms the power was great but at lower rpms the loss of torque was really noticeable. normal compression ratio for practically all gasoline engines today is 14.7:1 and by removing all of the backpressure and allowing the engine to breathe one messes that up. so after looking around i came up with this solution:
its an apexi super air flow converter. this handy little device allows one to change the amount of air and fuel that is going into the cylinders so you can get back to that magic 14.7:1. along with some other neat things this will also let you run a more aggressive fuel curve and you can gain quite a bit more power while fixing the low rpm torque loss.
the other option that there is for this problem is to do a full blow ecu reflash but it costs a lot more and there was now where anywhere near where i live that could do it.
no install pics yet
turns out the s-afc doesnt work on the 01 imprezas and the only other realistic option i have now is to buy and install a proecm powerchip.
