Noise under full boost

[muzzyd]

There seems to be a lot of noise and lack of boost/power when flooring it in every gear.  The noise sounds like machine gun fire and the car stutters.  The noise sounds as if it is coming from the rear of the exhuast.  You can build up the power and it goes fine, just doesnt seem to take the foot to the floor.  

It didnt do it so much previously and seemed ok.

Actuator gone/going?  If so how much to replace and where from?

Any ideas?

[Gman]

Sounds like overboost or boost spikes- do u have a boost guage?  Mine does this because of my exhaust (to free flowing).  I\'m going for a remap to sort this out

[muzzyd]

I have a boost gauge bu tit is not fitted yet, waiting to get it done.  I suspected that or the actuator.  Think my exhaust is also a straight through.

[Gman]

Well i had a Fuel Cut Defender on my ecu and it was boosting somtmes to 1.4 bar!  Put the bung in the exhaust and took the fuel cut thing off and now it is better but stutters when it boosts higher than 0.9 bar.  So i guess i just need a map so the turbos and other stuff can handle my exhaust.  (the car is still running the same map as it was in Japan as my hand controller is buggered)

Do you have an aftermarket ECU or standard? and is your car an older 3rd gen? as there only had 8 bit ecu\'s i think and thus werent great with mods such as exhausts.