Do be honests i used to like the dump valves before bcos of the sound but after blanking mine of last week it wont be going back on. Runs so much better and smoother. I use my car daily on the dual carriage ways and with the dump valve the cr used to jerk alot whle i was in 5th gear coming on and off the throttle but now with it blanked off it drives perfect with no jerks, idling problems or any rough spots and i can hear a little chatter too