Loud bang on boost

[Benjer182]

Ok next question about my new 5 is, when give it some on boost some times it gives out a huge bang and throws you forward, I have a new turbo sorted and that is stage 1 it already has a cone filter and a dual depth side mount and from what I can gather a "cup mod " where the pipes are routed different and no dump valve but I am going to fit one so whats up ? What do I need to change or do ?
Thanks guys

[Matt@CodeRedMotorsports]

Knock sensor and over boost still connected?
Knock sensor is a funny looking silver thing normally screwed into the head near the spark plugs, over boost is on the turbo to inter cooler pipe (the short one).
Disconnect one at a time, it MIGHT be the problem.....

[Brigsy]

Knock sensor wont cut the ignition so leave that be. If the overboost is still connected it will most likely be that.

If theres no overboost switch connected up check your plug gaps & make sure they are the correct type fitted, check the king lead isnt damaged, check tdc wire isnt sat on the top of the turbo and melting.

If all else seems ok the votage could be low i.e. alternator failing and the spark is weak, seen this happen before.