I've just had a new back box fitted on my UK300 impreza and it has decreased the performance of the car a hell of a lot.

When u accelerate it takes ages for the turbo to kick in and also the car shakes like the fuel and air ratio is wrong.

Any ideas???

 

Bloody hell what back box is it? 1/2 inch? You sure that its that and not something else?

 

its a twin 4 and half inch. i dont know what else it could be as the car was running fine up until i had the back box fitted. and i had it fitted professionally through a powerflow outlet.

 

Stick a pic up if you can to show us what you got.What size is the actuall back box?Maybe its just not freeflowing enough.Have you got any engine check lights on?

 

yes i have had the CEL on a few times. the back box is a slightly smaller box than standard.