boost bouncing??

[workingdan]

I went to the track wed. and made a couple passes and my boost is all over the place. Any idea why it would bounce around so much? I have a adjustable waste gate and a grainger valve. What should my wastegate arm leangth be? Should it be long or short?
Thanks

 

[notacarlo]

If it is too long, exhaust pressure can push the gate open and you loose boost.

I would say you want the rod just short enough to have to pull it with tension over the gate arm. Like 1/4", then set the grainger valve for desired boost.

 

[DailyDrifter]

Make sure you vac line going to the boost guage isnt kinked.