Hi guys looking for some help , I’ve recently upgraded my dyno to an eddy brake since doin this I’m having issues with a big dip in my graph while using the brake in power sweep mode , occurs every run between 70-90mph 

if I run inertia only I don’t have this issue , I’ve also worked out if I run 3rd gear instead of 4th I don’t get this problem either 

I’ve made sure all wires etc are as far as possible away from the brake unit and also tried a new load cell and it’s still the same 

any help much appreciated