Just dynoed my car. Boost spiked and dipped low on 91 so we loosened the preload on the actuator. 91 was perfect no more spike and dip. Then on the e85 tune on spool up and hitting peak boost it did it again as you can see in the dyno chart. It spools hard then slows down alittle then shoots back up. Was having this issue at base spring pressure so we replaced the iwg with a turbo smart 18psi.
I don’t know why the e85 map spikes and dips but 91 doesn’t after adjusting preload. Ebcs was swapped did same thing. During spool up it feels not smooth trying to figure this weird taper out.
What should I be looking for?

 

Hard to say for sure. To me, this looks like either a gate issue you are still dealing with or some weirdness in the ebcs control.

What's your wastegate duty cycle table look like in those areas?