Hi
Say a car is running around 500bhp then 5 months later it is dyno'd and is only running 380, what could the possible causes be for its drop in power.
Engine is running as good as it always has,the only thing changed was coilpacks and plugs

cheers for the advice.

 

turbo fallen off lol .. thats quite a big drop after 5mths i would of thought only a small drop would be seen of maybe 5-10bhp... did you have it when it was 500bhp or have you just bought it?????????????????????

 

the mapper will be able to tell you where your losing power from that would be the person i would ask for advice first or any subaru specialist on scoobynet should be able to diagnose your problem if they had your car but to ask that question one can only speculate at an answer without looking over your car first.

 

another thing i should add if the car runs and feels the same i hate to say this but, maybe your car had 380 bhp to begin with? you would definately know the difference between that kind of power believe me.

 

I would guess, you bought a 500BHP (Engine BHP) got it dyno'd to find out it was "only" 380BHP at the wheels?! You can chop 20% (obviously give or take) off the Engine BHP to get the rough wheel BHP?! (I think)